3,(2,4,5-Trisubstituted benzoyl)-propionic acid and the salts thereof

Abstract

A compound of the formula ##STR1## wherein R.sub.1 is a C.sub.1-4 alkoxy, R.sub.2 is C.sub.1-4 alkyl and R.sub.3 is C.sub.1-4 alkylthio or pharmaceutically acceptable salts thereof. The compounds of the present invention exhibit excellent choleretic activity.

Description

This invention relates to a novel 3-(trisubstituted benzoyl)-propionic acid and the production thereof.

Heretofore, there has been no report that benzoyl propionic acid derivatives have spasmolytic or relaxing action on a gall bladder, the common biliary duct, especially Oddi's sphincter.

The present inventors have found that a compound represented by the following formula (I) has a strong spasmolytic or relaxing action on a gall bladder, the common biliary duct, especially Oddi's sphincter as well as strong choleretic activity and low toxicity: ##STR2## wherein R.sub.1 is an alkyl group of 1 to 4 carbons, an alkoxy group of 1 to 4 carbons or hydroxyl, and R.sub.2 and R.sub.3 are, the same as or different from each other, an alkyl group of 1 to 4 carbons, an alkoxy group of 1 to 4 carbons, hydroxyl, halogen or an alkylthio group of 1 to 4 carbons or they are, connecting with each other, an alkylenedioxy group of 1 to 3 carbons, with the proviso that when R.sub.1 is the alkoxy group, at least one of R.sub.2 and R.sub.3 is the alkoxy group or the alkylthio group or R.sub.2 and R.sub.3 are, connecting with each other, the alkylenedioxy, when R.sub.1 is the alkyl group or hydroxyl, R.sub.2 and R.sub.3 are, the same or different, the alkoxy group, the alkylthio group or, connecting with each other, the alkylenedioxy, when R.sub.2 and R.sub.3 are methoxy, R.sub.1 is an alkyl group of 2 or 3 carbons, an alkoxy group of 2 to 4 carbons or hydroxyl and when R.sub.2 is methyl and R.sub.3 is methoxy, R.sub.1 is an alkoxy group of 2 to 4 carbons.

Referring to the formula (I), the alkyl group of R.sub.1, R.sub.2 or R.sub.3 may be exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, sec.butyl and tert. butyl. The alkoxy group of R.sub.1, R.sub.2 or R.sub.3 may be exemplified by methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec.butoxy and tert. butoxy. The halogen atom of R.sub.2 or R.sub.3 may be exemplified by chlorine, bromine, iodine and fluorine. The alkylthio group of R.sub.2 or R.sub.3 may be exemplified by methylthio, ethylthio, n-propylthio, isopropylthio, n-butylthio, sec. butylthio and tert. butylthio and the alkylenedioxy group formed by connection of R.sub.2 and R.sub.3 may be exemplified by methylenedioxy, ethylenedioxy, propylenedioxy.

The compound of the formula (I) can be produced by, for example,

1. reacting a compound of the formula (II) ##STR3## wherein R.sub.1, R.sub.2 and R.sub.3 have the same meaning as defined above with a reactive derivative of succinic acid such as succinic anhydride, succinic acid half ester half halide, succinic acid half ester half nitrile or succinic acid half ester and hydrolysing the resultant compound, if necessary.

2. subjecting a coupound of the formula (III) ##STR4## wherein R.sub.1, R.sub.2 and R.sub.3 have the same meaning as defined above to hydrogenation, and

3. treating a compound of the formula (IV) ##STR5## wherein R.sub.1, R.sub.2 and R.sub.3 have the same meaning as defined above and R.sub.5 and R.sub.6 are the same or different from each other, esterified carboxyl group or cyano or one of R.sub.5 and R.sub.6 is hydrogen and the other is cyano with an acid or an alkali.

4. and the compound (I) wherein R.sub.1 is hydroxyl, namely the compound of the formula ##STR6## wherein R.sub.8 and R.sub.9 are, the same or different from each other, an alkoxy group of 1 to 4 carbons or an alkylthio group of 1 to 4 carbons, or connecting with each other an alkylene-dioxy group of 1 to 3 carbons can be produced by, for example, subjecting a compound of the formula Vi ##STR7## wherein R.sub.7 is an alkoxy group and R.sub.8 and R.sub.9 have the same meaning as above to ether cleavage reaction.

