Patent Application
20130217920
This invention relates to methods, which provide access to [F-18]fluoropegylated (aryl/heteraryl vinyl)-phenyl methyl amine derivatives.
Alzheimer's Disease (AD) is a progressive neurodegenerative disorder marked by loss of memory, cognition, and behavioral stability. AD is defined pathologically by extracellular senile plaques comprised of fibrillar deposits of the beta-amyloid peptide (Aβ) and neurofibrillary tangles comprised of paired helical filaments of hyperphosphorylated tau. The 39-43 amino acids comprising Aβ peptides are derived from the larger amyloid precursor protein (APP). In the amyloidogenic pathway, Aβ peptides are cleaved from APP by the sequential proteolysis by beta- and gamma-secretases. Aβ peptides are released as soluble proteins and are detected at low level in the cerebrospinal fluid (CSF) in normal aging brain. During the progress of AD the Aβ peptides aggregate and form amyloid deposits in the parenchyma and vasculature of the brain, which can be detected post mortem as diffuse and senile plaques and vascular amyloid during histological examination (for a recent review see: Blennow et al. Lancet. 2006 Jul. 29; 368(9533):387-403). Alzheimers disease (AD) is becoming a great health and social economical problem all over the world. There are great efforts to develop techniques and methods for the early detection and effective treatment of the disease. Currently, diagnosis of AD in an academic memory-disorders clinic setting is approximately 85-90% accurate (Petrella J R et al. Radiology. 2003 226:315-36). It is based on the exclusion of a variety of diseases causing similar symptoms and the careful neurological and psychiatric examination, as well as neuropsychological testing.
Molecular imaging has the potential to detect disease progression or therapeutic effectiveness earlier than most conventional methods in the fields of neurology, oncology and cardiology. Among the several promising molecular imaging technologies, such as optical imaging, MRI, SPECT and PET, PET is of particular interest for drug development because of its high sensitivity and ability to provide quantitative and kinetic data.
For example positron emitting isotopes include e.g. carbon, iodine, nitrogen, and oxygen. These isotopes can replace their non-radioactive counterparts in target compounds to produce PET tracers that have similar biological properties. Among these isotopes F-18 is a preferred labeling isotope due to its half life of 110 min, which permits the preparation of diagnostic tracers and subsequent study of biochemical processes. In addition, its low β+ energy (634 keV) is also advantageous.
Post-mortem histological examination of the brain is still the only definite diagnosis of Alzheimer's disease. Thus, the in vivo detection of one pathological feature of the disease—the amyloid aggregate deposition in the brain—is thought to have a strong impact on the early detection of AD and differentiating it from other forms of dementia. Additionally, most disease modifying therapies which are in development are aiming at lowering of the amyloid load in the brain. Thus, imaging the amyloid load in the brain may provide an essential tool for patient stratification and treatment monitoring (for a recent review see: Nordberg. Eur J Nucl Med Mol Imaging. 2008 March; 35 Suppl 1:S46-50). In addition, amyloid deposits are also known to play a role in amyloidoses, in which amyloid proteins (e.g. tau) are abnormally deposited in different organs and/or tissues, causing disease. For a recent review see Chiti et al. Annu Rev Biochem. 2006; 75:333-66.
Since nucleophilc radiofluorination was performed using nano- and sub-nanomolar quantities of [F-18]fluoride is it well known, that only small amounts of labeling precursor are necessary for successful radiolabeling. Generally, few micromole of precursor provide a huge excess with respect to the radioisotope, resulting in pseudo-first-order reaction kinetics (P. W. Miller et al., Ang. Chem. Int. Ed. 47 (2008) 8998-9033).
Direct radiofluorinations of fluoropegylated bis-aryl/heteroaryl Aβ ligands L have been described in the literature.
a) Diphenylacetylenes B
Labelings of 1 mg (1.83-2.48 μmol) precursor A in DMSO using potassium carbonate/kryptofix complex afforded B in 20-30% radiochemical yield (decay corrected).
b) Indolinyl- and indolylphenylacetylenes D
Labelings of precursor C in DMSO using potassium carbonate/kryptofix complex afforded D in 11-16% radiochemical yield (decay corrected).
c) Flavone Derivatives F
Labelings of 0.2 mg (0.35-0.42 μmol) precursor E in DMSO using potassium carbonate/kryptofix complex afforded F in 5-13% radiochemical yield (decay corrected).
