Patent Application
20220371995
The present disclosure relates to the chemical synthesis technology, in particular to a synthesis method for halofuginone and halofuginone intermediates.
Halofuginone (Formula 1) is a halogenated derivative of natural product febrifugine, also known as bromochloro-halofuginone, chloroquinone, halofuginone. Halofuginone is a new type of broad-spectrum anticoccidial drug, which has strong inhibitory effect on many kinds of chicken coccidiosis. Halofuginone can obviously control the symptoms of coccidiosis and completely inhibit the discharge of oocysts (except for Eimeria cumulata) after use, thereby no longer polluting the environment and reducing the possibility of reinfection. Halofuginone can inhibit and kill the sporozoites in the three stages in the development cycle, namely: sporozoites, the first and second generation schizoites. Halofuginone has a unique chemical structure, so it has no cross-resistance with other existing anticoccidial drugs.
In addition, it is found that halofuginone specifically inhibits fibroblasts to produce type I collagen fibers, which prevents liver fibrosis, pulmonary fibrosis, scleroderma, and other diseases characterized by excessive synthesis of type I collagen. The inhibition of collagen synthesis leads to decreased in cell activity that play a key role in tumor growth, which in turn affects vascular growth and cell proliferation. It blocks the growth and metastasis of tumor cells. Therefore, the research of halofuginone in the treatment of malignant tumors entered the clinical trial stage approved by FDA in 2000. In 2002, halofuginone was approved in Europe for the treatment of systemic sclerosis.
The piperidine ring structure of febrifugine is unstable, so febrifugine and iso-febrifugine can be converted into each other through the process of “retro-conjugate-conjugate addition”, which becomes one of the main strategies for the total synthesis of febrifugine. For example, in 2001, Yasuo Takeuchi reported the isomerization of isofebrifugine and febrifugine (as shown in equation I). When isofebrifugine was heated in various solvents, it could be converted into febrifugine, and the reaction reached equilibrium, indicating febrifugine was successfully synthesized from isofebrifugine (Tetrahedron, 2001, 57, 1213-1218).
Halofuginone is a halogenated derivative of febrifugine, with only two hydrogens of the aromatic ring replaced by bromine and chlorine in chemical structure, while the piperidine ring is the same as febrifugine. It was found that halofuginone (1) and isofebrifugine (13) also have the property of mutual transformation. (Tetrahedron, 2017, 73, 5493-5499, as shown in equation II). Using this property, halofuginone was successfully synthesized from iso-halofuginone (CN201010257723.1, CN201310243084.7).
According to the structural characteristics and inverse synthesis analysis of halofuginone, it can be divided into piperidine ring side chain and quinazoline fragment. The quinazoline fragment can be connected with three types of piperidine ring intermediates (A, B, C) to synthesize halofuginone (as shown in equation III). These docking methods and detailed synthesis routes were reported by Paul Evans et al in the review article on the synthesis of halofuginone [Bioorganic & Medical Chemistry, 2018, 26 (9): 2199-2220].
As mentioned above, the use of the interconvertible nature of halofuginone and isofebrifugine is one of the main strategies for the total synthesis of halofuginone, because it is easier to construct when the side chains of hydroxyl and carbonyl groups on the piperidine ring of febrifugine are in CIS structure. And further, when the side chains of hydroxyl and carbonyl groups are in CIS structure, they can form a hemiketal structure to reduce the protective steps of hydroxyl groups. B-type intermediates are the key intermediates of this synthesis strategy.
The key step in the synthesis of type B intermediates is how to introduce the 2-position side chain (G or H) in piperidine ring. There are mainly two methods for introducing the 2-position side chain in piperidine ring in the literature. One is through the allyl alkylation of N-protected piperidinone (D) (Chemical and Pharmaceutical Bulletin, 1999, 47, 905-906; Synthesis, 1999, 10, 1814-1818; Journal of Medicinal Chemistry, 2003,46, 4351-4359; ACS Medicinal Chemistry Letters, 2014, 5, 572-575; Patents US 20080004287, CN201010257723.1, CN201310243084.7). The other method is to synthesize intermediate E from 3-hydroxypyridine (F) through multi-step reaction, then subjected to allyl migration rearrangement reaction (Journal of medical chemistry, 2003, 46, 4351-4359; Chemical and Pharmaceutical Bulletin, 1999, 47, 905-906; Synthesis, 1999, 10, 1814-1818), as shown in equation IV below.
The common disadvantage of the above-described two methods is poor selectivity. If the same side chain is introduced at other positions on the piperidine ring, it can lead to impurities with similar structure, which is difficult for separation and purify as physicochemical properties are similar due to the similar structure.
In addition, by using this total synthesis method reported by this strategy, methoxyformyl, ethoxyformyl, tert butoxyformyl (BOC), benzyloxyformyl (CBZ), trichloroethoxyformyl (TROC) or benzyl (BN) are selected as the protective groups for the piperidine ring nitrogen atoms. These protective groups can be removed under strong acid, strong base or reduction conditions to prepare the target product, which is disadvantageous to the unstable property of halofuginone. As a result, the yield is low, the product quality is not good, or the purification is complicated.
In the literature reported by Takeuchi, Y et al., compound I reacted with boron trifluoride ether to form furan compound J (Heterocycles, 2000, 53, 2247-2252). We also encountered similar problems in the development of the synthesis routes. Racemic compound K was deprotected by TMSI, and produced compound L with a similar structure, as shown in formula V. It is concluded that the removal of protective groups with lewis acid mainly produces furan ring compounds (such as by-products J and L).
In the literature reported by Maiden T. M. M. et al. (Org. Biomol. Chem., 2018, 16, 4159), the Cbz protecting group of compound M was removed with hydrobromic acid, only 16% of the target product compound N was obtained, and the main product of deprotection is compound O (formula VI).
The authors of the article speculated that the production mechanism of the by-product was shown in formula VII.
In the process of route development, we also tried to remove the protective group of racemic compound K with hydrochloric acid or hydrobromic acid, and obtained almost the same result as above. As shown in formula VIII, only product P was obtained within 0.5 h, and product O was obtained by prolonging the reaction time, while the target product N was not detected. It is concluded that the deprotection with protonic acid mainly produces piperidine ring opening by-products and imine by-products (such as by-products P and O).
Similarly, the desired result can not be achieved by removing the protective group in the strong alkali condition. For example, in the literature reported by Laurence E. Burgess (Tetrahedron Letters, 1996, 37, (19), 3255-3258), compound Q was used to remove the ethoxyl group on the piperidine ring with potassium hydroxide to obtain the target product compound R, but the yield was only 10%, as shown in formula IX.
In some patents and literatures, the protective group of nitrogen on piperidine ring is removed by reduction. For example, in patents CN201010257723.1 and CN201310243084.7, zinc powder and acetic acid were used to remove Trichloroethoxyformyl (Troc) protected racemic compound S. When this experiment was repeated, we found that although there were no side reactions mentioned above, the bromine atoms on the aromatic ring were also reduced, forming racemic compound T. Similarly, we also tried hydrogen deprotection of racemic compound M catalyzed by palladium, and the reductive deprotection of bromine atoms also occurred to form racemic compound T, as shown in formula X.
There are many problems in the synthesis route even when using compound A, C or other types of intermediates, such as low total yield, harsh reaction conditions, expensive raw materials, and the need for column chromatography to separate and purify.
Therefore, the products prepared by the existing synthesis methods are difficult to meet the quality standards of halofuginone, and cannot meet the huge market demand for halofuginone, let alone meet the declaration requirements of ICH.
In addition, the absolute configuration of halofuginone is 2R, 3S, and the optical rotation is “+”, which means it has right-handed optical activity. However, halofuginone, a derivative of febrifugine, is used in veterinary medicine as a racemate without optical activity. In recent years, many studies on halofuginone have shown that the pharmacological activity of D-2R, 3S-halofuginone with the same absolute configuration as natural product halofuginone is obviously better than that of L-2S, 3R-halofuginone. Therefore, the synthesis of halofuginone with high optical activity is of great significance.
The piperidine ring segments of halofuginone and febrifugine contain two chiral centers in trans form, at 2-and 3-position. The reported chiral synthesis methods mainly include the following: (1) constructing the 2- and 3-position chiral centers by Sharpless asymmetric dihydroxylation or Sharpless epoxidation. (2) introducing the 3-position chiral central hydroxyl group through the reduction of carbonyl group by yeast. (3) introducing 3-position chiral hydroxyl group by acetylase. (4) constructing 3-hydroxy chirality through asymmetric aldol condensation catalyzed by chiral small molecule compounds. (5) Chemical resolution by brucine. (6) synthesis methods using chiral compounds as starting materials, etc. There are many disadvantages of asymmetric synthesis of optically active halofuginone or febrifugine, such as complicated synthesis route, harsh reaction conditions, low yield, complex separation and purification, and the use of highly toxic and expensive reagents.
Based on the above, the present disclosure provides a new synthesis method for halofuginone intermediate. The name of the intermediate is cis-2-(2-chloropropene)-3-hydroxypiperidine (with the structure shown in Formula 9), and the provided synthesis method for the intermediate has many advantages, such as simple process, few product impurities, no need of column chromatography purification, and high yield.
The detailed technical solution is as following.
A synthesis method for the halofuginone intermediate with the structure shown in Formula 9, comprising the following steps:
(a) alkylation reacting diethyl acetaminomalonate with 2,3-dichloropropene under the action of a base and a catalyst to form the compound of Formula 2;
(b) decarboxylation reacting the compound of Formula 2 in the presence of an acid catalyst to produce the compound of Formula 3;
(c) esterification reacting the compound of Formula 3 in the presence of an acid catalyst to produce the compound of Formula 4;
(d) nitrogen alkylation reacting the compound of Formula 4 with 4-halogenated butyrate under the action of a base and a catalyst, and then nitrogen protection reacting with amino protection reagent to produce the compound of Formula 5;
(e) Dieckmann condensation reacting the compound of Formula 5 under the action of the base to produce the compound of Formula 6;
(f) decarboxylation reacting the compound of Formula 6 in the presence of inorganic salt to produce the compound of Formula 7;
(g) reduction reacting the compound of Formula 7 under the action of a reducing agent to produce the compound of Formula 8;
(h) nitrogen deprotection reacting the compound of Formula 8 to produce the compound of Formula 9;
the reaction formulas are as following:
wherein,
R1 is selected from: methyl, ethyl, propyl, isopropyl or tert-butyl; preferably, methyl and ethyl;
R2 is selected from: methyl, ethyl;
R3 is selected from: methoxyformyl, ethoxyformyl, tert-butoxyformyl, benzyloxyformyl, trichloroethoxyformyl or benzyl, preferably benzyloxyformyl.
The present disclosure also provides a preparation method for the halofuginone intermediate with optical activity, named as cis-2-(2-chloropropenyl)-3-hydroxypiperidine. The method has advantages such as simple process, less impurities, and no column chromatography purification. The method can be applied to preparation of halofuginone with optical activity and realize large scale production of halofuginone with high optical purity.
The detailed technical solution is as follows:
A preparation method of cis-2-(2-chloropropenyl)-3-hydroxypiperidine with optical activity, comprises the following steps:
(1) In the first organic solvent, salt formation reacting the racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine with dibenzoyl tartaric acid or its derivatives to produce precipitate, and the precipitate is recrystallized to obtain a chiral double salt;
(2) In the second organic solvent, the chiral complex salt is neutralized to alkalinity with an alkaline aqueous solution to obtain cis-2-(2-chloropropenyl)-3-hydroxypiperidine with optical activity;
The racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine has the structure as shown in Formula (±)-9; The optical active cis-2-(2-chloropropenyl)-3-hydroxypiperidine has the structure as shown in Formula (+)-9 or Formula (−)-9; The dibenzoyl tartaric acid or its derivative has the structure as shown in Formula 15 or Formula 16; The chiral double salt has the structure as shown in Formula 14 or Formula 17; The reaction equations are as following:
wherein, each R is independently selected from: hydrogen or C1-C4 alkoxy.
The present disclosure also provides a synthesis method of racemic halofuginone. This method has advantages such as simple process, less impurities, no column chromatography, and high yield.
The specific technical scheme is as follows:
A synthesis method for halofuginone with the structure of Formula 1, comprises the following steps:
(i) reacting the compound of Formula 9 with an amino protection reagent under the action of alkali to produce a compound of Formula 10;
(j) reacting the compound of Formula 10 with olefin halogenation reagent and water, to produce a compound of Formula 11;
(k) reacting the compound of Formula 11 with the compound of Formula 12 under the action of a base, and then removing the 9-fluorenylmethoxyformyl protecting group on piperidine ring nitrogen, to produce a compound of Formula 13;
(1) isomerization reacting the compound of Formula 13 to produce a compound of Formula 1.
wherein, X is chlorine, bromine or iodine, preferably bromine.
The present disclosure also provides a synthesis method of halofuginone salt.
The detailed technical solution is as follows:
A synthesis method of halofuginone salt comprises the following steps: synthesizing halofuginone by the synthesis method for halofuginone descried above, then reacting the halofuginone with acid to obtain the halofuginone salt.
In some embodiments, the acid is hydrobromic acid, hydrochloric acid or lactic acid.
Understandably, in the above method for synthesizing halofuginone and halofuginone salt, the reaction products obtained from any step through step (a) to (l) can be used as raw materials to directly carry out subsequent reactions to synthesize halofuginone and its salt. For example, a compound of Formula 9 can be used as a raw material to synthesize halofuginone and halofuginone salts through step (i) to (l) as described above, or a compound of Formula 3 can be used as a raw material to synthesize halofuginone and halofuginone salt through step (c) to (l) as described above.
The present disclosure also provides a synthesis method for halofuginone with optical activity. The detailed technical solution is as follows.
A synthesis method for halofuginone with optical activity, comprising the following steps:
(3) reacting the cis-2-(2-chloropropenyl)-3-hydroxypiperidin with optical activity with an amino protecting agent in the presence of a base to form optically active compounds of Formula (+)-10 or Formula (−)-10;
(4) reacting the optically active compound of Formula (+)-10 or Formula (−)-10 with olefin bromination reagent and water to form optically active compound of Formula (+)-11 or Formula (−)-11;
(5) reacting the optically active compound of Formula (+)-11 or Formula (−)-11 with the compound of Formula 12 under the action of alkali, and then the 9-fluorenylmethoxyformyl protecting group on the piperidine ring nitrogen is removed to form the optically active compound of Formula (+)-13 or Formula (−)-13;
(6) The optically active compound of Formula (+)-13 orFormula (−)-13 is isomerized to produce the optically active halofuginone;
the optically active halofuginone has the structure as shown in Formula (+)-1 or Formula (−)-1, and the reaction formulas are as following:
The present disclosure also provides a synthesis method of halofuginone salt with optical property.