The esterified carboxyl group of R.sub.5 and R.sub.6 may be exemplified by alkoxycarbonyl (e.g. methoxycarbonyl, ethoxycarbonyl, etc.), aralkoxycarbonyl (e.g. benzyloxycarbonyl, phenethyloxycarbonyl, etc.) and aryloxycarbonyl (phenoxycarbonyl, tolyloxycarbonyl, etc.).

An alkoxy group of R.sub.7, R.sub.8 and R.sub.9, an alkylthio group and an alkylenedioxy group of R.sub.8 and R.sub.9 may be the same as those of R.sub.1, R.sub.2 and R.sub.3.

The manner for the production of the compound (I) by the reaction between the compound (II) and the reactive derivative of succinic acid varies with the kind of reactive derivatives of succinic acid. Typical production methods are as follows:

1-A. The reaction between the compound (II) and succinic anhydride gives directly the compound (I).

1-B. The reaction between the compound (II) and succinic acid half ester half halide such as .beta.-methoxycarbopropionyl chloride and .beta.-ethoxycarbopropionyl chloride or succinic acid half ester half nitrile such as methyl .beta.-cyanopropionate and ethyl .beta.-cyanopropionate gives the ester corresponding to the compound (I) and the hydrolysis of the ester gives the compound (I).

1-C. The reaction between the compound (II) and a succinic acid half ester such as monomethyl succinate and monoethyl succinate in the presence of polyphosphoric acid or polyphosphoric acid ester gives the ester corresponding to the compound [I], and the hydrolysis of the ester gives the compound [I].

The reaction of the above (1-A) or (1-B) is advantageously carried out in a suitable inert solvent such as an aromatic hydrocarbon or its derivative (e.g. benzene, toluene, xylene, nitrobenzene), halogeno aliphatic hydrocarbon (e.g. methylene chloride, chloroform, carbon tetrachloride, ethylene dichloride, ethylene tetrachloride), ether (e.g. ethyl ether, propyl ether, isopropyl ether, ethyleneglycol dimethylether, ethyleneglycol diethylether) and carbon disulfide, or a mixture of two or more of them. It is desirable to carry out the reaction under anhydrous conditions and in the presence of a metal chloride such as anhydrous aluminum chloride, stannic chloride, zinc chloride and titanium tetrachloride or a mixture of two or more of them. The reaction temperature is, generally, -70.degree. to 200.degree. C. and preferably -10.degree. to 100.degree. C. The introduction of dry hydrogen chloride to the reaction system can serve to accelerate the desired reaction.

The reaction of the above (1-C) may conveniently be carried out in the absence of a solvent. In this reaction, any polyphosphoric acid or polyphosphoric acid ester can be employed. Generally, it may be used in an amount of 2 to 20 times, preferably 5 to 10 times as much as the compound (II). The reaction temperature is, in general, 0.degree. to 250.degree. C., preferably 30.degree. to 100.degree. C. The other conditions may be the same as those of the reaction (1-A) or (1-B).

The reactions of (1-B) and (1-C) give the ester corresponding to the compound (I). The ester, in the reaction mixture or isolated from the reaction mixture, is subjected to hydrolysis. The hydrolysis is carried out under acidic or alkaline conditions. In case of alkaline conditions, the hydrolysis may conveniently be carried out in the presence of water or a mixture of water and a lower alcohol such as methanol and ethanol in the presence of an alkaline substance such as sodium hydroxide or potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium carbonate at a temperature ranging from about -10.degree. to 150.degree. C. In case of acidic conditions, the hydrolysis may conveniently be carried out in water or a mixture of water and a lower alcohol such as methanol and ethanol, an ether such as tetrahydrofuran and dioxane or an organic acid such as formic acid and acetic acid in the presence of a mineral acid such as hydrochloric acid, sulfuric acid and phosphoric acid at a temperature ranging from about -10.degree. to 150.degree. C. In the reaction of (1-C). after the condensation reaction between the compound (II) and the succinic acid half ester is completed, polyphosphoric acid or polyphosphoric acid half ester is completed, polyphosphoric acid or polyphosphoric acid ester in the reaction mixture is hydrolized by the addition of water. The hydrolysis of the ester of the compound (I) is easily carried out by the addition of an aqueous organic solvent and heating the reaction mixture.