d) Phen-Naphthalene and Phen-quinoline Derivatives H
Labelings of 1 mg (2.11 μmol) precursor G in DMSO using potassium carbonate/kryptofix complex afforded H in 30% radiochemical yield (decay corrected).
e) Benzothiazole Derivatives J
Labelings of precursor I in DMSO using potassium carbonate/kryptofix complex afforded H in 11-35% radiochemical yield (decay corrected). The influence of amount of precursor was investigated (example n=2), and 1-3 mg (1.91-5.74 μmol) were found to be optimal for this kind of conversion. Also fluoropegylated (aryl/heteraryl vinyl)-phenyl methyl amines such as 4-[(E)-2-(4-{2-[2-(2-fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline and 4-[(E)-2-(6-{2-[2-(2-fluoroethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline have been labeled with F-18 fluoride before and are covered by patent applications WO2006066104, WO2007126733 and members of the corresponding patent families.
4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-methylaniline
a) W. Zhang et al., Nuclear Medicine and Biology 32 (2005) 799-809 mg (7.47 μmol) precursor 2a (2[2-(2-{4-[(E)-2-{4-[(tert-butoxycarbonyl) (methyl)amino]-phenyl}vinyl]phenoxy}ethoxy)ethoxy]ethyl methanesulfonate) in 0.2 mL DMSO were reacted with [F-18]fluoride/kryptofix/potassium carbonate complex. The intermediate was deprotected with HCl and neutralized with NaOH. The mixture was extracted with ethyl acetate. The solvent was dried and evaporated. The residue was dissolved in acetonitrile and purified by semi-preparative HPLC. 20% (decay corrected), 11% (not corrected for decay) 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline were obtained within 90 min.
Very recently, further syntheses have been described:
a) US20100113763
b) H. Wang et al., Nuclear Medicine and Biology 38 (2011) 121-127
a) S. R. Choi et al., The Journal of Nuclear Medicine 50 (2009) 1887-1894.
b) WO2010078370
c) Y. Liu et al., Nuclear Medicine and Biology 37 (2010) 917-925
A “GMP compliant” manufacturing process for 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline is disclosed in WO2010078370 and C.-H. Yao et al., Applied Radiation and Isotopes 68 (2010) 2293-2297. The radiolabeling of 1.63 μmol-2.45 mmol was performed in DMSO and to prevent the decomposition of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline, sodium ascorbate was added to the HPLC solvent (45% acetonitrile, 55% 20 mM ammoniumacetate containing 0.5% (w/v) sodium ascorbate) and the final Formulation (0.5% (w/v) sodium ascorbate). The process afforded up to 18.5 GBq (25.4±7.7%, decay corrected) 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline. The radiochemical purity was 95.3±2.2%.
So far, the maximum activity for a F-18 labeled fluoropegylated (aryl/heteraryl vinyl)-phenyl methyl amine derivative was reported to be 18.5 GBq (Yao et al.). However, even higher yields would be supportive for a widespread use and availability of the radiotracer. The Method of the present invention provides high yield of the F-18 tracer within a broad range of radioactivity in contrast to previous processes, wherein up-scaling is limited.
Despite the information from the literature, that amounts of less than 7.5 μmol and recently less than 12 μmol precursor are sufficient or even optimal for the preparation of F-18 labeled fluoropegylated (aryl/heteraryl vinyl)-phenyl methyl amine derivatives, a significant increase of radiochemical yield was found using more than 10 μmol or even more than 12 μmol precursor. The maximum activity for a F-18 labeled fluoropegylated (aryl/heteraryl vinyl)-phenyl methyl amine derivative was increased to 130 GBq and up-scaling was found to be almost linear (see
The method comprises the steps of:
In a first aspect the present invention is directed to a method for producing compound of Formula I
comprising the steps of:
X is selected from the group comprising
In one preferred embodiment, X=CH.
In another preferred embodiment, X=N.
R is selected from the group comprising
PG is an “amine-protecting group”.
In a preferred embodiment, PG is selected from the group comprising:
In a more preferred embodiment, R is H.
In another more preferred embodiment, R is Boc.
LG is a leaving group.
In a preferred embodiment, LG is selected from the group comprising:
In a preferred embodiment LG contains 0-3 fluorine atoms.
Halogen is chloro, bromo or iodo.
Preferably, Halogen is bromo or chloro.