The specific technical scheme is as following:
A synthesis method for halofuginone salt comprises the following steps: synthesizing halofuginone by the synthesis method for halofuginone with high optical property descried above, then reacting the halofuginone with acid to obtain the halofuginone salt with high optical property.
In some embodiments, said acid is hydrobromic acid, hydrochloric acid or lactic acid.
Understandably, in the above method for synthesizing optically active halofuginone, any reaction products obtained from step (a) to (g) and (1) to (6) can be used as raw materials to directly carry out subsequent reactions to synthesize optically active halofuginone. For example, the racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine can be used as the raw material to synthesize the optically active halofuginone through step (1) to (6) described above, or the compound of Formula 3 can be used as the raw material to synthesize the optically active halofuginone through step (c) to (g) and (1) to (6) described above.
The present disclosure discovers that the reasonable selection of the protective group of piperidine ring nitrogen atom is very important in the synthesis for halofuginone. If the protective group is not selected properly, many by-products will be produced in the deprotection process, which will lead to low yield of the product, poor product quality, or difficult for purification. In the present disclosure, 9-fluorenylmethoxyformyl (Fmoc) is selected as the protective group of piperidine ring nitrogen atom, and its removal is very simple, which can be removed only by reacting in the secondary or tertiary organic amine for a few seconds or minutes, thus greatly reduces the generation of by-products. In addition, the present disclosure uses a synthesis strategy that is completely different from the prior art to synthesize the halofuginone intermediate. The synthesis method for halofuginone and halofuginone intermedium of the present disclosure solves the technical defects in current halofuginone production with many advantages, such as simple process, low cost, fewer by-products in the synthesis process, simple purification process, no need column chromatography purification, high yield, fewer impurities, high purity, controllable product quality, and easy to meet the requirements of ICH declaration, which can be used for industrial production of halofuginone.
Furthermore, in the present disclosure, the racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine is chiral separated with chiral dibenzoyl tartaric acid to obtain optically active cis-2-(2-chloropropenyl)-3-hydroxypiperidine, which is used to prepare the optically active halofuginone. The basic nitrogen atom of cis-2-(2-chloropropenyl)-3-hydroxypiperidine can salt formation react with chiral dibenzoyl tartaric acid. After salt formation, cis-2-(2-chloropropenyl)-3-hydroxypiperidine with optical activity can be obtained by simple crystal resolution. The chiral dibenzoyl tartaric acid used in the synthesis method of the present disclosure has many advantages, such as having wide sources, low price, simple preparation process, fewer product impurities, no need for column chromatography purification, and can be used for large-scale production and preparation for halofuginone with high optical purity. The synthesis method of chiral synthesis and its intermediates of the present disclosure solves the technical defects in the current synthesis for halofuginone, with many advantages such as simple synthesis process, low cost, fewer by-products in the synthesis process, simple purification process, no need for column chromatography purification, high product yield, fewer impurity, high purity, and controllable product quality. It overcomes the disadvantages of the existing synthetic routes of optically active halofuginone or febrifugine, such as harsh reaction conditions, low yield, complex separation and purification, or the use of highly toxic and expensive reagents.
The synthesis method for halofuginone and halofuginone intermediate according to the present disclosure is further described below through specific embodiments.
In the present disclosure, the compounds shown in Formula 8, Formula 9, Formula 10, Formula 11, Formula 13 and Formula 1 are referred as racemic compound when they are not marked with (+) or (−), or marked with (±). The stereoscopic structure in the Formula is relative configuration, not absolute configuration; the compounds in Formula 8, Formula 9, Formula 10, Formula 11, Formula 13 and Formula 1 are referred as chiral compounds with optical activity when marked with (+) or (−), and the stereostructure in the Formula is absolute configuration.
In one aspect, the present disclosure provides a synthesis method for the halofuginone intermediate having the structure as shown in Formula 9, comprises the following steps:
(a) alkylation reacting diethyl acetaminomalonate with 2,3-dichloropropene under the action of a base and a catalyst to form the compound of Formula 2;
(b) decarboxylation reacting the compound of Formula 2 in the presence of an acid catalyst to produce the compound of Formula 3;
(c) esterification reacting the compound of Formula 3 in the presence of an acid catalyst to produce the compound of Formula 4;
(d) nitrogen alkylation reacting the compound of Formula 4 with 4-halogenated butyrate under the action of a base and a catalyst, and then nitrogen protection reacting with amino protection reagent to produce the compound of Formula 5;
(e) Dieckmann condensation reacting the compound of Formula 5 under the action of the base to produce the compound of Formula 6;
(f) decarboxylation reacting the compound of Formula 6 in the presence of inorganic salt to produce the compound of Formula 7;
(g) reduction reacting reacting the compound of Formula 7 to produce the compound of Formula 8;
(h) nitrogen deprotection reacting the compound of Formula 8 to produce the compound of Formula 9;
the reaction Formulas are as following:
wherein,
R1 is selected from: methyl, ethyl, propyl, isopropyl or tert-butyl, preferably methyl and ethyl;
R2 is selected from: methyl, ethyl;
R3 is selected from: methoxyformyl, ethoxyformyl, tert-butoxyformyl, benzyloxyformyl, trichloroethoxyformyl or benzyl, preferably benzyloxyformyl.
In some embodiments, the base in step (a) is at least one selected from potassium carbonate, cesium carbonate, sodium carbonate, sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium hydride, lithium hydride and potassium hydride.
In some embodiments, the catalyst in step (a) is the combination of quaternary ammonium salt and iodide; wherein the quaternary ammonium salt was any one selected from tetrabutylammonium bromide, tetraethylammonium bromide, tetrabutylammonium iodide and benzyl triethyl ammonium chloride; and the iodide is any one selected from sodium iodide, potassium iodide, and lithium iodide.
In some embodiments, the molar ratio of the quaternary ammonium salt to the iodide is 1:(2-6).
In some embodiments, the solvent used in the alkylation in step (a) is any one selected from acetonitrile, methanol, ethanol, N,N-Dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane and 1,2-dichloroethane.
In some embodiments, the reaction temperature of the alkylation in step (a) is 20-120° C.
In some embodiments, the molar ratio of Diethyl acetaminomalonate, 2,3-dichloropropene, catalyst, and base in step (a) is 1:(1-2):(0.1-0.5):(1-3).
In some embodiments, the acid in step (b) is hydrogen chloride aqueous solution, and the concentration of the hydrogen chloride aqueous solution is 5-12 mol/L.
In some embodiments, the molar ratio of the compound of Formula 2 to hydrogen chloride is 1:(5-30).
In some embodiments, the acid in step (c) is any one selected from sulfuric acid, phosphoric acid, hydrochloric acid, and p-toluenesulfonic acid.
In some embodiments, the solvent for the esterification reaction in step (c) is at least one selected from ethanol, diethyl carbonate, dimethyl carbonate, methanol, propanol and benzyl alcohol.
In some embodiments, the reaction temperature of the esterification reaction in step (c) is 0-120° C.
In some embodiments, the base used in step (d) is any one selected from potassium carbonate, potassium bicarbonate, cesium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, lithium hydroxide, potassium hydroxide, triethylamine, diisopropylethylamine, 1,8-diazabicyclo[5.4.0]undecan-7-ene.
In some embodiments, the 4-halobutyrate in step (d) is any one selected from 4-bromobutyrate, 4-chlorobutyrate, and 4-iodobutyrate.
In some embodiments, the catalyst in step (d) is quaternary ammonium salt or a combination of quaternary ammonium salt and iodide, wherein the quaternary ammonium salt is any one selected from tetrabutyl ammonium bromide, tetraethyl ammonium bromide, tetrabutyl ammonium iodide and benzyltriethylammonium chloride, and the iodide is any one selected from sodium iodide and potassium iodide.
In some embodiments, the solvent in the alkylation of nitrogen in step (d) is any one selected from acetonitrile, methanol, ethanol, N,N-Dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane and 1,2-dichloroethane.
In some embodiments, the reaction temperature of the alkylation of nitrogen in step (d) is 20-120° C.
In some embodiments, in step (d), the molar ratio of compound of Formula 4, 4-halobutyrate, base, and catalyst is 1:(1-1.5):(1-3):(0.01-0.2).
In some embodiments, the amine protection reagent in step (d) is any one selected from benzyl chloroformate, di-tert-butyl dicarbonate, methyl chloroformate, ethyl chloroformate, trichloroethyl chloroformate, benzyl bromide, and benzyl chloride.
In some embodiments, in step (d), the molar ratio of the amine protection reagent to the compound of Formula 4 is (0.8-2):1.
In some embodiments, the reaction temperature of the nitrogen protection reaction in step (d) is 0-100° C.
In some embodiments, the 4-halobutyrate in step (d) is Ethyl 4-bromobutyrate.
In some embodiments, the amine protection reagent in step (d) is benzyl chloroformate, and the molar ratio of benzyl chloroformate to the compound of Formula 4 is (0.8-1.2):1, and the reaction temperature is 0˜50° C.
In some embodiments, the base in step (e) is any one selected from sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium hydride, lithium hydride, lithium diisopropylamide, sodium bis-(trimethylsilyl) amide, lithium bis-(trimethylsilyl) amide and potassium bis-(trimethylsilyl) amide.
In some embodiments, the solvent of Dieckmann condensation reaction in step (e) is any one or combination of two selected from tetrahydrofuran, toluene, xylene, methyl tert-butyl ether, methanol, and ethanol.
In some embodiments, in step (e), the molar ratio of base to the compound of Formula 5 is (1-3):1.
In some embodiments, the reaction temperature of the Dieckmann condensation in step (e) is −20 to 80° C.
In some embodiments, the inorganic salt in step (f) is any one selected from sodium chloride, lithium chloride, sodium bromide, and lithium bromide.
In some embodiments, the molar ratio of the inorganic salt to the compound of Formula 6 in step (f) is (1-3):1.
In some embodiments, the reaction solvent of decarboxylation in step (f) is a combination of organic solvent and water, wherein the organic solvent is any one selected from dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide.
In some embodiments, the volume mass ratio of the organic solvent, water and the compound of Formula 6 in step (f) is (3-5):(0.1-1):1.
In some embodiments, the reaction temperature of decarboxylation reaction in step (f) is 100 to 150° C.
In some embodiments, the inorganic salt in step (f) is lithium chloride, and the reaction solvent for decarboxylation is the combination of N,N-dimethylformamide and water.
In some embodiments, the reducing agent in step (g) is any one selected from sodium borohydride, potassium borohydride, lithium borohydride, lithium aluminum hydride, sodium bis(2-methoxyethoxy) aluminumhydride, borane, sodium amalgam and lithium tri-tert-butoxyaluminum hydride; preferably sodium borohydride.
In some embodiments, the solvent of the reduction reaction in step (g) is ethanol.
In some embodiments, the molar ratio of the reducing agent to the compound of Formula 7 in step (g) is (1-2):1.
In some embodiments, the reduction reaction temperature in step (g) is 0-10° C.
In some embodiments, R3 is benzyloxyformyl, and the compound of Formula 8 undergoes nitrogen deprotection reaction in the presence of acid to produce the compound of Formula 9, wherein the acid is at least one selected from hydrochloric acid, hydrobromic acid and sulfuric acid; and the solvent for the deprotection reaction in step (h) is acetic acid, water or the combination of water and alcohol, and the alcohol is any one from methanol, ethanol and isopropanol.
In some embodiments, R1 is ethyl; R2 is ethyl; R3 is benzyloxyformyl.
On the other hand, the present disclosure provides a synthesis method for optically active halofuginone, which is a synthesis method for cis-2-(2-chloropropenyl)-3-hydroxypiperidine with optical activity, comprising the following steps of:
(1) In the first organic solvent, salt formation reacting the racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine with dibenzoyl tartaric acid or its derivatives to produce a precipitate, which is recrystallized to obtain a chiral complex salt;
(2) In the second organic solvent, the chiral complex salt is neutralized to alkalinity with an alkaline aqueous solution to obtain cis-2-(2-chloropropenyl)-3-hydroxypiperidine with optical activity;
The racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine has the structure shown in Formula (±)-9; the optically active cis-2-(2-chloropropenyl)-3-hydroxypiperidine has the structure shown in Formula (+)-9 or Formula (−)-9; the dibenzoyl tartaric acid or its derivative has the structure shown in Formula 15 or Formula 16; the chiral complex salt has the structure shown in Formula 14 or Formula 17; the reaction equation is as follows:
wherein each R is independently selected from: hydrogen or C1-C4 alkoxy.
In some embodiments, the dibenzoyl tartaric acid of Formula 15 or its derivative in step (1) is L-(−)-dibenzoyl tartaric acid or L-(−)-di-p-methoxybenzoyl tartaric acid, and the dibenzoyl tartaric acid of Formula 16 or its derivative is D-(+)-dibenzoyl tartaric acid or D-(+)-di-p-methoxybenzoyl tartaric acid.
In some embodiments, the molar ratio of racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine to dibenzoyl tartaric acid or its derivatives in step (1) is 1:(1-2).
In some embodiments, the recrystallization is carried out in a mixed solvent of a third organic solvent and water with a volume ratio of (1-10):1; the third organic solvent is any one or more selected from ethanol, methanol, isopropanol, acetonitrile, 1,4-dioxane, and acetone.
In some embodiments, the recrystallization is carried out in a mixed solvent of a third organic solvent and water with a volume ratio of (3-5):1, wherein the third organic solvent is acetonitrile.
In some embodiments, the first organic solvent in step (1) is any one or more selected from ethanol, methanol, isopropanol, acetonitrile, dichloromethane, 1,4-dioxane, tetrahydrofuran, toluene, acetone, and ethyl acetate.
In some embodiments, the second organic solvent described in step (2) is any one or more selected from ethyl acetate, dichloromethane, and trichloromethane.
In some embodiments, the temperature of the salt formation reaction is 0-100° C.
In some embodiments, the temperature of the salt formation reaction is 20-40° C.
In some embodiments, the temperature of recrystallization is 0-30° C.
In some embodiments, the temperature of recrystallization is 15-28° C.