Hydrogenation of the reaction (2) mentioned above may be carried out in a conventional manner such as catalytic reduction, a reduction using an acid with a metal such as zinc, iron or tin, or an amalgam such as sodium amalgam. Catalytic reduction is generally carried out in a suitable solvent such as a lower alcohol (e.g. methanol, ethanol), an ether (e.g. dioxane, tetrahydrofuran, isopropylether), acetic acid, ethyl acetate or water, or a mixture of one or more of them in the presence of a catalyst such as palladium, platinum, rhodium, and nickel.

The compound (III) is a novel compound and it may be produced by reacting the compound (II) with a reactive derivative of maleic acid, i.e., maleic anhydride in a manner similar to that of (1-A), (1-B) or (1-C).

Treatment of the compound (IV) with an acid or an alkali can be carried out in conditions similar to those of hydrolysis of the ester in the reaction (1-B) or (1-C).

Ether cleavage of the compound (VI) is carried out in the presence of an inorganic acid e.g. hydroiodic acid, hydrobromic acid, hydrochloric acid, a mixture of potassium iodide and polyphosphoric acid, an organic acid such as formic acid, acetic acid, trifluoroacetic acid or a mixture of the organic acid and sodium iodide or potassium iodide. In addition to the acid, a suitable solvent such as water, a lower alcohol, a phenol, an organic acid or an ether such as dioxane and tetrahydrofuran may be employed. The reaction temperature ranges, in general, from 0.degree. C. to 200.degree. C., preferably from 70.degree. to 160.degree. C.

In order to isolate the desired compound (I) from among any of the reaction mixtures described above, any conventional manner may be employed. For example, steam distillation, extraction with a solvent or an alkaline solution, distillation or chromatography may be advantageously employed.

The compound (I) may be obtained in the form of a pharmaceutically acceptable salt, such as metal salt with e.g. sodium, calcium, magnesium, lithium, ammonium salt ar amine salt.

The compound (I) thus produced is novel and has a strong spasmolytic or relaxing action on the smooth muscles of a gall bladder, the common biliary duct, especially Oddi's sphincter as well as strong choleretic activity and low toxicity. Therefore it is very useful as a therapeutic agent for cholerystopathy, especially biliary dyskinesia and cholelithiasis, or cholagogus.

The compound (I) can be administered orally in the form of a tablet, granules, powder, or by way of injection.

The typical effective daily dose of the compound (I) is usually about 20 to 1000 mg, preferably, 50 to 300mg. when administered intravenously to an adult human. Of course, an increased or reduced dose may also be effective depending upon the symptoms.

In the following examples, the relationship between parts by weight and parts by volume corresponds to the relationship between gram and milliliter.

EXAMPLE 1

To a mixture of 7.5 parts by weight of 1,2,4,-triethoxybenzene, 40 parts by volume of tetrachloroethane and 7.5 parts by weight of succinic anhydride is added 23 parts by weight of anhydrous aluminum chloride and the mixture is stirred for 1 hour at 25.degree. C. and for another 2 hours at 60.degree. C. After addition of 50 parts by weight of ice and 50 parts by volume of concentrated hydrochloric acid, the reaction mixture is subjected to steam distillation. After cooling, crystals separated from the remaining liquid are collected by filtration and recrystallized from aqueous ethanol, whereby 2.5 parts by weight of 3-(2',4',5'-triethoxybenzoyl)-propionic acid is obtained as colorless needles. m.p. 150.degree.-151.degree. C.

EXAMPLES 2 to 4

According to a manner similar to that of Example 1, the following compounds are obtained.