In a preferred embodiment Sulfonyloxy is selected from the group consisting of Methanesulfonyloxy, p-Toluenesulfonyloxy, Trifluormethylsulfonyloxy, 4-Cyanophenylsulfonyloxy, 4-Bromophenylsulfonyloxy, 4-Nitrophenylsulfonyloxy, 2-Nitrophenylsulfonyloxy, 4-Isopropyl-phenylsulfonyloxy, 2,4,6-Triisopropylphenylsulfonyloxy, 2,4,6-Tri methylphenylsulfonyloxy, 4-tert-Butyl-phenylsulfonyloxy, 4-Adamantylphenylsulfonyloxy and 4-Methoxyphenylsulfonyloxy.
In a more preferred embodiment, Sulfonyloxy is selected from the group comprising:
In a even more preferred embodiment LG is Methanesulfonyloxy.
In another even more preferred embodiment LG is p-Toluenesulfonyloxy.
A preferred compound of Formula I is:
Another preferred compound of Formula I is:
A preferred compound of Formula II is:
Another preferred compound of Formula II is:
Another preferred compound of Formula II is:
Another preferred compound of Formula II is:
Another preferred compound of Formula II is:
Step 1 comprises a straight forward [F-18]fluoro labeling reaction from compounds of Formula II for obtaining compound of Formula I (if R=H) or compound of Formula III (if R=PG).
The radiolabeling method for comprises the step of reacting a compound of formula II with a F-18 fluorinating agent for obtaining a compound of formula III. In a preferred embodiment, the [F-18]fluoride derivative is 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo[8.8.8]-hexacosane K[F-18]F (crownether salt Kryptofix K[F-18]F), K[F-18]F, H[F-18]F, KH[F-18]F2, Cs[F-18]F, Na[F-18]F or tetraalkylammonium salt of [F-18]F (e.g.[F-18]tetrabutylammonium fluoride). More preferably, the fluorination agent is K[F-18]F, H[F-18]F, [F-18]tetrabutylammonium fluoride, Cs[F-18]F or is KH[F-18]F2, most preferably K[F-18], Cs[F-18]F or [F-18]tetrabutylammonium fluoride.
An even more preferred F-18 fluorinating agent is kryptofix/potassium[F-18]fluoride, preferably generated from [F-18]fluoride, kryptofix and potassium carbonate.
The radiofluorination reactions are carried out in acetonitrile, dimethylsulfoxide or dimethylformamide or a mixture thereof. But also other solvents can be used which are well known to someone skilled in the art. Water and/or alcohols can be involved in such a reaction as co-solvent. The radiofluorination reactions are conducted for less than 60 minutes. Preferred reaction times are less than 30 minutes. Further preferred reaction times are less than 15 min. This and other conditions for such radiofluorination are known to experts (Coenen, Fluorine-18 Labeling Methods: Features and Possibilities of Basic Reactions, (2006), in: Schubiger P. A., Friebe M., Lehmann L., (eds), PET-Chemistry—The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pp. 15-50).
In one embodiment, the Radiofluorination of compound of Formula II is carried out in a non-protic solvent or in a mixture of non-protic solvents.
In a preferred embodiment, the Radiofluorination of compound of Formula II is carried out in acetonitrile or in a mixture of acetonitrile and co-solvents, wherein the percentage of acetonitrile is at least 50%, more preferably at least 70%, even more preferably at least 90%.
In one embodiment, 7.5-75 μmol, preferably 10-50 μmol, more preferably 10-30 μmol and even more preferably 12-25 μmol and even more preferably 13-25 μmol of compound of Formula II are used in Step 1.
In another embodiment, more than 7.5 μmol, preferably more than 10 μmol, and more preferable more than 12 μmol and even more preferably more than 13 μmol of compound of Formula II are used in Step 1.
In another embodiment, more than 5 mg, preferably more than 6 mg and more preferably more than 7 mg of compound of Formula II are used in Step 1.
In another embodiment 7 mg of compound of Formula II are used in Step 1.
In another embodiment 8 mg of compound of Formula II are used in Step 1.
Optionally, if R=PG, Step 2 comprises the deprotection of compound of formula III to obtain compound of formula I. Reaction conditions are known or obvious to someone skilled in the art, which are chosen from but not limited to those described in the textbook Greene and Wuts, Protecting groups in Organic Synthesis, third edition, page 494-653, included herewith by reference. Preferred reaction conditions are addition of an acid and stirring at 0° C.-180° C.; addition of an base and heating at 0 ° C.-180 ° C.; or a combination thereof.