In some embodiments, the alkaline aqueous solution in step (2) is any one selected from sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, lithium hydroxide aqueous solution, potassium carbonate aqueous solution, and sodium carbonate aqueous solution, and the neutralization to alkalinity is to pH 8-14.
In some embodiments, the synthesis method for racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine with optical activity comprises the following steps:
(a) alkylation reacting Diethyl acetaminomalonate with 2,3-dichloropropene under the action of a base and a catalyst to form the compound of Formula 2;
(b) decarboxylation reacting the compound of Formula 2 in the presence of an acid catalyst to produce the compound of Formula 3;
(c) esterification reacting the compound of Formula 3 in the presence of an acid catalyst to produce the compound of Formula 4;
(d) nitrogen alkylation reacting the compound of Formula 4 with 4-halogenated butyrate under the action of a base and a catalyst, then nitrogen protection reacting with an amino protection reagent to produce the compound of Formula 5;
(e) Dieckmann condensation reacting the compound of Formula 5 under the action of a base to produce the compound of Formula 6;
(f) decarboxylation reacting the compound of Formula 6 in the presence of the inorganic salt to produce the compound of Formula 7;
(g) reduction reacting the compound of Formula 7 to produce the compound of Formula 8;
(h) nitrogen deprotection reacting the compound of Formula 8 to produce the compound of Formula 9; the reaction formulas are as follows:
R1 is selected from: methyL ethyl, propyl, isopropyl or tort-butyl: preferably, methyl and ethyl;
R2 is selected from: methyl, ethyl;
R3 is selected from: methoxyformyl, ethoxyformyl, tert-butoxyformyl, benzyloxyformyl, trichloroethoxyformyl or benzyl, preferably, benzyloxyformyl.
In some embodiments, the base in step (a) is at least one selected from potassium carbonate, cesium carbonate, sodium carbonate, sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium hydride, lithium hydride, and potassium hydride.
In some embodiments, the catalyst in step (a) is the combination of a quaternary ammonium salt and an iodide; wherein the quaternary ammonium salt is any one selected from tetrabutylammonium bromide, tetraethylammonium bromide, tetrabutylammonium iodide, and Benzyl triethyl ammonium chloride, and the iodide is any one selected from sodium iodide, potassium iodide, and lithium iodide.
In some embodiments, the molar ratio of the quaternary ammonium salt to iodide is 1:(2-6).
In some embodiments, the solvent used in the alkylation in step (a) is any one selected from acetonitrile, methanol, ethanol, N,N-Dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane and 1,2-dichloroethane.
In some embodiments, the reaction temperature of the alkylation in step (a) is 20-120° C. .
In some embodiments, the molar ratio of Diethyl acetaminomalonate, 2,3-dichloropropene, catalyst and base in step (a) is 1:(1-2):0.1-0.5):(1-3).
In some embodiments, the acid in step (b) is hydrogen chloride aqueous solution, and the concentration of the hydrogen chloride aqueous solution is 5 mol/L-12 mol/L.
In some embodiments, the molar ratio of the compound of Formula 2 to hydrogen chloride is 1:(5-30).
In some embodiments, the acid in step (c) is any one selected from sulfuric acid, phosphoric acid, hydrochloric acid, and p-toluenesulfonic acid.
In some embodiments, the solvent for the esterification reaction in step (c) is at least one selected from ethanol, diethyl carbonate, dimethyl carbonate, methanol, propanol, and benzyl alcohol.
In some embodiments, the reaction temperature of the esterification reaction in step (c) is 0-120° C.
In some embodiments, the base in step (d) is any one selected from potassium carbonate, potassium bicarbonate, cesium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, lithium hydroxide, potassium hydroxide, triethylamine, diisopropylethylamine, and 1,8-diazabicyclo[5.4.0]undecan-7-ene.
In some embodiments, the 4-halobutyrate in step (d) is any one selected from 4-bromobutyrate, 4-chlorobutyrate, and 4-iodobutyrate.
In some embodiments, the catalyst in step (d) is a quaternary ammonium salt or a combination of quaternary ammonium salt and iodide, wherein the quaternary ammonium salt is any one selected from tetrabutyl ammonium bromide, tetraethyl ammonium bromide, tetrabutyl ammonium iodide, and Benzyltriethylammonium chloride, and the iodide is any one selected from sodium iodide and potassium iodide.
In some embodiments, the solvent in the alkylation of nitrogen in step (d) is any one selected from acetonitrile, methanol, ethanol, N,N-Dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane, and 1,2-dichloroethane.
In some embodiments, the reaction temperature of the alkylation of nitrogen in step (d) is 20-120° C.
In some embodiments, the molar ratio of compound of Formula 4, 4-halobutyrate, base and catalyst in step (d) is 1:(1-1.5):(1-3):(0.01-0.2).
In some embodiments, the amine protection reagent in step (d) is any one selected from benzyl chloroformate, di-tert-butyl dicarbonate, methyl chloroformate, ethyl chloroformate, trichloroethyl chloroformate, benzyl bromide, and benzyl chloride.
In some embodiments, the molar ratio of the amine protection reagent in step (d) to the compound of Formula 4 is (0.8-2):1.
In some embodiments, the reaction temperature of the nitrogen protection reaction in step (d) is 0-100° C.
In some embodiments, the 4-halobutyrate used in step (d) is 4-bromobutyrate.
In some embodiments, the amine protection reagent in step (d) is benzyl chloroformate, and the molar ratio of benzyl chloroformate to the compound of Formula 4 is (0.8˜1.2):1, and the reaction temperature is 0˜50° C.
In some embodiments, the base in step (e) is selected from any one of sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium hydride, lithium hydride, lithium diisopropylamide, sodium bis-(trimethylsilyl) amide, lithium bis-(trimethylsilyl) amide, and potassium bis-(trimethylsilyl) amide.
In some embodiments, the solvent of Dieckmann condensation reaction in step (e) is any one or a combination of two selected from tetrahydrofuran, toluene, xylene, methyl tert-butyl ether, methanol, and ethanol.
In some embodiments, the molar ratio of the base to the compound of Formula 5 in step (e) is (1-3):1.
In some embodiments, the reaction temperature of the Dieckmann condensation in step (e) is −20 to 80° C.
In some embodiments, the inorganic salt in step (f) is any one selected from sodium chloride, lithium chloride, sodium bromide, and lithium bromide.
In some embodiments, the molar ratio of the inorganic salt to the compound of Formula 6 in step (f) is (1-3):1.
In some embodiments, the reaction solvent of decarboxylation in step (f) is a combination of organic solvent and water, wherein the organic solvent is any one selected from dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-Dimethylacetamide, N,N-dimethylformamide.
In some embodiments, the volume mass ratio of the organic solvent, water and the compound of Formula 6 in step (f) is (3-5):(0.1-1):1.
In some embodiments, the reaction temperature of decarboxylation reaction in step (f) is 100 to 150° C.
In some embodiments, the inorganic salt in step (f) is lithium chloride, and the reaction solvent for decarboxylation is the combination of N,N-dimethylformamide and water.
In some embodiments, the reducing agent in step (g) is any one selected from sodium borohydride, potassium borohydride, lithium borohydride, lithium aluminum hydride, sodium bis(2-methoxyethoxy) aluminumhydride, borane, sodium amalgam, and lithium tri-tert-butoxyaluminum hydride, preferably sodium borohydride.
In some embodiments, the solvent of the reduction reaction in step (g) is ethanol.
In some embodiments, the molar ratio of the reducing agent to the compound of Formula 7 in step (g) is (1-2):1.
In some embodiments, the reduction reaction temperature in step (g) is 0° C.-10° C. .
In some embodiments, R3 is benzyloxyformyl, and the compound of Formula 8 undergoes nitrogen deprotection reaction under the action of acid to produce the compound of Formula 9, wherein the acid is at least one selected from hydrochloric acid, hydrobromic acid, and sulfuric acid; the solvent for the deprotection reaction in step (h) is acetic acid, water or the combination of water and alcohol, and the alcohol is any one selected from methanol, ethanol, and isopropanol.
In some embodiments, R1 is ethyl; R2 is ethyl; R3 is benzyloxyformyl.
In the third aspect, the present disclosure also provides a synthesis method for racemic halofuginone with the structure shown in Formula 1, comprising the following steps:
(i) reacting the compound of Formula 9 with the amino protection reagent under the action of alkali to produce a compound of Formula 10;
(j) reacting the compound of Formula 10 with olefin halogenation reagent and water, to produce a compound of Formula 11;
(k) reacting the compound of Formula 11 with the compound of Formula 12 under the action of base, then removing the 9-fluorenylmethoxyformyl protecting group on piperidine ring nitrogen, to produce a compound of Formula 13;
(l) isomerization reacting the compound of Formula 13 to produce a compound of Formula 1.
wherein, X is chlorine, bromine or iodine, preferably bromine.
In some embodiments, the base in step (i) is any one selected from sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.
In some embodiments, the amino protection reagent described in step (i) is any one selected from 9-fluorenylmethyl chloroformate, 9-fluorenylmethyl-1-benzotriazolyl carbonate, and 9-fluorenylmethyl-n-succinimide carbonate.
In some embodiments, the solvent in step (i) is a combination of organic solvent and water, wherein the organic solvent is any one selected from 1,4-dioxane and tetrahydrofuran.
In some embodiments, the molar ratio of the base, the amino protection reagent and the compound of Formula 9 in step (i) is (1-5):(1-2):1.
In some embodiments, the reaction temperature in step (i) is 0-20° C.
In some embodiments, the olefin halogenation reagent in step (j) is any one selected from N-bromosuccinimide, N-chlorosuccinimide, n-iodobutanimide, trichloroisocyanuric acid, 1,3-dichloro-5,5-dimethylhydantoin, and 1,3-dibromo-5,5-dimethylhydantoin.
In some embodiments, the solvent in step (j) is any one selected from acetonitrile, tetrahydrofuran, and 1,4-dioxane.
In some embodiments, the molar ratio of the alkene halogenation reagent in step (j) to the compound of Formula 10 is (0.9-1.2):1.
In some embodiments, the reaction temperature in step (j) is −10 to 35° C.
In some embodiments, the olefin halogenation reagent in step (j) is N-bromosuccinimide; wherein the molar ratio of the olefin halogenation reagent to the compound of formula 10 is (0.9-1):1; and the reaction solvent is acetonitrile; and the reaction temperature is −10° C. to 10° C.
In some embodiments, the base in step (k) is any one selected from potassium carbonate, sodium carbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, cesium carbonate, sodium methoxide, sodium ethoxide, sodium tert-butoxide potassium tert-butoxide, sodium hydride, lithium hydride, lithium diisopropylamide, sodium bis-(trimethylsilyl) amide, lithium bis-(trimethylsilyl) amide, and potassium bis-(trimethylsilyl) amide.
In some embodiments, the solvent in step (k) is any one selected from acetonitrile, methanol, ethanol, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane, and 1,2-dichloroethane.
In some embodiments, the molar ratio of the compound of Formula 12 in step (k) and the compound of Formula 11, and the base is 1:(1-2):(0.8-1.2).
In some embodiments, the reaction temperature in step (k) is −10° C. to 25° C.
In some embodiments, the base used in step (k) is potassium hydroxide. The reaction solvent is N,N-dimethylacetamide. The molar ratio of the compound of Formula 12 and the base, the compound of Formula 11 is 1:(1˜1.1):(0.8˜1.2), and the reaction temperature in step (k) is ˜10 to 25° C.
In some embodiments, the reaction for removing the 9-fluorenylmethoxyformyl protecting group from piperidine ring in step (k), is carried out under the action of secondary organic amine or tertiary organic amine, preferably diethylamine.
In some embodiments, the reaction temperature for removing the 9-fluorenylmethoxyformyl protecting group from the piperidine ring in step (k) is ˜10° C. to 25° C. .
In some embodiments, the solvent for the isomerization reaction in steps (1) is any one or a combination selected from water, ethanol, methanol, n-butanol, n-propanol, tert- butanol, N,N-dimethylformamide, tetrahydrofuran and 1,4-dioxane.
In some embodiments, the reaction temperature of the isomerization reaction in step (1) is 50-80° C.
In some embodiments, the synthesis method of the said halofuginone comprises the following steps:
(a) alkylation reacting diethyl acetaminomalonate with 2,3-dichloropropene under the action of a base and a catalyst to form the compound of Formula 2;
(b) decarboxylation reacting the compound of Formula 2 in the presence of an acid catalyst to produce the compound of Formula 3;
(c) esterification reacting the compound of Formula 3 in the presence of an acid catalyst to produce the compound of Formula 4;
(d) nitrogen alkylation reacting the compound of Formula 4 with 4-halogenated butyrate under the action of a base and a catalyst, and then nitrogen protection reacting with amino protection reagent to produce the compound of Formula 5;
(e) Dieckmann condensation reacting the compound of Formula 5 under the action of the base to produce the compound of Formula 6;
(f) decarboxylation reacting the compound of Formula 6 in the presence of inorganic salt to produce the compound of Formula 7;
(g) reduction reacting the compound of Formula 7 under the action of a reducing agent to produce the compound of Formula 8;
(h) nitrogen deprotection reacting the compound of Formula 8 to produce the compound of Formula 9;
the reaction formulas are as follows:
wherein,
R1 is selected from: methyl, ethyl, propyl, isopropyl or tert-butyl; preferably, methyl and ethyl;
R2 is selected from: methyl, ethyl;
R3 is selected from: methoxyformyl, ethoxyformyl, tert-butoxyformyl, benzyloxyformyl, trichloroethoxyformyl or benzyl, preferably, benzyloxyformyl.
In some embodiments, the base in step (a) is at least one selected from potassium carbonate, cesium carbonate, sodium carbonate, sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium hydride, lithium hydride and potassium hydride.
In some embodiments, the catalyst in step (a) is the combination of quaternary ammonium salt and iodide; wherein the quaternary ammonium salt is any one selected from tetrabutylammonium bromide, tetraethylammonium bromide, tetrabutylammonium iodide and benzyl triethyl ammonium chloride; and the iodide is any one selected from sodium iodide, potassium iodide and lithium iodide.
In some embodiments, the molar ratio of the quaternary ammonium salt to the iodide is 1:(2-6).
In some embodiments, the solvent used in the alkylation in step (a) is selected from any one of acetonitrile, methanol, ethanol, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane and 1,2-dichloroethane.
In some embodiments, the reaction temperature of the alkylation in step (a) is 20-120° C. .
In some embodiments, the molar ratio of diethyl acetaminomalonate, 2,3-dichloropropene, catalyst and base in step (a) is 1:(1-2):(0.1-0.5):(1-3).