______________________________________Example No. Compound mp. (.degree. C.)______________________________________2 3-(2'-ethoxy-4',5'-dimethoxy- 156-158 benzoyl)-propionic acid3 3-(2'-n-butoxy-4',5'-dimethoxy- 156-157 benzoyl)-propionic acid4 3-(2',4',5'-tri-n-butoxybenzoyl)- 117-118 propionic acid______________________________________

EXAMPLE 5

To the mixture of 9.0 parts by weight of 3,4-diethoxytoluene, 6.0 parts by weigth of succinic anhydride and 100 parts by volume of carbon tetrachloride is added 27 parts by weight of anhydrous aluminum chloride. The mixture is stirred for 1 hour at 25.degree. C. and mildly refluxed for 2 hours. After cooling, 70 parts by weight of ice and 70 parts by volume of concentrated hydrochloric acid are added to the mixture. Methylenedichloride is further added to the mixture and the whole mixture is shaken. The organic solvent layer is separated and extracted with a 2N-aqueous solution of sodium carbonate. The aqueous solution is adjusted with diluted hydrochloric acid to pH 2.5, whereby 3-(2'-methyl-4',5'-diethoxybenzoyl)-propionic acid is obtained as crystals. Recrystallization of the crystals gives 10.0 parts by weight of colorless plates melting at 116.degree.-117.degree. C.

EXAMPLES 6-14

According to a similar manner to that of Example 5, the following compounds are produced.

______________________________________ExampleNo. Compound mp. (.degree. C.)______________________________________ 6 3-(2',4'-dimethoxy-5'-chlorobenzoyl)- 185-187 propionic acid 7 3-(2'-n-propyl-4',5'-dimethoxybenzoyl)- 95-96 propionic acid 8 3-(2'-n-propyl-4'-methoxy-5'-ethoxy- 93 benzoyl)-propionic acid 9 3-(2'-n-propyl-4'-methoxy-5'-n-propoxy- 70 benzoyl)-propionic acid10 3-(2'-n-propyl-4'-methoxy-5'-n-butoxy- 85-86 benzoyl)-propionic acid11 3-(2',4'-diethoxy-5'-chlorobenzoyl)- 172-173 propionic acid12 3-(2'-methoxy-4'-t.-butyl-5'-ethoxy- 135-137 benzoyl)-propionic acid13 3-(2',4'-diethoxy-5'-ethylbenzoyl)- 153-155 propionic acid14 3-(2'-methoxy-4'-chloro-5'-methoxy- 186-188 benzoyl)-propionic acid______________________________________

EXAMPLE 15

To the mixture of 13.6 parts by weight of 1-ethoxy-3,4-dimethoxybenzene, 12 parts by weight of .beta.-ethoxycarbopropionyl chloride and 65 parts by volume of benzene is added 18 parts by weight of anhydrous stannic chloride over 25 minutes and the mixture is stirred at 25.degree. C. for 1 hour. The mixture is cooled at 5.degree. C. and 130 parts by volume of 20% hydrochloric acid is added thereto on stirring. To the mixture is added 250 parts by volume of methylene chloride and shaken. The methylene chloride layer is separated and extracted with a 5% aqueous solution of sodium bicarbonate twice and then washed with water twice. After drying with anhydrous calcium chloride, the solvent is distilled off.

To the residue are added 120 parts by volume of methanol and 95 parts by volume of 1N-methanolic potassium hydroxide. The mixture is stirred at 60.degree. C. for 1 hour. After removal of methanol by distillation under reduced pressure, to the residue are added 150 parts by volume of water and 100 parts by volume of methylene chloride, and the mixture is shaken. The aqueous layer is separated and adjusted to pH 2.5 with concentrated hydrochloric acid, whereby 14 parts by weight of 3-(2'-ethoxy-4',5'-dimethoxybenzoyl)-propionic acid as pale yellow crystals. mp.156.degree.-158.degree. C.

EXAMPLES 16-23

After a manner similar to that of Example 15, the following compounds are obtained.

______________________________________ExampleNo. Compound mp. (.degree. C.______________________________________16 3-(2',4',5'-triethoxybenzoyl)- 150-151 propionic acid17 3-(2'-n-butoxy-4',5'-dimethoxy- 156-157 benzoyl)-propionic acid18 3-(2'-methoxy-4',5'-methylenedioxy- 140-141 benzoyl)-propionic acid19 3-(2'-n-propyl-4',5'-methylenedioxy- 138-139 benzoyl)-propionic acid20 3-(2'-n-propyl-4'-methoxy-5'-n-butoxy- 85-86 benzoyl)-propionic acid21 3-(2'-ethoxy-4'-methyl-5'-methylthio- 117-118 benzoyl)-propionic acid22 3-(2'-methoxy-4'-chloro-5'-methoxy- 186-188 benzoyl)-propionic acid23 3-(2'-methoxy-4'-t.-butylbenzoyl-5'- 135-137 ethoxy)-propionic acid______________________________________