Preferably the step 1 and step 2 are performed in the same reaction vessel.
Step 3 comprises the purification and formulation of compound of Formula I.
Methods for purification of radiotracers are well known to person skilled in the art and include HPLC methods as well as solid-phase extraction methods.
In one embodiment, the crude product mixture is purified by HPLC and the collected product fraction is further passed through a solid-phase cartridge to remove the HPLC solvent (such as acetonitrile) and to provide the compound of Formula I in an injectable Formulation.
In an other embodiment, the crude product mixture is purified by HPLC, wherein, the HPLC solvent mixture (e.g. mixtures of ethanol and aqueous buffers) can be part of the injectable Formulation of compound of Formula I. The collected product fraction can be diluted or mixed with other parts of the Formulation.
In an other embodiment, the crude product mixture is purified by solid-phase cartridges.
In a preferred embodiment, the Method for manufacturing of compound of Formula I is carried out by use of a module (review: Krasikowa, Synthesis Modules and Automation in F-18 labeling (2006), in: Schubiger P. A., Friebe M., Lehmann L., (eds), PET-Chemistry—The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pp. 289-316) which allows an automated synthesis. More preferably, the Method is carried out by use of an one-pot module. Even more preferable, the Method is carried out on commonly known non-cassette type modules (e.g. Ecker&Ziegler Modular-Lab, GE Tracerlab FX, Raytest SynChrom) and cassette type modules (e.g. GE Tracerlab MX, GE Fastlab, IBA Synthera, Eckert&Ziegler Modular-Lab PharmTracer), optionally, further equipment such as HPLC or dispensing devices are attached to the said modules.
In a second aspect the present invention is directed to a fully automated and/or remote controlled Method for production of compound of Formula I wherein compounds of Formula I, II and III and Steps 1, 2 and 3 are described above. In a preferred embodiment this method is a fully automated process, compliant with GMP guidelines, that provides a Formulation of Formula I for the use of administration (injection) into human.
In a third aspect the present invention is directed to a Kit for the production of a pharmaceutical composition of compound of Formula I.
In one embodiment the Kit comprising a sealed vial containing a predetermined quantity of the compound of Formula II. Preferably, the Kit contains 7.5-75 μmol, preferably 10-50 μmol, more preferably 10-30 μmol and even more preferably 12-25 limol and even more preferably 13-25 μmol of compound of Formula II. In another embodiment the Kit contains more than 7.5 μmol, preferably more than 10 μmol and more preferably more than 12 μmol and even more preferably more than 13 μmol of compound of Formula II.
In another embodiment the Kit contains more than 5 mg, preferably more than 6 mg and more preferably more than 7 mg of compound of Formula II.
In another embodiment the Kit contains 7 mg of compound of Formula II.
In another embodiment the Kit contains 8 mg of compound of Formula II.
Optionally, the Kit contains further components for manufacturing of compound of Formula I, such as solid-phase extraction cartridges, reagent for fluorination (as described above), acetonitrile or acetonitrile and a co-solvent, reagent for cleavage of deprotection group, solvent or solvent mixtures for purification, solvents and excipient for formulation.
In one embodiment, the Kit contains a platform (e.g. cassette) for a “cassette-type module” (such as Tracerlab MX or IBA Synthera).
In the context of the present invention, preferred salts are pharmaceutically suitable salts of the compounds according to the invention. The invention also comprises salts which for their part are not suitable for pharmaceutical applications, but which can be used, for example, for isolating or purifying the compounds according to the invention.
Pharmaceutically suitable salts of the compounds according to the invention include acid addition salts of mineral acids, carboxylic acids and sulphonic acids, for example salts of hydrochloric acid, hydrobromic acid, sulphuric acid, phosphoric acid, methanesulphonic acid, ethanesulphonic acid, toluenesulphonic acid, benzenesulphonic acid, naphthalene disulphonic acid, acetic acid, trifluoroacetic acid, propionic acid, lactic acid, tartaric acid, malic acid, citric acid, fumaric acid, maleic acid and benzoic acid.