In some embodiments, the acid in step (b) is hydrogen chloride aqueous solution, and the concentration of the hydrogen chloride aqueous solution is 5 mol/L-12 mol/L.
In some embodiments, the molar ratio of the compound of Formula 2 to hydrogen chloride is 1:(5-30).
In some embodiments, the acid in step (c) is selected from any one of sulfuric acid, phosphoric acid, hydrochloric acid and p-toluenesulfonic acid.
In some embodiments, the solvent for the esterification reaction in step (c) is at least one selected from ethanol, diethyl carbonate, dimethyl carbonate, methanol, propanol and benzyl alcohol.
In some embodiments, the reaction temperature of the esterification reaction in step (c) is 0-120° C.
In some embodiments, the base used in step (d) is any one selected from potassium carbonate, potassium bicarbonate, cesium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, lithium hydroxide, potassium hydroxide, triethylamine, diisopropylethylamine, 1,8-diazabicyclo [5.4.0]undeca-7-ene.
In some embodiments, the 4-halobutyrate used in step (d) is any one selected from 4-bromobutyrate, 4-chlorobutyrate and 4-iodobutyrate.
In some embodiments, the catalyst used in step (d) is a quaternary ammonium salt or a combination of quaternary ammonium salt and iodide, wherein the quaternary ammonium salt is any one selected from tetrabutyl ammonium bromide, tetraethyl ammonium bromide, tetrabutyl ammonium iodide and benzyltriethylammonium chloride, and the iodide is selected any one from sodium iodide and potassium iodide.
In some embodiments, the solvent used in the alkylation of nitrogen in step (d) is selected any one from acetonitrile, methanol, ethanol, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane and 1,2-dichloroethane.
In some embodiments, the reaction temperature of the alkylation of nitrogen in step (d) is 20-120° C.
In some embodiments, the molar ratio of compound of Formula 4, 4-halobutyrate, base and catalyst in step (d) is 1:(1-1.5):(1-3):(0.01-0.2).
In some embodiments, the amine protection reagent in step (d) is any one selected from benzyl chloroformate, di-tert-butyl dicarbonate, methyl chloroformate, ethyl chloroformate, trichloroethyl chloroformate, benzyl bromide and benzyl chloride.
In some embodiments, the molar ratio of the amine protection reagent in step (d) to the compound of Formula 4 is (0.8-2):1.
In some embodiments, the reaction temperature of the nitrogen protection reaction in step (d) is 0-100° C.
In some embodiments, the 4-halobutyrate in step (d) is Ethyl 4-bromobutyrate.
In some embodiments, the amine protection reagent in step (d) is benzyl chloroformate, and the molar ratio of benzyl chloroformate to the compound of Formula 4 is (0.8˜1.2):1, and the reaction temperature is 0˜50° C.
In some embodiments, the base in step (e) is any one selected from sodium methoxide, sodium ethoxide, sodium tert-butoxide potassium tert-butoxide, sodium hydride, lithium hydride, lithium diisopropylamide, sodium bis-(trimethylsilyl) amide, lithium bis-(trimethylsilyl) amide and potassium bis-(trimethylsilyl) amide.
In some embodiments, the solvent of Dieckmann condensation reaction in step (e) is any one or combination of two selected from tetrahydrofuran, toluene, xylene, methyl tert-butyl ether, methanol and ethanol.
In some embodiments, the molar ratio of the base to the compound of Formula 5 in step (e) is (1-3):1.
In some embodiments, the reaction temperature of the Dieckmann condensation in step (e) is −20° C. to 80° C.
In some embodiments, the inorganic salt in step (f) is any one selected from sodium chloride, lithium chloride, sodium bromide and lithium bromide.
In some embodiments, the molar ratio of the inorganic salt to the compound of formula 6 in step (f) is (1-3):1.
In some embodiments, the reaction solvent of decarboxylation in step (f) is a combination of organic solvent and water, wherein the organic solvent is any one selected from dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide.
In some embodiments, the volume mass ratio of the organic solvent, water and the compound of Formula 6 in step (f) is (3-5) L:(0.1-1) L:1 kg.
In some embodiments, the reaction temperature of decarboxylation reaction in step (f) is 100° C. to 150° C.
In some embodiments, the inorganic salt in step (f) is lithium chloride, the reaction solvent for decarboxylation is a combination of N,N-dimethylformamide and water.
In some embodiments, the reducing agent in step (g) is any one selected from sodium borohydride, potassium borohydride, lithium borohydride, lithium aluminum hydride, sodium bis(2-methoxyethoxy) aluminumhydride, borane, sodium amalgam and lithium tri-tert-butoxy aluminum hydride.
In some embodiments, the solvent of the reduction reaction in step (g) is ethanol.
In some embodiments, the molar ratio of the reducing agent to the compound of formula 7 in step (g) is (1-2):1.
In some embodiments, the reduction reaction temperature in step (g) is 0° C.-10° C.
In some embodiments, R3 is benzyloxyformyl, and the compound of Formula 8 undergoes nitrogen deprotection reaction under the action of acid to produce the compound of Formula 9, wherein the acid is at least one selected from hydrochloric acid, hydrobromic acid and sulfuric acid; the solvent for the deprotection reaction in step (h) is acetic acid, water or the combination of water and alcohol, and the alcohol is any one selected from methanol, ethanol and isopropanol.
In some embodiments, R1 is ethyl; R2 is ethyl; R3 is benzyloxyformyl.
In the fourth aspect, the present disclosure also provides a synthesis method for halofuginone salt, included the following steps: synthesizing halofuginone by the synthesis method of halofuginone descried above, then reacting the halofuginone with acid to obtain the halofuginone salt.
In some embodiments, the acid is hydrobromic acid, hydrochloric acid or lactic acid.
Understandably, in the above method for synthesizing halofuginone and halofuginone salt, the reaction products obtained from any step through step (a) to (g) and (1) to (6) can be used as raw materials to directly carry out subsequent reactions to synthesize halofuginone salt. For example, a compound of Formula 9 can be used as a raw material to synthesize halofuginone and halofuginone salts through steps (i) to (l) as described above, or a compound of Formula 3 can be used as a raw material to synthesize halofuginone and halofuginone salt through steps (c) to (l) as described above.
In the fifth aspect, the present disclosure also provides a synthesis method for halofuginone with optical activity, comprising the following steps:
(3) reacting the optically active cis-2-(2-chloropropenyl)-3-hydroxypiperidin with an amino protecting agent in the presence of a base to form optically active compounds of Formula (+)-10 or Formula (−)-10;
(4) reacting the optically active compound of Formula (+)-10 or Formula (−)-10 with olefin bromination reagent and water to form optically active compound of Formula (+)-11 or Formula (−)-11;
(5) reacting the optically active compound of Formula (+)-11 or Formula (−)-11 with the compound of Formula F2 under the action of a base, and then the 9-fluorenylmethoxyformyl protecting group on the piperidine ring nitrogen is removed to form the optically active compound of Formula (+)-13 or Formula (−)-13;
(6) The optically active compound of Formula (+)-13 or Formula (−)-13 is isomerized to produce the optically active halofuginone.
the optically active halofuginone has the structure shown in Formula (+)-1 or Formula (−)-1, and the reaction equation is as follows:
In some embodiments, the alkali in step (3) is any one selected from sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.
In some embodiments, the amino protection reagent described in step (3) is any one selected from 9-fluorenylmethyl chloroformate, 9-fluorenylmethyl-1-benzotriazolyl carbonate, and 9-fluorenylmethyl-n-succinimide carbonate.
In some embodiments, the solvent in step (3) is a combination of organic solvent and water, and the organic solvent is either 1,4-dioxane or tetrahydrofuran.
In some embodiments, the molar ratio of the base, the amino protection reagent and cis-2-(2-chloropropenyl)-3-hydroxypiperidin in step (3) is (1-5):(1-2):1.
In some embodiments, the reaction temperature in step (3) is 0-20° C.
In some embodiments, the olefin halogenation reagent in step (4) is any one selected from N-bromosuccinimide and 1,3-dibromo-5,5-dimethylhydantoin.
In some embodiments, the solvent in step (4) is any one selected from acetonitrile, tetrahydrofuran and 1,4-dioxane.
In some embodiments, the molar ratio of the alkene halogenation reagent in step (4) to the compound of Formula (+)-10 or Formula (−)-10 is (0.9-1.2):1.
In some embodiments, the reaction temperature in step (4) is −10° C. to 35° C. .
In some embodiments, the reaction temperature is −10° C. to 10° C. .
In some embodiments, the base in step (5) is any one selected from potassium carbonate, sodium carbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, cesium carbonate, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium hydride, lithium hydride, diisopropyl amino lithium, sodium bis-(trimethylsilyl) amide, lithium bis-(trimethylsilyl) amide, and potassium. bis-(trimethylsilyl) amide
In some embodiments, the solvent in step (5) is any one selected from acetonitrile, methanol, ethanol, N,N-Dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane, and 1,2-dichloroethane.
In some embodiments, the molar ratio of the compound of Formula (+)-11 or Formula (−)-11 in step (5), the compound of Formula 12, and the base is (0.8-1.2):1:(1-2).
In some embodiments, the reaction temperature in step (5) is −10° C. to 25° C.
In some embodiments, the reaction for removing the 9-fluorenylmethoxyformyl protecting group from piperidine ring in step (5) is carried out under the action of secondary organic amine or tert-iary organic amine.
In some embodiments, the reaction temperature for removing the 9-fluorenylmethoxyformyl protecting group from the piperidine ring in step (5) is −10° C. to 25° C.
In some embodiments, the secondary organic amine or the tertiary organic amine is diethylamine.
In some embodiments, the solvent for the isomerization reaction in steps (6) is any one or a combination of two selected from water, ethanol, methanol, n-butanol, n-propanol, tert-butanol, N,N-dimethylformamide, tetrahydrofuran, and 1,4-dioxane.
In some embodiments, the reaction temperature of the isomerization reaction in step (6) is 50-80° C.
In some embodiments, the synthesis method for the optically active halofuginone also includes the step of preparing cis-2-(2-chloropropenyl)-3-hydroxypiperidine with optical activity, comprising the following steps:
(1) In the first organic solvent, salt formation reacting the racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine with dibenzoyl tartaric acid or its derivatives to produce a precipitate, which is recrystallized to obtain a chiral complex salt;
(2) In the second organic solvent, the chiral complex salt is neutralized to alkalinity with an alkaline aqueous solution to obtain cis-2-(2-chloropropenyl)-3-hydroxypiperidine with optical activity;
The racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine has the structure shown in Formula (±)-9; the optically active cis-2-(2-chloropropenyl)-3-hydroxypiperidine has the structure shown in Formula (+)-9 or Formula (−)-9; the dibenzoyl tartaric acid or its derivative has the structure shown in Formula 15 or Formula 16; the chiral complex salt has the structure shown in Formula 14 or Formula 17; the reaction equation is as follows:
wherein each R is independently selected from: hydrogen or C1-C4 alkoxy.
In some embodiments, the dibenzoyl tartaric acid of Formula 15 or its derivative in step (1) is L-(−)-dibenzoyl tartaric acid or L-(−)-di-p-methoxybenzoyl tartaric acid, and the dibenzoyl tartaric acid of Formula 16 or its derivative is D-(+)-dibenzoyl tartaric acid or D-(+)-di-p-methoxybenzoyl tartaric acid.
In some embodiments, the molar ratio of racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine to dibenzoyl tartaric acid or its derivatives in step (1) is 1:(1-2).
In some embodiments, the recrystallization is carried out in a mixed solvent of a third organic solvent and water with a volume ratio of (1-10):1; the third organic solvent is any one or more selected from ethanol, methanol, isopropanol, acetonitrile, 1,4-dioxane, and acetone.
In some embodiments, the recrystallization is carried out in a mixed solvent of a third organic solvent and water with a volume ratio of (3-5):1, wherein the third organic solvent is acetonitrile.
In some embodiments, the first organic solvent in step (1) is any one or more selected from ethanol, methanol, isopropanol, acetonitrile, dichloromethane, 1,4-dioxane, tetrahydrofuran, toluene, acetone, and ethyl acetate.
In some embodiments, the second organic solvent described in step (2) is any one or more selected from ethyl acetate, dichloromethane, and trichloromethane.
In some embodiments, the temperature of the salt formation reaction is 0-100° C.
In some embodiments, the temperature of the salt formation reaction is 20-40° C.
In some embodiments, the temperature of recrystallization is 0-30° C.
In some embodiments, the temperature of recrystallization is 15-28° C.
In some embodiments, the alkaline aqueous solution in step (2) is any one selected from sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, lithium hydroxide aqueous solution, potassium carbonate aqueous solution, and sodium carbonate aqueous solution, and the neutralization to alkalinity is pH 8-14.
In some embodiments, the synthesis method for racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine with optical activity comprises the following steps:
(a) alkylation reacting Diethyl acetaminomalonate with 2,3-dichloropropene under the action of base and catalyst to form the compound of Formula 2;
(b) decarboxylation reacting the compound of Formula 2 in the presence of an acid catalyst to produce the compound of Formula 3;
(c) esterification reacting the compound of Formula 3 in the presence of an acid catalyst to produce the compound of Formula 4;
(d) nitrogen alkylation reacting the compound of Formula 4 with 4-halogenated butyrate under the action of abase and a catalyst, then nitrogen protection reacting with an amino protection reagent to produce the compound of Formula 5;
(e) Dieckmann condensation reacting the compound of Formula 5 under the action of a base to produce the compound of Formula 6.
(f) decarboxylation reacting the compound of Formula 6 in the presence of the inorganic salt to produce the compound of Formula 7.
(g) reduction reacting the compound of Formula 7 to produce the compound of Formula 8;
(h) nitrogen deprotection reacting the compound of Formula 8 to produce the compound of Formula 9.
the reaction formulas are as follows:
wherein,
R1 is selected from: methyl, ethyl, propyl, isopropyl or tert-butyl; preferably, methyl and ethyl;
R2 is selected from: methyl, ethyl;
R3 is selected from: methoxyformyl, ethoxyformyl, tert--butoxyformyl, benzyloxyformyl, trichloroethoxyformyl or benzyl, preferably, benzyloxyformyl.
In some embodiments, the base in step (a) is at least one selected from potassium carbonate, cesium carbonate, sodium carbonate, sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium hydride, lithium hydride, and potassium hydride.