EXAMPLE 24

In 30 parts by volume of dried ethylether are dissolved 3.0 parts by weight of 1,2,4-triethoxybenzene and 3.0 parts by weight of methyl .beta.-cyanopropionate. To the solution are added 2.0 parts by weight of anhydrous zinc chloride and 2.0 parts by weight of anhydrous aluminum chloride. Hydrogen chloride gas is passed through the mixture over 30 minutes. The mixture is left standing at 15.degree. C. for 15 hours and 100 parts by volume of ethylether is added thereto. After removal of the upper layer, the residue is mixed with 100 parts by volume of 20% hydrochloric acid and refluxed for 30 minutes whereby pale yellow crystals are separated. After cooling, the crystals are collected by filtration (yield: 4.3 parts).

The crystals thus-obtained are mixed with 30 parts by volume of methanol and 50 parts by volume of 1N-methanolic potassium hydroxide and heated for 40 minutes. After removal of the solvent, the remaining liquid is dissolved in 70 parts by volume of water and neutralized with concentrated hydrochloric acid, whereby 3.0 parts by weight of 3-(2',4',5'-triethoxybenzoyl)-propionic acid is obtained as crystals melting at 150.degree.-151.degree. C.

EXAMPLE 25

According to a similar manner to that of Example 24, 3-(2',4',5'-tri-n-butoxybenzoyl)-propionic acid is obtained as colorless crystals melting at 117.degree.-118.degree. C.

EXAMPLE 26

A mixture of 12 parts by weight of 3,4-diethoxytoluene, 10 parts by weight of succinic acid monoethyl ester and 100 parts by weight of polyphosphoric acid is heated at 50.degree. C. for 1 hour. To the mixture is added 200 parts by volume of icewater and the mixture is extracted with ethylether. By distilling off the solvent 15 parts by weight of ethyl 3-(2'-methyl-4',5'-diethoxybenzoyl)-propionate is obtained as crystals melting at 81.degree.-82.degree. C.

The crystals are added to a mixture of 70 parts by volume of methanol and 70 parts by volume of 1N-methanolic potassium hydroxide and heated at 50.degree. C. for 1 hour. After removal of methanol, the remaining liquid is dissolved in water and neutralized with concentrated hydrochloric acid, whereby 3-(2'-methyl-4',5'-diethoxybenzoyl)-propionic acid is obtained as crystals. Recrystallization from aqueous methanol gives 12 parts by weight of colorless platelets melting at 116.degree.-117.degree. C.

EXAMPLES 27-32

According to a similar manner to that of Example 26, the following compounds are obtained.

______________________________________Example No. Compound mp. (.degree. C.)______________________________________27 3-(2'-methoxy-4'-t.-butyl-5'- 135-137 ethoxybenzoyl)-propionic acid28 3-(2'-n-propyl-4'-methoxy-5'-n- 70 propoxybenzoyl)-propionic acid29 3-(2',4',5'-tri-n-butoxybenzoyl)- 117-118 propionic acid30 3-(2'-methoxy-4',5'-methylenedioxy- 140-141 benzoyl)-propionic acid31 3-(2'-n-butoxy-4',5'-dimethoxybenzoyl)- 156-157 propionic acid32 3-(2',5'-diethoxy-4'-methylbenzoyl)- 128-129 propionic acid______________________________________

EXAMPLE 33

To a 50% (weight/volume) chloroform solution of polyphosphoric acid ester are added 5 parts by weight of 1,2,4-triethoxybenzene and 3 parts by weight of succinic acid half methyl ester. The mixture is heated at 50.degree. C. for 1 hour and mixed with 50 parts by volume of ice-water and 30 parts by volume of chloroform and then stirred for 40 minutes at 26.degree. C.