In some embodiments, the catalyst in step (a) is the combination of a quaternary ammonium salt and an iodide; wherein the quaternary ammonium salt is any one selected from tetrabutylammonium bromide, tetraethylammonium bromide, tetrabutylammonium iodide, and Benzyl triethyl ammonium chloride, and the iodide is any one selected from sodium iodide, potassium iodide, and lithium iodide.
In some embodiments, the molar ratio of the quaternary ammonium salt to iodide is 1:(2-6).
In some embodiments, the solvent used in the alkylation in step (a) is any one selected from acetonitrile, methanol, ethanol, N,N-Dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane, and 1,2-dichloroethane.
In some embodiments, he reaction temperature of the alkylation in step (a) is 20˜120° C.
In some embodiments, the molar ratio of Diethyl acetaminomalonate, 2,3-dichloropropene, catalyst, and base in step (a) is 1:(1-2):(0.1-0.5):(1-3).
In some embodiments, the acid in step (b) is hydrogen chloride aqueous solution, and the concentration of the hydrogen chloride aqueous solution is 5-12 mol/L.
In some embodiments, the molar ratio of the compound of Formula 2 to hydrogen chloride is 1:(5-30).
In some embodiments, the acid in step (c) is any one selected from sulfuric acid, phosphoric acid, hydrochloric acid, and p-toluenesulfonic acid.
In some embodiments, the solvent for the esterification reaction in step (c) is at least one selected from ethanol, diethyl carbonate, dimethyl carbonate, methanol, propanol, and benzyl alcohol.
In some embodiments, the reaction temperature of the esterification reaction in step (c) is 0-120° C.
In some embodiments, the base in step(d) is any one selected from potassium carbonate, potassium bicarbonate, cesium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, lithium hydroxide, potassium hydroxide, triethylamine, diisopropylethylamine, 1,8-diazabicyclo[5.4.0]undecan-7-ene.
In some embodiments, the 4-halobutyrate in step (d) is any one selected from 4-bromobutyrate, 4-chlorobutyrate, and 4-iodobutyrate.
In some embodiments, the catalyst in step (d) is quaternary ammonium salt or a combination of quaternary ammonium salt and iodide, wherein the quaternary ammonium salt is any one selected from tetrabutyl ammonium bromide, tetraethyl ammonium bromide, tetrabutyl ammonium iodide, and Benzyltriethylammonium chloride, and the iodide is any one selected from sodium iodide and potassium iodide.
In some embodiments, the solvent in the alkylation of nitrogen in step (d) is any one selected from acetonitrile, methanol, ethanol, N,N-Dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane, and 1,2-dichloroethane.
In some embodiments, the reaction temperature of the alkylation of nitrogen in step (d) is 20-100° C.
In some embodiments, the molar ratio of compound of Formula 4, 4-halobutyrate, base, and catalyst in step (d) is 1:(1-1.5):(1-3):(0.01-0.2).
In some embodiments, the amine protection reagent in step (d) is any one selected from benzyl chloroformate, di-tert-butyl dicarbonate, methyl chloroformate, ethyl chloroformate, trichloroethyl chloroformate, benzyl bromide, and benzyl chloride.
In some embodiments, the molar ratio of the amine protection reagent to the compound of Formula 4 in step (d) is (0.8-2):1.
In some embodiments, the reaction temperature of the nitrogen protection reaction in step (d) is 0-100° C.
In some embodiments, the 4-halobutyrate in step (d) is ethyl 4-bromobutyrate.
In some embodiments, the amine protection reagent in step (d) is benzyl chloroformate, and the molar ratio of benzyl chloroformate to the compound of Formula 4 is (0.8-1.2):1, and the reaction temperature is 0-50° C.
In some embodiments, the base in step (e) is any one selected from sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium hydride, lithium hydride, lithium diisopropylamide, sodium bis-(trimethylsilyl) amide, lithium bis-(trimethylsilyl) amide, and potassium bis-(trimethylsilyl) amide.
In some embodiments, the solvent of Dieckmann condensation reaction in step (e) is any one or a combination of two selected from tetrahydrofuran, toluene, xylene, methyl tert-butyl ether, methanol, and ethanol.
In some embodiments, the molar ratio of the base in step (e) to the compound of Formula 5 is (1-3):1.
In some embodiments, the reaction temperature of the Dieckmann condensation in step (e) is −20 to 80° C.
In some embodiments, the inorganic salt in step (f) is any one selected from sodium chloride, lithium chloride, sodium bromide, and lithium bromide.
In some embodiments, the molar ratio of the inorganic salt to the compound of Formula 6 in step (f) is (1-3):1.
In some embodiments, the reaction solvent of decarboxylation in step (f) is a combination of organic solvent and water, wherein the organic solvent is any one selected from dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-Dimethylacetamide, and N,N-dimethylformamide.
In some embodiments, wherein the volume mass ratio of the organic solvent, water and the compound of Formula 6 in step (f) is (3-5):(0.1-1):1.
In some embodiments, the reaction temperature of decarboxylation reaction in step (0 is 100 to 150° C.
In some embodiments, the inorganic salt in step (f) is lithium chloride, the reaction solvent for decarboxylation is a combination of N,N-dimethylformamide and water.
In some embodiments, the reducing agent in step (g) is any one selected from sodium borohydride, potassium borohydride, lithium borohydride, lithium aluminum hydride, sodium bis(2-methoxyethoxy)aluminumhydride, borane, sodium amalgam, and lithium tri-tert-butoxyaluminum hydride.
In some embodiments, the solvent of the reduction reaction in step (g) is ethanol.
In some embodiments, the molar ratio of the reducing agent to the compound of Formula 7 in step (g) is (1-2):1.
In some embodiments, the reduction reaction temperature in step (g) is 0-10° C.
In some embodiments, R3 is benzyloxyformyl, and the compound of Formula 8 undergoes nitrogen deprotection reaction under the action of acid to produce the compound of Formula 9, wherein the acid is at least one selected from hydrochloric acid, hydrobromic acid, and sulfuric acid; the solvent for the deprotection reaction in step (h) is acetic acid, water or the combination of water and alcohol, and the alcohol is any one selected from methanol, ethanol, and isopropanol.
In some embodiments, R1 is ethyl; R2 is ethyl; R3 is benzyloxyformyl.
In the sixth aspect, the present disclosure also provides a synthesis method for optically active halofuginone salt, comprising the following steps: synthesizing optically active halofuginone by the synthesis method for halofuginone descried above, then reacting the halofuginone with acid to obtain the optically active halofuginone salt.
In some embodiments, the acid is hydrobromic acid, hydrochloric acid or lactic acid.
Understandably, in the above method for synthesizing optically active halofuginone and its salt, the reaction products obtained from any step through step (a) to (g) and (1) to (6) can be used as raw materials to directly carry out subsequent reactions to synthesize optically active halofuginone. For example, the racemic cis-2-(2-chloropropenyl)-3-hydroxypiperidine can be used as the raw material to synthesize the optically active halofuginone through step (1) to (6) as described above, or the compound of Formula 3 can be used as the raw material to synthesize the optically active halofuginone through step (c) to (g) and (1) to (6) as described above.
Step (a): At room temperature, diethyl acetylaminomalonic acid (5.00 kg, 23.02 mol), anhydrous potassium carbonate (6.35 kg, 46.04 mol), potassium iodide (0.76 kg, 4.6 mol), tetrabutylammonium bromide (0.37 kg, 1.15 mol) and acetonitrile (25 L) were added into a 50 L reaction kettle. After being stirred for 20 minutes, 2,3-dichloropropene (3.07 kg, 27.62 mol) was added. The reaction was carried out at 85-90° C. and monitored by HPLC. After the end of the reaction, the reaction mixture was cooled to a temperature within 25° C., then added dropwise with diluted hydrochloric acid to neutralize the reaction mixture to pH 7-7.5. The reaction solution was left to separation, then the organic layer was concentrated under reduced pressure at 50° C. The concentrated residue was added with ethanol-water (1:10, 20 L) and stirred for 1 hour for crystallization. After vacuum filtration, the filter cake was washed with water to obtain compound of Formula 2, which was a yellow solid (wet weight 10.50 kg), which was not dried and directly put into the next reaction.
1H NMR (500 MHz, Chloroform-d) δ 5.28 (d, J=1.2 Hz, 1H), 5.17 (d, J=1.1 Hz, 1H), 4.26 (qd, J=7.1, 2.4 Hz, 4H), 3.47 (s, 2H), 2.03 (s, 3H), 1.55-1.51 (m, 1H), 1.27 (t, J=7.1 Hz, 6H).
13C NMR (126 MHz, Chloroform-d) δ 169.3, 167.3, 136.5, 117.8, 65.2, 63.0, 41.6, 23.0, 14.0.
HRMS (m/z): calc. for C12H19ClNO5 [M+H]+=292.0952; found, 292.0954
Step (b): At room temperature, the compound of Formula 2 (wet weight 10.5 kg, 23.02 mol) and hydrochloric acid solution (6 mol/L, 57.5 l, 345.27 mol) were added into a 100 L reaction kettle, stirred and heated to 100° C. for reflux reaction, and the reaction was monitored by TLC. After the end of the reaction, activated carbon (650 g) was added to the reaction kettle and cooled to not to exceed 50° C. After vacuum filtration, the filter cake was washed with water, then the filtrate was combined and concentrated under reduced pressure at 80-85° C. to remove the solvent to obtain compound of Formula 3, which was a light-yellow solid (4.05 kg). The product was directly put into the next reaction without further purification.
Step (c): At room temperature, compound of Formula 3 (4.05 kg, 21.77 mol), diethyl carbonate (12 L) and anhydrous ethanol (4 L) were added into a 50 L reaction kettle and stirred. Concentrated sulfuric acid (1.13 kg, 11.51 mol) was added dropwise and completed within 20-30 minutes. Then, heated to 85-95° C. for reflux reaction, and the reaction was monitored by HPLC. After the end of the reaction, the reaction solution was cooled to 50-60° C. and concentrated under reduced pressure, and the remaining liquid was diluted with water and cooled to not to exceed 10° C. 30% sodium hydroxide was added dropwise to adjust the solution to pH 8-9, then moved to room temperature for extraction using dichloromethane (10 L×3). After extraction, the organic layers were combined, added with anhydrous sodium sulfate and dried. After vacuum filtration, the filtrate was concentrated at 40° C. to obtain compound of Formula 4 which is a light brown oil (3.07 kg, The total yield of 3 steps is 75%).
1H NMR (500 MHz, Chloroform-d) δ 5.30 (d, J=1.3 Hz, 1H), 5.26 (q, J=1.1 Hz, 1H), 4.20 (q, J=7.1 Hz, 2H), 3.78 (dd, J=8.6, 4.8 Hz, 1H), 2.81 (ddd, J=14.2, 4.8, 1.1 Hz, 1H), 2.56 (dd, J=14.2, 8.6 Hz, 1H), 1.28 (t, J=7.1 Hz, 3H).
13C NMR (126 MHz, Chloroform-d) δ 174.5, 138.5, 115.9, 61.4, 52.3, 44.6, 14.3.
HRMS (m/z): calc. for C7H13ClNO2 [M+H]+=178.0635; found, 178.0628.
Note: in step (a), the product was wet without being dried, so the yield exceeded the theoretical value. Therefore, according to the 100% yield, the mole number of the compound of Formula 2 was 23.02 mol.
Preparation of Intermediate Compound of Formula 6 (R1=Et; R2=Et; R3=Cbz)
Step (d): At room temperature, compound of Formula 4 (3.07 kg, 17.26 mol), anhydrous sodium carbonate (5.49 kg, 51.79 mol), tetrabutylammonium iodide (0.64 kg, 1.73 mol) and toluene (9 L) were added into a 50 L reaction kettle, and toluene (6 L) solution of ethyl 4-bromobutyrate (3.37 kg, 17.26 mol) was added after stirring for 20 minutes. The reaction was stirred at 75-80° C. and monitored by HPLC. After the end of the reaction, the temperature was cooled to 20-25° C. Water (9 L) was added and stirred for 10-15 minutes, then benzyl chloroformate (2.94 kg, 17.26 mol) was added dropwise and completed within about 2-3 hours. The reaction was continuously stirred at 20-25° C. and monitored by TLC. After the reaction, water (10 L) and toluene (10 L) were added and stirred for 0.5 h to separate the solution. The organic layer was successively washed with 5% NaOH (15 L), water (20 L), 5% hydrochloric acid (15 L) and water (20 L). The organic layer was added with activated carbon (250.0 g) and stirred at room temperature for 1 hour. After vacuum filtration, the filtrate was concentrated under reduced pressure at 60° C. to obtain compound 5 which was a brown oil (8.10 kg). The product was directly put into the next reaction without further purification.
1H NMR (500 MHz, Chloroform-d) δ 7.39-7.27 (m, 5H), 5.19 (d, J=1.3 Hz, 1H), 5.17-5.07 (m, 2.6H), 5.02 (s, 0.4H), 4.27-3.89 (m, 5H), 3.68-3.56 (m, 1H), 3.23-3.10 (m, 1.6H), 3.02-2.90 (m, 1.4H), 2.47-2.26 (m, 2H), 1.99-1.90 (m, 2H), 1.27-1.17 (m, 4.8H), 1.13 (t, J=7.2 Hz, 1.2H).
13C NMR (126 MHz, Chloroform-d) δ 173.3, 173.2, 170.3, 170.2, 155.6, 138.8, 138.4, 136.7, 136.2, 128.7, 128.6, 128.4, 128.2, 127.9, 116.3, 116.0, 67.6, 67.4, 61.7, 60.5, 59.6, 58.7, 49.2, 48.9, 40.5, 39.4, 31.6, 31.4, 24.2, 23.7, 14.4, 14.14, 14.07.
HRMS (m/z): calc. for C21H29ClNO6 [M+H]+=426.1683; found, 426.1678
Step (e): At room temperature and under the protection of nitrogen, sodium tert-butoxide (3.31 kg, 34.53 mol) and anhydrous tetrahydrofuran (38L) were added into a 100 L reaction kettle and stirred, then cooled to below −5° C. The compound of Formula 5 (8.10 kg, 17.26 mol) was dissolved in tetrahydrofuran (15 L) and then added dropwise into the reaction kettle. The temperature during the dripping process was controlled not to exceed 0° C. and complete dripping within 4-5 hours. Continued stirring at 0° C.-5° C. after the dripping process and the reaction was monitored by HPLC. After the end of the reaction, dilute hydrochloric acid was added to the kettle to adjust the solution to pH5-6, then ethyl acetate (10 L) was added, and stirred at room temperature to divide the solution. The organic layer was washed with saturated sodium chloride (20 L×2), and the aqueous layer is extracted once with ethyl acetate (10 L). Then the organic layer was combined, and activated carbon (500 g) was added and stirred for 1 hour at room temperature. After vacuum filtration, the filtrate was concentrated under reduced pressure to obtain compound of Formula 6 which is a light brown oil (5.44 kg, yield of two steps is 83%).