The chloroform layer is separated and washed with water and dried. The solvent is distilled off. To the residue is added 30 parts by volume of methanol and 30 parts by volume of 1N-methanolic potassium hydroxide. The mixture is stirred for 40 minutes at 50.degree. C. and the solvent is distilled off. The residue is dissolved in 100 parts by volume of water and washed with 30 parts by volume of diethylether. The pH of the mixture is adjusted to 2.5 with concentrated hydrochloric acid whereby 3-(2',4',5'-triethoxybenzoyl)-propionic acid is obtained as crsytals. Recrystallization of the crystals from aqueous acetone gives 4.1 parts by weight of colorless plates melting at 150.degree.-151.degree. C.

EXAMPLE 34

To a mixture of 2.1 parts by weight of 1,2,4-triethoxybenzene, 1.2 parts by weight of maleic anhydride and 30 parts by volume of carbon tetrachloride is added 5.2 parts by weight of anhydrous aluminum chloride. The mixture is stirred for 1 hour and heated at 50.degree. C. for another 1 hour. After cooling, concentrated hydrochloric acid and ice are added to the mixture. The mixture is extracted with methylenechloride and the methylenechloride layer is washed with water and dried over anhydrous sodium sulfate. Upon removing the solvent by distillation, 3-(2',4',5'-triethoxybenzoyl)-trans-acrylic acid is obtained as crystals. Recrystallization from a mixture of ethanol and benzene gives yellow needles melting at 192.degree.-194.degree. C.

A mixture of 1.0 part by weight of 3-(2',4',5'-triethoxybenzoyl)-trans-acrylic acid, 50 parts by volume of methanol and 0.2 part by weight of 5% palladium-charcoal is subjected to catalytic reduction at 25.degree. C. under atmospheric pressure for 1 hour. After removal of the catalyst by filtration, the filtrate is evaporated and the residue is recrystallized from aqueous ethanol to give 0.85 part by weight of 3-(2',4',5'-triethoxybenzoyl)-propionic acid as pale yellow needles melting at 150.degree.-151.degree. C.

EXAMPLES 35-38

According to a similar manner to that of Example 34, the following starting 3-(trisubstituted benzoyl)-acrylic acids and the objective 3-(trisubstituted benzoyl)-propionic acids are obtained.

______________________________________Ex. Starting Compound Cata- Objective compoundNo. Compound mp(.degree. C.) lyst Compound mp(.degree. C.)______________________________________ 3-(2'-methyl- 3-(2'-methyl-35 4',5'- 126 - Pd-C 4',5'- 116 - diethoxy- 127.5 diethoxy- 117 benzoyl)- benzoyl)- trans-acrylic propionic acid acid 3-(2',4'- 3-(2',4'-36 diethoxy-5'- 198 Na- diethoxy-5'- 172 - chloro- ama- chloro- 173 benzoyl)- lgam benzoyl)- trans-acrylic propionic acid acid 3-(2'-n- 3-(2'-n-37 propyl-4'- 91 - Pd-C propyl-4'- 85 - methoxy-5'-n- 93 methoxy-5'-n- 86 butoxy- butoxy- benzoyl)- benzoyl)- trans-acrylic propionic acid acid 3-(2'-n- 3-(2'-n-38 propyl-4'- 103 - Pd-C propyl-4'- 85 - methoxy-5'-n- 106 methoxy-5'-n- 86 butoxy- butoxy- benzoyl)-cis- benzoyl)- acrylic acid propionic acid______________________________________

EXAMPLE 39

To a mixture of 0.56 part by weight of diethyl malonate, 0.2 part by weight of 50% sodium hydride and 8.0 parts by volume of dried tetrahydrofuran is added 1.0 part by weight of 2',4',5'-triethoxyphenacyl chloride little by little at 25.degree. C., and is stirred for 10 hours. To the mixture are added 8 parts by volume of ethyl acetate and 50 parts by weight of ice water and shaken. The ethyl acetate layer is separated and washed with water and then dried and evaporated. The residue is recrystallized from methanol to give ethyl 3-(2', 4',5'-triethoxybenzoyl)-2-ethoxycarbopropionate as pale yellow plates melting at 97.degree.-98.degree. C.