1H NMR (500 MHz, Chloroform-d) δ 12.23 (s, 1H), 7.41-7.28 (m, 5H), 5.27-5.05 (m, 4H), 5.01 (s, 0.4H), 4.94-4.82 (m, 0.6H), 4.30 (dd, J=13.6, 5.7 Hz, 0.6H), 4.23 (q, J=7.1 Hz, 2H), 4.19-4.12 (m, 0.4H), 3.09-2.66 (m, 3H), 2.46-2.23 (m, 2H), 1.30 (t, J=7.1 Hz, 3H).
13C NMR (126 MHz, Chloroform-d) δ 172.0, 171.9, 168.8, 168.2, 155.2, 155.1, 138.4, 138.3, 136.7, 136.3, 128.5, 128.2, 128.0, 115.8, 115.6, 97.7, 97.4, 67.7, 67.5, 61.0, 52.7, 52.5, 41.5, 40.7, 38.2, 37.3, 22.8, 22.3, 14.3.
HRMS (m/z): calc. for C19H23ClNO5 [M+H]+=380.1265; found, 380.1266
Note: in step (d), the yield exceeded the theoretical value. Therefore, according to the 100% yield, the mole number of the compound of Formula 5 was 17.26 mol.
Step (f): Compound of Formula 6 (5.44 kg, 14.33 mol), DMF (16.3 L), water (2.7 L) and lithium chloride (0.61 kg, 14.33 mol) were added into a 50 L reaction kettle at room temperature and stirred. The reaction mixture was stirred and heated to 120° C., and the reaction was monitored by HPLC. After the end of the reaction, the reaction mixture was cooled to 20-25° C. Water (25 L) and methyl tert-butyl ether (30 L) were added, stirred and separated. The organic layer was washed with water (25 L×2) and separated, then the generated aqueous layer was extracted with methyl tert-butyl ether (25 L). By combining the organic layers and concentrating under reduced pressure at 45° C., compound of Formula 7 (4.19 kg, yield 95%) was obtained, which was a brown oil.
1H NMR (500 MHz, Chloroform-d) δ 7.40-7.29 (m, 5H), 5.32-5.03 (m, 4H), 4.86 (s, 1H), 4.34-3.98 (m, 1H), 3.23 (s, 1H), 2.94-2.59 (m, 2H), 2.59-2.39 (m, 2H), 2.05 (s, 1H), 2.01-1.92 (m, 1H).
13C NMR (126 MHz, Chloroform-d) δ 206.7, 155.5, 128.6, 128.3, 116.1, 67.8, 61.8, 37.1, 22.5.
HRMS (m/z): calc. for C16H19ClNO3 [M+H]+=308.1053; found, 308.1057
Preparation of Intermediate Compound of Formula 8 (R3=Cbz)
Step (g): Anhydrous ethanol (18 L) and sodium borohydride (0.51 kg, 13.61 mol) were added into a 50 L reaction kettle at room temperature and stirred, then cooled to 5-10° C. Compound of Formula 7 (4.19 kg, 13.61 mol) was dissolved in anhydrous ethanol (9 L) and added dropwise into the reactor under the temperature controlled not to exceed 10° C. Keep stirring at 5-10° C. The reaction was monitored by HPLC. After the end of the reaction, water (20 L) was added dropwise into the kettle. After the dripping process, methyl tert-butyl ether (25 L) was added, stirred and separated. The organic layer was washed sequentially with 10% NaOH (10 L), 5% hydrochloric acid (10 L×2) and Water (10 L). The generated aqueous layer was extracted with methyl tert-butyl ether (25 L). The organic layers were combined, and added with activated carbon (500 g) and stirred at room temperature for 1 hour. After filtration, the filtrate was concentrated under reduced pressure at 45° C. to obtain the compound of Formula 8 (3.50 kg, yield 83%), which was a brown oil.
1H NMR (500 MHz, Chloroform-d) δ 7.42 — 7.27 (m, 5H), 5.21-5.06 (m, 4H), 4.76 (s, 1H), 4.05 (d, J=14.0 Hz, 1H), 3.92-3.79 (m, 1H), 2.84-2.60 (m, 3H), 1.87-1.76 (m, 1H), 1.76-1.65 (m, 1H), 1.58-1.42 (m, 2H).
13C NMR (126 MHz, Chloroform-d) δ 155.8, 139.8, 136.7, 128.5, 128.2, 128.1, 114.5, 68.7, 67.5, 54.2, 37.9, 33.5, 27.9, 24.3.
HRMS (m/z): calc. for C16H21ClNO3 [M+H]+=310.1210; found, 310.1208
Step (h): Compound of Formula 8 (3.55 kg, 12.36 mol), hydrochloric acid (6 mol/L, 18.83 l, 112.98 mol) and ethanol (20 L) were added into a 50 L reaction kettle at room temperature, stirred and heated for reflux reaction and the reaction was monitored by HPLC. After the reaction was completed, the reaction solution was cooled to 50-55° C. and concentrated under reduced pressure to remove ethanol. The remaining liquid was added with methyl tert-butyl ether (20 L×2), stirred and separated. The aqueous layer was adjusted to pH>11 with 40% sodium hydroxide, and then added ethyl acetate (20 L×2) for extraction. The organic layers were combined, and added with anhydrous magnesium sulfate and dried. After filtration, the filtrate was concentrated under reduced pressure to obtain the crude product. Acetonitrile (5 L) was added to the crude product, stirred to dissolve at 70° C., and then the product was crystallized at room temperature. After filtration and vacuum drying, compound of Formula 9 (1.01 kg, yield 50.7%) was obtained, which was a nearly white solid.
1H NMR (500 MHz, Chloroform-d) δ 5.25 (d, J=1.1 Hz, 1H), 5.23 (t, J=1.0 Hz, 1H), 3.65 (S, 1H), 3.03 (ddt, J=11.5, 4.3, 2.0 Hz, 1H), 2.88 (ddd, J=7.5, 6.3, 1.4 Hz, 1H), 2.65 (td, J=11.9, 2.9 Hz, 1H), 2.49 (d, J=6.8 Hz, 2H), 1.91 (dtt, J=13.4, 4.0, 2.0 Hz, 1H), 1.73 (qt, J=13.1, 4.3 Hz, 1H), 1.54 (tdd, J=13.3, 4.7, 2.5 Hz, 1H), 1.45 (ddq, J=12.9, 4.9, 2.6 Hz, 1H).
13C NMR (126 MHz, Chloroform-d) δ 139.8, 115.2, 67.1, 57.7, 47.2, 43.0, 32.2, 20.4.
HRMS (m/z): calc. for C8H15ClNO [M+H]+=176.0842; found, 176.0837
Step (i): Compound of Formula 9 (1 kg, 5.69 mol), 1,4-dioxane (5 L), water (5 L), sodium carbonate (0.91 kg, 8.54 mol) were added into a 50 L reaction kettle at room temperature, stirred and cooled to 5-10° C. 9-fluorenylmethyl chloroformate (1.47 kg, 5.69 mol) was dissolved in 1,4-dioxane (2 L) and then added dropwise into the reaction kettle, with the temperature controlled not to exceed 20° C. After the dripping process, stirred to continue the reaction at room temperature, monitored by TLC. After the end of the reaction, ethyl acetate (20 L) and water (20 L) were added and stirred, then the solution was separated. The organic layer was washed with saturated sodium chloride (5 L×2) and separated. The aqueous layer was extracted once with ethyl acetate (10 L). The organic layers were combined, added with activated carbon (500 g) at room temperature and stirred for 1 hour. After filtration, the filtrate was concentrated to produce compound of Formula 10, which was a yellowish thick substance (2.81 kg). The product did not need for further purification and was directly put into the next reaction.
1H NMR (500 MHz, Chloroform-d) δ 7.81-7.71 (m, 2H), 7.65-7.53 (m, 2H), 7.40 (td, J=7.5, 2.4 Hz, 2H), 7.31 (t, J=7.4 Hz, 2H), 5.17 (s, 1H), 5.14 (s, 1H), 4.93-4.51 (m, 1H), 4.49 (dd, J=10.7, 6.7 Hz, 1H), 4.41 (dd, J=10.7, 6.5 Hz, 1H), 4.25 (t, J=6.5 Hz, 1H), 3.92 (s, 1H), 3.76 (s, 1H), 2.85-2.54 (m, 3H), 1.87-1.74 (m, 1H), 1.73-1.58 (m, 1H), 1.57-1.33 (m, 2H).
13C NMR (126 MHz, Chloroform-d) δ 155.8, 144.1, 141.5, 141.4, 139.8, 127.73, 127.70, 127.15, 127.10, 125.09, 125.06, 120.02, 119.99, 114.4, 68.4, 67.5, 54.3, 47.5, 37.9, 33.3, 27.7, 24.2.
HRMS (m/z): calc. for C23H25ClNO3 [M+H]+=398.1523; found, 398.1530
Step (j): Compound of Formula 10 (2.81 kg, 5.69 mol), acetonitrile (10 L) and water (5 L) were added into a 50 L reaction kettle at room temperature, stirred and cooled to 0-5° C. N-bromosuccinimide (1.01 kg, 5.69 mol) was added into the kettle in batches, and the temperature was controlled not to exceed 5° C. After it was completed, stirred to continue the reaction at 0-5° C. and the reaction was monitored by HPLC. After the end of the reaction, 10% sodium sulfite solution (10 L) was added and stirred for 0.5 h. Ethyl acetate (10 L×2) was added for extraction and separation. The organic layer is washed with saturated sodium bicarbonate (5 L) and saturated sodium chloride (5 L×2) and separated. The organic layer was added with activated carbon (320 g) and stirred at room temperature for 1 hour, then anhydrous magnesium sulfate was added and stirred for 0.5 hours. After filtration, the filtrate was concentrated under reduced pressure to obtain compound of Formula 11, which was a dense substance (2.85 kg). The product was directly put into the next reaction without further purification.
Note: in step (i), the yield exceeded the theoretical value. Therefore, according to the 100% yield, the mole number of the compound of Formula 10 was 5.69 mol.
Step (k): Compound of Formula 12 (1.40 kg, 5.41 mol), lithium hydroxide (0.15 kg, 6.26 mol) and N,N-dimethylformamide (28 L) were added into a 100 L reactor at room temperature, and then the mixture was stirred at room temperature for 1 hour, then cooled to 0-5° C. Compound of Formula 11 (2.85 kg, 5.69 mol) was dissolved in N,N-dimethylformamide (2.8 L) and then added dropwise into the reactor with temperature controlled not to exceed 5° C. the dripping process completed within 4-5 hours. The reaction was monitored by HPLC. After the reaction was completed, diethylamine (1 L) was added into the reactor and stirred at 0° C.-5° C.
The reaction was monitored by HPLC. After the reaction was completed, water (25 L) and ethyl acetate (30 L) were added into the reactor, then the liquid was separated by stirring. The aqueous layer was extracted by ethyl acetate (20 L×3). The organic layers were combined and concentrated at 50° C. under reduced pressure. The concentrated residue was added with 85% lactic acid solution (1.5 kg), stirred at room temperature for 1 hour, and then added with methyl tert- butyl ether (10 L×2) for extraction The aqueous layer was added with potassium carbonate to adjust to pH 8-9. Then ethyl acetate (15 L×3) was added and the organic layer was combined and concentrated at 45-50° C. under reduced pressure to produce the crude product, which was added with ethyl acetate (8 L) and stirred at room temperature for 0.5 h. After filtration, the filter cake was vacuum dried to obtain Compound of Formula 13 (1.84 kg, 3-step yield 78%), which was a white solid.
1H NMR (400 MHz, Chloroform-d) δ 8.32 (s, 1H), 8.26 (s, 1H), 7.98 (s, 1H), 4.34 (d, J=13.9 Hz, 1H), 4.16 (d, J=13.9 Hz, 1H), 3.88 (t, J=3.1 Hz, 1H), 3.29 (t, J=3.4 Hz, 1H), 2.97 (d, J=10.9 Hz, 1H), 2.52 (t, J=11.8 Hz, 1H), 2.10 (d, J=15.1 Hz, 1H), 2.03 (dd, J=13.1, 3.7 Hz, 2H), 1.83 (d, J=13.2 Hz, 1H), 1.81-1.72 (m, 1H), 1.54 (ddt, J=15.0, 12.0, 3.4 Hz, 2H).
13C NMR (126 MHz, Chloroform-d) δ 160.1, 149.5, 147.2, 133.4, 132.7, 129.4, 127.9, 122.1, 105.3, 78.0, 55.8, 50.3, 44.67, 43.7, 26.9, 20.2.
HRMS (m/z): calc. for C16H18BrClN3O3 [M+H]+=414.0220/416.0200; found, 414.0216/416.0197
Note: in step (i) and (j), the calculated yield exceeded the theoretical value. Therefore, according to the 100% yield, the mole number of compound of Formula 11 was 5.69 mol.
Step (1): Compound of Formula 13 (1.84 kg, 4.43 mol) and anhydrous ethanol (20 L) were added into a 50 L reaction kettle at room temperature, stirred and heated to reflux reaction, and the reaction was monitored by HPLC. After the reaction, the reaction liquid was cooled to 55-60° C. After vacuum filtration, the filter cake was washed with ethanol and vacuum dried to obtain Compound of Formula 1, which was a white solid (1.31 kg, yield 71.2%, HPLC purity 98.6%).
1H NMR (400 MHz, DMSO-d6) δ 8.23 (s, 1H), 8.22 (s, 1H), 8.15 (s, 1H), 4.99 (d, J=2.8 Hz, 2H), 4.79 (d, J=5.8 Hz, 1H), 2.98 (dt, J=15.3, 4.7 Hz, 2H), 2.78 (d, J=12.3 Hz, 1H), 2.64 (td, J=8.9, 3.8 Hz, 1H), 2.44 (dd, J=15.5, 8.7 Hz, 1H), 2.36 (td, J=12.1, 2.7 Hz, 1H), 1.95-1.83 (m, 1H), 1.56 (dt, J=13.3, 3.2 Hz, 1H), 1.34 (qt, J=12.4, 3.7 Hz, 1H), 1.28-1.13 (m, 1H).