A mixture of 1.5 part by weight of ethyl 3-(2',4',5'-triethoxybenzoyl)-2-ethoxycarbopropionate, 30 parts by volume of dioxane and 30 parts by volume of 30% sulfuric acid is heated at 120.degree. C. for 2 hours. The mixture is diluted with water and extracted with chloroform. The chloroform layer is separated and washed with water and dried. The solvent is distilled off, whereby 1.1 part by weight of 3-(2',4',5'-triethoxybenzoyl)-propionic acid is obtained. Recrystallization from aqueous methanol gives pale yellow needles melting at 150.degree.-151.degree. C.

EXAMPLE 40

According to a similar manner to that of Example 39, 2.0 parts by weight of 2',4',5'-triethoxyphenacylchloride is reacted with 0.9 part by weight of ethyl cyanacetate and 0.34 part by weight of 50% sodium hydride. The reaction mixture is subjected to chromatography with silica gel and eluted with benzene whereby 0.62 part by weight of 3-(2',4'-5'-triethoxybenzoyl)-2-ethoxycarbopropionitrile is obtained as crystalls. Recrystallization from methanol gives colorless plates melting at 109.degree.-110.degree. C.

One part by weight of 3-(2',4',5'-triethoxybenzoyl)-2-ethoxycarbopropionitrile is treated with 14 parts by volume of 4N-hydrochloric acid and 40 parts by volume of acetic acid at 100.degree.-110.degree. C. for 2 hours. The reaction mixture is treated according to the same manner as that of Example 39 whereby 0.65 part by weight of 3-(2',4',5'-triethoxybenzoyl)-propionic acid is obtained. mp.150.degree.-151.degree. C.

EXAMPLE 41

To a mixture of 5.0 parts by weight of 3-methoxy-4-n-butoxy-n-propylbenzene, 4.0 parts by weight of .beta.-chloropropionyl chloride and 20 parts by volume of dried benzene is added dropwise 9.0 parts by weight of stannic chloride dissolved in 5 parts by volume of carbon tetrachloride on cooling below 20.degree. C. After stirring for 2 hours, about 200 parts by volume of ice-water is added to the mixture and thereto is added 200 parts by volume of benzene and then the mixture is shaken. The benzene layer is separated and washed with water and dried. The solvent is distilled off and the residue is crystallized from petroleum ether whereby .OMEGA.-chloro-(2'-n-propyl-4'-methoxy-5'-n-butoxy)-propiophenone is obtained as colorless prisms. m.p. 42.degree.-43.degree. C.

To 30 parts by volume of dimethylsulfoxide is added 6.0 parts by weight of .OMEGA.-chloro-(2'-n-propyl-4'-methoxy-5'-n-butoxy)-propiophenone. To the mixture added 1.0 part by weight of sodium cyanide. The mixture is stirred for 2 hours at 80.degree. C. The reaction mixture is mixed with ice-water and extracted with benzene. The benzene layer is washed with water and dried. The solvent is distilled off and the residue is crystallized from aqueous ethanol to give 3-(2'-n-propyl-4'-methoxy-5'-n-butoxybenzoyl)-propionitrile is obtained as colorless needles melting at 76.degree. C.

A mixture of 1 part by weight of 3-(2'-n-propyl-4'-methoxy-5'-n-butoxybenzoyl)-propionitrile, 2 parts by volume of concentrated hydrochloric acid, 5 parts by volume of water and 5 parts by volume of acetic acid is stirred for 1.5 hour at 80.degree.-90.degree. C. The reaction mixture is diluted with water and extracted with methylenechloride and the extract is washed, dried and concentrated. The residue is mixed with n-hexane and cooled whereby 0.8 part by weight of 3-(2'-n-propyl-4'-methoxy-5'-n-butoxybenzoyl)-propionic acid is obtained as crystals. Recrystallization from a mixture of methylenechloride and n-hexane gives pale yellow crystals melting at 85.degree.-86.degree. C.

EXAMPLE 42

A mixture of 2 parts by weight of 3-(2',4',5'-triethoxybenzoyl)-propionic acid, 12 parts by weight of potassium iodide and 60 parts by volume of formic acid is refluxed for 3 hours and the solvent is distilled off. The residue is mixed with 50 parts by volume of water and stirred for a while and then insoluble substance is collected by filtration. The substance is washed with water and recrystallized from aqueous ethanol whereby 1.2 part by weight of 3-(2'-hydroxy-4',5'-diethoxybenzoyl)-propionic acid is obtained as colorless crystals melting at 142.degree.-144.degree. C.

EXAMPLES 43-45

According to a similar manner to that of Example 42, the following compounds are obtained.

______________________________________Example No. Compound mp. (.degree. C.______________________________________43 3-(2'-hydroxy-4',5'-dimethoxybenzoyl)- 162-163 propionic acid44 3-(2'-hydroxy-4',5'-methylenedioxy- 180-182 benzoyl)-propionic acid45 3-(2'-hydroxy-4',5'-n-butoxybenzoyl)- 127 propionic acid______________________________________

EXAMPLE 46

In 50 parts by volume of ethyl acetate are dissolved 9 parts by weight of 2-methyl-4,5-diethoxyacetophenone and 12 parts by weight of cupric bromide and the mixture is refluxed for 30 minutes. After removal of white inorganic substance by filtration, the filtrate is washed with water and dried over anhydrous sodium sulfate and the solvent is distilled off. The residue is recrystallized from petroleum ether to give 8.6 parts by weight of 2'-methyl-4',5'-diethoxyphenacylbromide as colorless crystals.

To a mixture of 15 parts by volume of dry tetrahydrofuran, 0.6 part by weight of diethyl malonate and 0.22 part by weight of sodium hydride is added 0.7 part by weight of 2'-methyl-4',5.dbd.-diethoxyphenacylbromide and the mixture is stirred for 12 hours. The reaction mixture is poured into water and acidified with diluted hydrochloric acid and extracted with ethyl acetate. The extract is washed with water, dried over anhydrous sodium sulfate, and the solvent is distilled off, whereby 0.68 part by weight of ethyl 3-(2'-methyl-4',5'-diethoxybenzoyl-2-ethoxycarbopropionate is obtained as oily substance. The substance shows the following IR absorption and NMR spectrum.

IR absorption: .delta..sub.max.sup.film cm.sup.-.sup.1 1750-1715 (ester), 1665 (ketone)

NMR spectrum (60MC, in CDC1.sub.3, .delta., p.p.m.):

1.1-1.6 (12H, triplet, --CH.sub.2 --CH.sub.3), 2.42 (3H, singlet, aromatic CH.sub.3), 3.35 (2H, doublet, --COCH.sub. 2 --), 3.6-4.4 (9H, quartet and multiplet, --CH.sub.2 --CH.sub.3 and --CH(COOC.sub.2 H.sub.5).sub.2), 6.62 (1H, singlet, C'.sub.3 --H), 7.28 (1H, singlet, C'.sub.6 --H)

According to a similar manner to that of Example 39, 3-(2'-methyl-4',5'-diethoxybenzoyl)-propionic acid is obtained from ethyl 3-(2'-methyl-4',5'-diethoxybenzoyl-2-ethoxycarbopropionate.

EXAMPLES 47-49

According to a similar manner to that of Example 41, the following starting 3-(trisubstituted benzoyl)-propionitriles and the objective 3-(trisubstituted benzoyl)-propionic acids are obtained.

__________________________________________________________________________Example Starting Compound Objective compoundNo. Compound mp (.degree. C.) Compound mp (.degree. C.)__________________________________________________________________________47 3-(2',4',5'-triethoxy- 117- 3-(2',4',5'-triethoxy- 150- benzoyl)-propionitrile 118 benzoyl)-propionic acid 15148 3-(2',4'-diethoxy-5'- 141- 3-(2',4'-diethoxy-5'- 172- chlorobenzoyl)-propio- 142 chlorobenzoyl)-propio- 173 nitrile nic acid49 3-(2'-ethoxy-4'-methyl- 99- 3-(2'-ethoxy-4'-methyl- 117- 5'-methylthiobenzoyl)- 100 5'-methylthiobenzoyl-propio- 118 propionitrile nic acid__________________________________________________________________________

Claims

1. A compound of the formula ##STR8## wherein R.sub.1 is an alkoxy group of 1 to 4 carbons, R.sub.2 is an alkyl group of 1 to 4 carbons and R.sub.3 is an alkylthio group of 1 to 4 carbons or pharmaceutically acceptable salts thereof.

2. A compound claimed in claim 1 which is 3-(2'-ethoxy-4'-methyl-5'-methylthiobenzoyl) propionic acid.