13C NMR (126 MHz, DMSO-d6) δ 200.7, 158.6, 149.5, 147.2, 132.4, 131.8, 128.4, 126.8, 121.7, 66.7, 56.2, 54.4, 43.0, 30.5, 20.1.
HRMS (m/z): calc. for C16H18BrClN3O3 [M+H]+=414.0220/416.0200; found, 414.0214/416.0195
Step (i): Compound of Formula 9 (0.7 kg, 3.98 mol), 1,4-dioxane (3.5 L), water (3.5 L), sodium carbonate (0.63 kg, 5.98 mol) were added into a 50 L reaction kettle at room temperature, stirred and cooled to 5-10° C. Chloroformate-9-fluorene methyl ester (1.03 kg, 3.98 mol) was dissolved in 1,4-dioxane (1.4 L) and then added dropwise into the reaction kettle, with the temperature controlled not to exceed 20° C. After the dripping process, stirred to continue the reaction at room temperature, monitored by TLC. After the end of the reaction, ethyl acetate (15 L) and water (15 L) were added and stirred, then the solution was separated. The organic layer was washed with saturated sodium chloride (3 L×2) and separated. The aqueous layer was extracted once with ethyl acetate (8 L). The organic layers were combined, added with activated carbon (300 g) at room temperature and stirred for 1 hour. After filtration, the filtrate was concentrated to produce compound of Formula 10, which was a yellowish thick substance (1.81 kg). The product did not need further purification and was directly put into the next reaction.
Step (j): Compound of Formula 10 (1.81 kg, 3.98 mol), acetonitrile (7 L) and water (3.5 L) were added into a 50 L reaction kettle at room temperature, stirred and cooled to 0-5° C. N-bromosuccinimide (0.71 kg, 3.98 mol) was added into the kettle in batches, and the temperature was controlled not to exceed 5° C. After it was completed, stirred to continue the reaction at 0-5° C. and monitored by HPLC. After the reaction, 10% sodium sulfite solution (7 L) was added and stirred for 0.5 h. Ethyl acetate (7 L×2) was added to extraction and separation. The organic layer is washed with saturated sodium bicarbonate (3 L) and saturated sodium chloride (3 L×2) and separated. The organic layer was added with activated carbon (200 g) and stirred at room temperature for 1 hour, then anhydrous magnesium sulfate was added and stirred for 0.5 hours. After filtration, the filtrate was concentrated under reduced pressure to obtain compound of Formula 11, which was a dense substance (1.85 kg). The product was directly put into the next reaction without further purification.
Note: in step (i), the yield exceeded the theoretical value. Therefore, according to the 100% yield, the mole number of the compound of Formula 10 was 3.98 mol.
Step (k): Compound of Formula 12 (0.98 kg, 3.79 mol), lithium hydroxide (100 g, 4.38 mol) and N,N-dimethylformamide (20 L) were added into a 100 L reactor at room temperature, and then the mixture was stirred at room temperature for 1 hour, then cooled to 0-5° C. Compound of Formula 11 (1.85 kg, 3.98 mol) was dissolved in N,N-dimethylformamide (2 L) and then added dropwise into the reactor with temperature controlled not to exceed 5° C., the dripping process completed within 4-5 hours. The reaction was monitored by HPLC. After the reaction was completed, diethylamine (0.7 L) was added into the reactor and stirred at 0-5° C. . The reaction was monitored by HPLC. After the reaction was completed, water (16 L) and ethyl acetate (20 L) were added into the reactor, then the liquid was separated by stirring. The aqueous layer was extracted by ethyl acetate (15 L×3). The organic layers were combined and concentrated at 50° C. The concentrated residue was added with 85% lactic acid solution (1.05 kg), stirred at room temperature for 1 hour, and then added with methyl tert-butyl ether (8 L×2) for extraction. The aqueous layer was added with potassium carbonate to adjust to pH 8-9. Then ethyl acetate (10 L×3) was added and the organic layer was combined and concentrated at 45-50° C. under reduced pressure to produce the crude product, which was added with ethyl acetate (5 L) and stirred at room temperature for 0.5 h. After filtration, the filter cake was vacuum dried to obtain Compound of Formula 13 (1.31 kg, 3-step yield 79%), which was a white solid.
Note: in step (i) and (j), the yield exceeded the theoretical value. Therefore, according to the 100% yield, the mole number of the compound of Formula 11 was 3.98 mol.
Step (1): Compound of Formula 13 (1.31 kg, 3.16 mol) and anhydrous ethanol (16 L) were added into a 50 L reaction kettle at room temperature, stirred and heated to reflux reaction, and the reaction was monitored by HPLC. After the end of the reaction, the reaction liquid was cooled to 55-60° C. After vacuum filtration, the filter cake was washed with ethanol and vacuum dried to obrain Compound of Formula 1, which was a white solid (0.91 kg, yield 70%, HPLC purity 98.4%).
Step (a): At room temperature, diethyl acetylaminomalonic acid (2.50 kg, 11.51 mol), anhydrous potassium carbonate (3.18 kg, 23.02 mol), potassium iodide (0.38 kg, 2.3 mol), tetrabutylammonium bromide (0.19 kg, 0.58 mol) and acetonitrile (13 L) were added into a 50 L reaction kettle. After being stirred for 20 minutes, 2,3-dichloropropene (1.53 kg,13.81 mol) was added. The reaction was carried out at 85-90° C. and monitored by HPLC. After the end of the reaction, the reaction mixture was cooled to a temperature within 25° C., and diluted hydrochloric acid was added dropwise into the reactor to neutralize the reaction mixture to pH 7-7.5. The reaction solution was left to separation, then the organic layer was concentrated under reduced pressure at 50° C. The concentrated residue was added with ethanol water (1:10, 10 L) and stirred for 1 hour for crystallization. After vacuum filtration, the filter cake was washed with water to obtain compound of Formula 2, which was a yellow solid (wet weight 5.82 kg), which was not dried and directly put into the next reaction.
Step (b): At room temperature, the compound of Formula 2 (wet weight 5.82 kg, 11.5 lmol) and hydrochloric acid solution (6 mol/L, 30 L, 180 mol) were added into a 100 L reaction kettle, stirred and heated to 100° C. for reflux reaction, and the reaction was monitored by TLC. After the end of the reaction, the reaction kettle was added with activated carbon (250 g) and cooled to not to exceed 50° C. After vacuum filtration, the filter cake was washed with water, then the filtrate was combined and concentrated under reduced pressure at 80-85° C. to remove the solvent to obtain compound of Formula 3, which was a light-yellow solid (2.05 kg). The product was directly put into the next reaction without further purification.
Step (c): At room temperature, compound of Formula 3 (2.05 kg, 11.02 mol), diethyl carbonate (6 L) and anhydrous ethanol (2 L) were added into a 50 L reaction kettle and stirred.
Concentrated sulfuric acid (0.56 kg, 5.75 mol) was added dropwise and completed within 20-30 minutes. Then, heated to 85-95° C. for reflux reaction, and the reaction was monitored by HPLC. After the end of the reaction, the reaction solution was cooled to 50-60° C. and concentrated under reduced pressure, and the remaining liquid was diluted with water and cooled to not to exceed 10° C. 30% sodium hydroxide was added dropwise to adjust the solution to pH 8-9, then moved to room temperature for extraction using dichloromethane (5 L×3). After extraction, the organic layers were combined, added with anhydrous sodium sulfate and dried. After vacuum filtration, the filtrate was concentrated at 40° C. to obtain compound of Formula 4, which was a light brown oil (1.59 kg, The total yield of 3 steps is 78%).
Note: in step (a), the product was wet without being dried, so the yield exceeded the theoretical value. Therefore, according to the 100% yield, the mole number of the compound of Formula 2 was 11.51 mol.
Preparation of Intermediate Compound of Formula 6 (R1=Et; R2=Et; R3=Cbz)
Step (d): At room temperature, compound of Formula 4 (1.50 kg, 8.44 mol), anhydrous sodium carbonate (2.69 kg, 25.33 mol), tetrabutylammonium iodide (0.31 kg, 0.84 mol) and toluene (4.5 L) were added into a 50 L reaction kettle, and toluene (3 L) solution of ethyl 4-bromobutyrate (1.65 kg, 8.44 mol) was added after stirring for 20 minutes. The reaction was stirred at 75-80° C. and monitored by HPLC. After the end of the reaction, the temperature was cooled to 20-25° C. Water (5 L) was added and stirred for 10-15 minutes, then benzyl chloroformate (1.44 kg, 8.44 mol) was added dropwise and completed within about 2-3 hours. The reaction was continuously stirred at 20-25° C. and monitored by TLC. After the reaction, water (5 L) and toluene (5 L) were added and stirred for 0.5 h to separate the solution. The organic layer was successively washed with 5% NaOH (10 L), water (10 L), 5% hydrochloric acid (15 L) and water (10 L). The organic layer was added with activated carbon (100.0 g) and stirred at room temperature for 1 hour. After vacuum filtration, the filtrate was concentrated under reduced pressure at 60° C. to obtain compound of Formula 5 which was a brown oil (4.18 kg). The product was directly put into the next reaction without further purification.
Step (e): At room temperature and under the protection of nitrogen, sodium tert-butoxide (1.62 kg, 16.89 mol) and anhydrous tetrahydrofuran (19 L) were added into a 100 L reaction kettle and stirred, then cooled to below −5° C. The compound of Formula 5 (4.18 kg, 8.44 mol) was dissolved in tetrahydrofuran (8 L) and then added dropwise into the reaction kettle. The temperature during the dripping process was controlled not to exceed 0° C. and completed dripping within 4-5 hours. Continued stirring at 0-5° C. after the dripping process and the reaction was monitored by HPLC. After the end of the reaction, dilute hydrochloric acid was added to the kettle to adjust the solution to pH5-6. Ethyl acetate (5 L) was added, and stirred at room temperature to divide the solution. The organic layer was washed with saturated sodium chloride (10 L×2), and the aqueous layer was extracted once with ethyl acetate (5 L). The organic layer was combined and added with activated carbon (200 g) and stirred for 1 hour at room temperature. After vacuum filtration, the filtrate was concentrated under reduced pressure to obtain compound of Formula 6, which was a light brown oil (2.73 kg, The total yield of two steps is 85%).
Note: in step (d), the yield exceeded the theoretical value. Therefore, according to the 100% yield, the mole number of the compound of Formula 5 was 8.44 mol.
Step (f): Compound of Formula 6 (2.00 kg, 5.27 mol), DMF (6 l), water (1 L) and lithium chloride (0.22 kg, 2.27 mol) were added into a 50 L reaction kettle at room temperature and stirred. The reaction mixture was stirred and heated to 120° C. and the reaction was monitored by HPLC. After the end of the reaction, the reaction mixture was cooled to 20-25° C. Water (12 L) and methyl tert-butyl ether (15 L) were added, stirred and separated. The organic layer was washed with water (15 L×2) and separated, then the generated aqueous layer was extracted with methyl tert-butyl ether (15 L). By combining the organic layers and concentrating under reduced pressure at 45° C., compound of Formula 7 (1.52 kg, yield 94%) was obtained, which was a brown oil.
Step (g): Anhydrous ethanol (7 L) and sodium borohydride (0.19 kg, 4.95 mol) were added into a 50 L reaction kettle at room temperature and stirred, then cooled to 5-10° C. Compound of Formula 7 (1.52 kg, 4.95 mol) was dissolved in anhydrous ethanol (3 L) and added dropwise into the reactor under the temperature controlled not to exceed 10° C. Keep stirring at 5-10° C. The reaction was monitored by HPLC. After the end of the reaction, water (10 L) was added dropwise into the kettle. After the dripping process, methyl tert-butyl ether (10 L) was added, stirred and separated. The organic layer was washed sequentially with 10% NaOH (5 L), 5% hydrochloric acid (5 L×2) and Water (5 L). The generated aqueous layer was extracted with methyl tert-butyl ether (15 L). The organic layers were combined, and added with activated carbon (200 g) and stirred at room temperature for 1 hour. After filtration, the filtrate was concentrated under reduced pressure at 45° C. to obtain the compound of Formula 8 (1.30 kg, yield 85%), which was a brown oil.
Step (h): Compound of Formula 8 (1.30 kg, 4.21 mol), hydrochloric acid (6 mol/L, 5.61 L, 33.68 mol) and ethanol (6 L) were added into a 50 L reaction kettle at room temperature, stirred and heated for reflux reaction and the reaction was monitored by HPLC. After the reaction was completed, the reaction solution was cooled to 50-55° C. and concentrated under reduced pressure to remove ethanol. The remaining liquid was added with methyl tert-butyl ether (7 L×2), stirred and separated. The aqueous layer was adjusted to pH>11 with 40% sodium hydroxide, and then added with ethyl acetate (10 L)×2) for extraction. The organic layers were combined, added with anhydrous magnesium sulfate and dried. After filtration, the filtrate was concentrated under reduced pressure to obtain the crude product. Acetonitrile (2 L) was added to the crude product, stirred to dissolve at 70° C., and then the product was crystallized at room temperature. After filtration and vacuum drying, compound of Formula 9 (0.35 kg, yield 48%) was obtained, which was a nearly white solid.
Synthesis of Halofuginone Hydrobromate (Compound of Formula 1)
Hydrobromate (100 g, 0.24 mol) and hydrobromic acid solution (4.8%, 700 ml) were added into a 1 L glass reaction flask at room temperature, and stirred for 2 hours. After decompression filtration, the filter cake was washed with pure water and dried in vacuum to obtain halofuginone hydrobromate, which was a white solid (118 g, yield 99%, HPLC purity 98.6%).
Halofuginone (100 g, 0.24 mol), pure water (400 ml) and DL-lactic acid (85% aqueous solution, 25.6 g, 0.24 mol) were added into a 500 mL glass reaction flask at room temperature. After being stirred and dissolved, the reaction solution was concentrated to remove water at 60° C. under reduced pressure. After concentration, the remaining liquid was added with ethanol (500 mL) and stirred at 0° C. for crystallization. After filtration under reduced pressure, the filter cake was dried in vacuum to obtain the lactate of halofuginone, which was a white solid (84 g, yield 70%, HPLC purity 99.2%).
Synthesis of Compound of Formula (+)-9(dextro optically active [(+)-(2S, 3S)-2-(2-chloropropenyl)-3-hydroxypiperidine])
Step (1): Racemic compound of Formula 9 (140 g, 0.797 mol, prepared according to the method of embodiment 1) and acetonitrile (1400 mL) were added into a 5 L three-mouth bottle at room temperature, heated to 60° C. and stirred to dissolve. L-(−)-dibenzoyl tartaric acid (300 g, 0.837 mol) of Formula 15 was dissolved in acetonitrile (800 mL), and then added dropwise to the reaction flask. The dripping process was completed within about 10 min, continued stirring for 20-30 minutes. Then the bottle was moved to room temperature and stirred for 2 hours. After filtration, the filter was washed with acetonitrile (300 mL) and drain to obtain crude compound salt, which was added with pure water and acetonitrile (1:4, 2000 mL), stirred and heated to 80° C. to dissolve, filtered while hot, and the filtrate was stirred at room temperature for 2 hours for crystallization. The compound of Formula 14 (136 g, yield 32%) was obtained by filtration, acetonitrile leaching and drying.
Step (2): At room temperature, compound of Formula 14 (136 g), pure water (700 mL) and ethyl acetate (700 mL) were added into a 5 L three-mouth flask, stirred, and 1 mol/L NaOH was added dropwise to adjust to pH 12-14. The aqueous layer was separated with ethyl acetate (700 mL×2). After extraction, organic layers were combined, added anhydrous MgSO4 to dry. After filtration, and the filtrate was concentrated at 50° C. under reduced pressure to obtain compound (+)-9, which wasa white solid (44 g, yield 98%).
[α]D=+8.43° (c=0.46, MeOH)
1H NMR (500 MHz, Chloroform-d) δ 5.25 (d, J=1.1 Hz, 1H), 5.23 (t, J=1.0 Hz, 1H), 3.65 (S, 1H), 3.03 (ddt, J=11.5, 4.3, 2.0 Hz, 1H), 2.88 (ddd, J=7.5, 6.3, 1.4 Hz, 1H), 2.65 (td, J=11.9, 2.9 Hz, 1H), 2.49 (d, J=6.8 Hz, 2H), 1.91 (dtt, J=13.4, 4.0, 2.0 Hz, 1H), 1.73 (qt, J=13.1, 4.3 Hz, 1H), 1.54 (tdd, J=13.3, 4.7, 2.5 Hz, 1H), 1.45 (ddq, J=12.9, 4.9, 2.6 Hz, 1H).
13C NMR (126 MHz, Chloroform-d) δ 139.8, 115.2, 67.1, 57.7, 47.2, 43.0, 32.2, 20.4.
HRMS (m/z): calc. for C8H15ClNO [M+H]+=176.0842; found, 176.0837
Synthesis of Compound of Formula (−)-9(I-optically active [(−)-(2R,3R)-2-(2-chloropropenyl)-3-hydroxypiperidine)]
Step (1): Racemic compound of Formula 9 (14 g, 79.7 mmol, prepared according to the method of embodiment 1) and acetonitrile (140 ml) were added into a 5 L three-mouth bottle at room temperature, heated to 60° C. and stirred to dissolve. L-(−)-dibenzoyl tartaric acid (30 g, 83.7 mmol) of Formula 16 is dissolved in acetonitrile (80 mL), and then added dropwise into the reaction flask. The dripping process was completed within about 10 min, continued stirring for 20-30 minutes. Then the bottle was moved to room temperature and stirred for 2 hours. After filtration, the filter was washed with acetonitrile (30 mL) and drain to obtain crude compound salt, which was added with pure water and acetonitrile (1:4, 200 mL), stirred and heated to 80° C. to dissolve, filtered while hot, and the filtrate was stirred at room temperature for 2 hours for crystallization. The compound of Formula 17 (12.1 g, yield 28.4%) was obtained by filtration, acetonitrile leaching and drying.
Step (2): At room temperature, compound of Formula 17 (12.1 g), pure water (70 mL) and ethyl acetate (100 mL) were added into a 5 L three-mouth flask, stirred, and 1 mol/L NaOH was added dropwise to adjust to pH 12-14. The aqueous layer was separated with ethyl acetate (100 ml×2). After extraction, organic layers were combined, added anhydrous MgSO4 to dry. After filtration, the filtrate was concentrated at 50° C. under reduced pressure to obtain compound (−)-9, which was a white solid (3.7 g, yield 93.1%).
[α]D=−8.43° (c=0.46, MeOH)
1H NMR (500 MHz, Chloroform-d) δ 5.25 (d, J=1.1 Hz, 1H), 5.23 (t, J=1.0 Hz, 1H), 3.65 (S, 1H), 3.03 (ddt, J=11.5, 4.3, 2.0 Hz, 1H), 2.88 (ddd, J=7.5, 6.3, 1.4 Hz, 1H), 2.65 (td, J=11.9, 2.9 Hz, 1H), 2.49 (d, J=6.8 Hz, 2H)., 1.91 (dtt, J=13.4, 4.0, 2.0 Hz, 1H), 1.73 (qt, J=13.1, 4.3 Hz, 1H), 1.54 (tdd, J=13.3, 4.7, 2.5 Hz, 1H), 1.45 (ddq, J=12.9, 4.9, 2.6 Hz, 1H).
13C NMR (126 MHz, Chloroform-d) δ 139.8, 115.2, 67.1, 57.7, 47.2, 43.0, 32.2, 20.4.
HRMS (m/z): calc. for C8H15ClNO [M+H]+=176.0842; found, 176.0837
Synthesis of Compound of Formula (+)-1, namely (+)-halofuginone (d-halofuginone)
Step (3): Compound (+)-9 (10 g, 56.9 mmol), 1,4-dioxane (50 mL), water (50 mL) and sodium carbonate (9.1 g, 85.4 mmol) were added into a 500 mL reaction flask at room temperature, stirred and cooled to 5-10° C. 9-fluorenylmethyl chloroformate (14.7 g, 56.9 mmol) was dissolved in 1,4-dioxane (20 mL) and then added dropwise to the reaction flask with the temperature controlled not to exceed 20° C. The reaction was continued at room temperature and monitored by TLC. After the reaction, ethyl acetate (200 mL) and water (200 mL) were added. The reaction solution was stirred and separated. The organic layer was washed with Saturated sodium chloride (50 mL×2) and separated. The aqueous layer was extracted once with ethyl acetate (100 mL). The organic layers were combined, added with activated carbon (5 g) and stirred at room temperature for 1 hour. After filtration, the filtrate was concentrated under reduced pressure to obtain compound of Formula (+)-10, which was a light yellow consistency (25.1 g, EE=96%). The product was directly put into the next reaction without further purification.
[α]D=+25.42° (c=0.35, CHCl3)
1H NMR (500 MHz, Chloroform-d) δ 7.81-7.71 (m, 2H), 7.65-7.53 (m, 2H), 7.40 (td, J=7.5, 2.4 Hz, 2H), 7.31 (t, J=7.4 Hz, 2H), 5.17 (s, 1H), 5.14 (s, 1H), 4.93-4.51 (m, 1H), 4.49 (dd, J=10.7, 6.7 Hz, 1H), 4.41 (dd, J=10.7, 6.5 Hz, 1H), 4.25 (t, J=6.5 Hz, 1H), 3.92 (s, 1H), 3.76 (s, 1H), 2.85-2.54 (m, 3H), 1.87-1.74 (m, 1H), 1.73-1.58 (m, 1H), 1.57-1.33 (m, 2H).
13C NMR (126 MHz, Chloroform-d) δ 155.8, 144.1, 141.5, 141.4, 139.8, 127.73, 127.70, 127.15, 127.10, 125.09, 125.06, 120.02, 119.99, 114.4, 68.4, 67.5, 54.3, 47.5, 37.9, 33.3, 27.7, 24.2.
HRMS (m/z): calc. for C23H25ClNO3 [M+H]+=398.1523; found, 398.1530
Step (4): Compound of Formula (+)-10 (28 g, 56.9 mol), acetonitrile (100 mL) and water (50 mL) were added into a 500 ml reaction flask at room temperature, stirred and cooled to 0° C.-5° C. N-bromosuccinimide (10.1 g, 56.9 mol) was added into the reaction flask in batches with the temperature controlled not to exceed 5° C. After the dripping process, stirred to continue the reaction at 0-5° C. and monitored by HPLC. After the reaction, 10% sodium sulfite solution (100 mL) was added and stirred for 0.5 h. Then ethyl acetate (100 mL×2) was added for extraction and separation. The organic layer was washed with saturated sodium bicarbonate (50 mL) and saturated sodium chloride (50 mL×2) and separated. After the organic layer was added with activated carbon (5 g) and stirred at room temperature for 1 hour, anhydrous magnesium sulfate was added and stirred for 0.5 hours. After filtration, the filtrate was concentrated under reduced pressure to obtain compound of Formula (+)-11 [27.5 g, [α]D=+36.66° (c=0.30, CHCl3)], which was a thick substance. The product was directly put into the next step without further purification.
Step (5): Compound of Formula 12 (14 g, 54.1 mol), lithium hydroxide (1.5 g, 62.6 mol) and N,N-dimethylformamide (280 mL) were added into a 1000 mL reaction flask at room temperature, stirred at room temperature for 1 hour, and then cooled down to 0-5° C. Compound of Formula (+)-11 (27.5 g, 56.9 mol) was dissolved in N,N-dimethylformamide (30 mL) and then added dropwise into the reactor with the temperature controlled not to excess 5° C., the dripping process was completed within 4-5 hours. Then stirred to continue the reaction at 0-5° C. and the reaction was monitored by HPLC. After the reaction was completed, diethylamine (10 mL) was added to the reactor and stirred at 0-5° C. The reaction was monitored by HPLC. At the end of the reaction, water (250 mL) and ethyl acetate (300 mL) were added into the reactor, and the solution was separated by stirring. The aqueous layer was extracted with Ethyl acetate (200 mL×3). After extraction, the organic layers were combined and concentrated at 50° C. The concentrated residue was added with 85% lactic acid solution (15 g), stirred at room temperature for 1 hour, and then methyl tert-butyl ether (100 mL×2) was added for extraction. The aqueous layer was added with potassium carbonate to adjust to pH 8-9, then added with ethyl acetate (150 mL×3) for extraction. The organic layers were combined and concentrated at 45-50° C. under reduced pressure to obtain a crude product, which then was added with ethyl acetate (80 mL) and stirred at room temperature for 0.5 h. After filtration, the filter cake was dried in vacuum to obtain compound of Formula (+)-13 (16.8 g, 3-step yield 71%), which was a white solid.
[α]D=+81.21° (c=0.52, CHCl3)
1H NMR (400 MHz, Chloroform-d) δ 8.32 (s, 1H), 8.26 (s, 1H), 7.98 (s, 1H), 4.34 (d, J=13.9 Hz, 1H), 4.16 (d, J=13.9 Hz, 1H), 3.88 (t, J=3.1 Hz, 1H), 3.29 (t, J=3.4 Hz, 1H), 2.97 (d, J=10.9 Hz, 1H), 2.52 (t, J=11.8 Hz, 1H), 2.10 (d, J=15.1 Hz, 1H), 2.03 (dd, J=13.1, 3.7 Hz, 2H), 1.83 (d, J=13.2 Hz, 1H), 1.81-1.72 (m, 1H), 1.54 (ddt, J=15.0, 12.0, 3.4 Hz, 2H).
13C NMR (126 MHz, Chloroform-d) δ 160.1, 149.5, 147.2, 133.4, 132.7, 129.4, 127.9, 122.1, 105.3, 78.0, 55.8, 50.3, 44.67, 43.7, 26.9, 20.2.
HRMS (m/z): calc. for C16H18BrClN3O3 [M+H]+=414.0220/416.0200; found, 414.0216/416.0197
Step (6): Compound of Formula (+)-13 (15 g, 36.17 mmol) and anhydrous ethanol (150 mL) were added into a 500 mL reaction flask at room temperature, stirred and heated to reflux reaction which was monitored by HPLC. After the reaction, the reaction liquid was cooled to 55-60° C. After filtration under reduced pressure, the filter cake was leached with ethanol and vacuum dried to obtain (+)-halofuginone, which was a white solid (12.1 g, yield 80.6%, HPLC purity 98.5%, EE=99.6%).
[60 ]D=+18.52° (c=0.53, DMSO)
1H NMR (400 MHz, DMSO-d6) δ 8.23 (s, 1H), 8.22 (s, 1H), 8.15 (s, 1H), 4.99 (d, J=2.8 Hz, 2H), 4.79 (d, J=5.8 Hz, 1H), 2.98 (dt, J=15.3, 4.7 Hz, 2H), 2.78 (d, J=12.3 Hz, 1H), 2.64 (td, J=8.9, 3.8 Hz, 1H), 2.44 (dd, J=15.5, 8.7 Hz, 1H), 2.36 (td, J =12.1, 2.7 Hz, 1H), 1.95-1.83 (m, 1H), 1.56 (dt, J=13.3, 3.2 Hz, 1H), 1.34 (qt, J=12.4, 3.7 Hz, 1H), 1.28-1.13 (m, 1H).
13C NMR (126 MHz, DMSO-d6) δ 200.7, 158.6, 149.5, 147.2, 132.4, 131.8, 128.4, 126.8, 121.7, 66.7, 56.2, 54.4, 43.0, 30.5, 20.1.
HRMS (m/z): calc. for C16H18BrClN3O3 [M+H]+=414.0220/416.0200; found, 414.0214/416.0195
The above-described various technical features in the embodiments can be combined in various ways. The above-described embodiments do not describe all the possible combinations of the technical features to provide a concise description. However, those combinations which are not described should be within the scope of the description as long as no contradiction occurs in the combinations of these technical features.
The above-described embodiments represent only several embodiments of the present invention, which are described in specific detail but should not be construed as limitations on the scope of the claims. It should be noted that modifications and improvements can be made for those skilled in the art without departing from the spirit of the invention, all of which fall within the scope of the present invention. Accordingly, the scope of the present invention should be subject to the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201811626095.2 | Dec 2018 | CN | national |
| 201910090473.8 | Jan 2019 | CN | national |
This application is a continuation of international PCT application serial no. PCT/CN2019/106485, filed on Sep. 18, 2019, which claims the priority benefit of China application no. 201811626095.2 filed on Dec. 28, 2018, and China application no. 201910090473.8, filed on Jan. 30, 2019. The entirety of each of the above mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2019/106485 | Sep 2019 | US |
| Child | 17359661 | US |