Pharmaceutically suitable salts of the compounds according to the invention also include salts of customary bases, such as, by way of example and by way of preference, alkali metal salts (for example sodium salts and potassium salts), alkaline earth metal salts (for example calcium salts and magnesium salts) and ammonium salts, derived from ammonia or organic amines having 1 to 16 carbon atoms, such as, by way of example and by way of preference, ethylamine, diethylamine, triethylamine, ethyldiisopropylamine, monoethanolamine, dietha-nolamine, triethanolamine, dicyclohexylamine, dimethylaminoethanol, procaine, diben-zylamine, N methylmorpholine, arginine, lysine, ethylenediamine and N methylpiperidine.
The term halogen or halo refers to CI, Br, F or I.
The term Sulfonyloxy refers to
—O—S(O)2—Q wherein Q is optionally substituted aryl or optionally substituted alkyl.
The term “alkyl” as employed herein by itself or as part of another group refers to a C1-C10 straight chain or branched alkyl group such as, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, heptyl, hexyl, decyl or adamantyl. Preferably, alkyl is C1-C6 straight chain or branched alkyl or C7-C10 straight chain or branched alkyl. Lower alkyl is a C1-C6 straight chain or branched alkyl.
The term “aryl” as employed herein by itself or as part of another group refers to monocyclic or bicyclic aromatic groups containing from 6 to 10 carbons in the ring portion, such as phenyl, naphthyl or tetrahydronaphthyl.
Whenever the term “substituted” is used, it is meant to indicate that one or more hydrogens on the atom indicated in the expression using “substituted” is/are replaced by one ore multiple moieties from the group comprising halogen, nitro, cyano, trifluoromethyl, alkyl and O-alkyl, provided that the regular valency of the respective atom is not exceeded, and that the substitution results in a chemically stable compound, i. e. a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture.
The term “amine-protecting group” as employed herein by itself or as part of another group is known or obvious to someone skilled in the art, which is chosen from but not limited to a class of protecting groups namely carbamates, amides, imides, N-alkyl amines, N-aryl amines, imines, enamines, boranes, N-P protecting groups, N-sulfenyl, N-sulfonyl and N-silyl, and which is chosen from but not limited to those described in the textbook Greene and Wuts, Protecting groups in Organic Synthesis, third edition, page 494-653, included herewith by reference. The amine-protecting group is preferably Carbobenzyloxy (Cbz), p-Methoxybenzyl carbonyl (Moz or MeOZ), tert-Butyloxycarbonyl (BOC), 9-Fluorenylmethyloxycarbonyl (FMOC), Benzyl (Bn), p-Methoxybenzyl (PMB), 3,4-Dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP) or the protected amino group is a 1,3-dioxo-1,3-dihydro-2H-isoindo1-2-yl(phthalimido) or an azido group.
The term “leaving group” as employed herein by itself or as part of another group is known or obvious to someone skilled in the art, and means that an atom or group of atoms is detachable from a chemical substance by a nucleophilic agent. Examples are given e.g. in Synthesis (1982), p. 85-125, table 2 (p. 86; (the last entry of this table 2 needs to be corrected: “n-C4F9S(O)2—O— nonaflat” instead of “n-C4H9S(O)2—O— nonaflat”), Carey and Sundberg, Organische Synthese, (1995), page 279-281, table 5.8; or Netscher, Recent Res. Dev. Org. Chem., 2003, 7, 71-83, scheme 1, 2, 10 and 15 and others). (Coenen, Fluorine-18 Labeling Methods: Features and Possibilities of Basic Reactions, (2006), in: Schubiger P. A., Friebe M., Lehmann L., (eds), PET-Chemistry—The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pp. 15-50, explicitly: scheme 4 pp. 25, scheme 5 pp 28, table 4 pp 30,
Unless otherwise specified, when referring to the compounds of formula the present invention per se as well as to any pharmaceutical composition thereof the present invention includes all of the hydrates, salts, and complexes.
The term “F-18” means fluorine isotope 18F. The term“F-19” means fluorine isotope 19F.
Radiochemical and chemical purities of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline and 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline were determined by analytical HPLC (column: Atlantis T3; 150×4.6 mm, 3 mm, Waters; solvent A: 5 mM K2HPO4 pH 2.2; solvent B: acetonitrile; flow: 2 mL/min, gradient: 0:00 min 40% B, 0:00-05:50 min 40-90% B, 05:50-05:60 min 90-40% B, 05:60-09:00 min 40% B).
The synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline have been performed on a Tracerlab FXN synthesizer (
The setup of the synthesizer and the results are summarized in Table 1. [F-18]Fluoride was trapped on a QMA cartridge (C1,
Significant increase of radiochemical yield for 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline was found after increasing the amount of precursor from 3.5 mg to 7.0 mg.
The synthesis of 4-[(E)-2-(4-{2-[2-(2-fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline has been performed on Eckert & Ziegler ModularLab synthesizer using tert-amyl alcohol as solvent for fluorination. The setup of the synthesizer and the results are summarized in Table 2.
[F-18]Fluoride was trapped on a QMA cartridge (C1). The activity was eluted with a kryptofix mixture (from “V1”) into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of acetonitrile (from “V2”). The solution of precursor (from “V3”) was added to the dried residue and the mixture was heated for 12 min at 120° C. The solvent of fluorination was removed under vacuum for 6 min at 120° C. After cooling to 40° C., HCl/acetonitrile mixture (from “V4”) was added and solution was heated for 8 min at 120° C.
The crude product mixture was diluted with 1.5 mL 2M NaOH and 0.3 mL ammonium formate (1 M) from “V5” and then directly transferred to the HPLC vial (“Mix-Vial”). To avoid the precipitation and the phase separation of the mixture due to the tert-amyl alcohol, the “Mix-Vial” contained previously 1 mL acetonitrile and 1 mL ethanol.
The mixture was purified by semi-preparative HPLC. The product fraction was collected into the “Flask” containing 16 mL water. The solution was passed through a tC18 environmental cartridge (C2). The cartridge was washed with 20% ethanol in water from “V6” and 4-[(E)-2-(4-{2-[2-(2-fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline was eluted with 1.5 mL ethanol from “V7” into the product vial containing 8.5 mL formulation basis (consisting of phosphate buffer, PEG400 and ascorbic acid).
A higher radiochemical yield of 38% (not corrected for decay) was obtained using 7.4 mg precursor compared to the process using 4.0 mg precursor that afforded 15% (not corrected for decay) 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline.
Significant increase of radiochemical yield for 4-[(E)-2-(4-{2-[2-(2-fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline was found after increasing the amount of precursor from 4.0 mg to 7.4 mg.
The synthesis have been performed on a Tracerlab FXN synthesizer. [F-18]Fluoride (6.85 GBq) was trapped on a QMA cartridge. The activity was eluted with potassium carbonate/kryptofix/acetonitrile/water mixture into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of acetonitrile. A solution of 8 mg 2c in 1.5 mL acetonitrile was added to the dried residue and the mixture was heated for 10 min at 120° C. After cooling to 60° C., the crude product was diluted with 4 mL HPLC eluent and transferred to a semi-preparative HPLC column (Synergy Hydro-RP, 250×10 mm, Phenomenex). A mixture of 60% ethanol and 40% ascorbate buffer (5g/I sodium ascorbate and 50mg/I ascorbic acid, pH 7.0) was flushed through the column with 3 mL/min. The product fraction at ≈12 min was directly collected for 100 sec and mixed with 15 mL Formulation basis (phosphate buffer, ascorbic acid, PEG400).
2.54 GBq (37% not corrected for decay) were obtained in 53 min overall synthesis time. Radiochemical purity (determined by HPLC, tR=3.78 min) was determined to be >99%.
Up-scaling of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline synthesis was performed on two different synthesizers (Eckert & Ziegler modular lab and GE tracerlab MX) by reacting 8 mg precursor 2a in acetonitrile at 100-120° C. for 10 min with potassium carbonate/kryptofix/[F-18]fluoride complex. The N-Boc protecting group was removed by heating with HCl (1.5M-2M). The crude product mixture obtained after deprotection was neutralized with a mixture of 2M NaOH and 0.1M ammonium formate, diluted with acetonitrile and ethanol and injected onto a semipreparative HPLC (column: e.g.: Gemini C18, 10×250 mm, 5 mm, Phenomenex or Synergi Hydro-RP, 250×10 mm, 10 μm 80 Å, Phenomenex or Synergi Hydro-RP, 250×10 mm, 4 μm 80 Å, Phenomenex; solvent: 60-70% ethanol, 40-30% ascorbate buffer≈5 mg/mL ascorbate; flow 3 mL/min or 4 mL/min or 6 mL/min). The product fractions were directly collected into a vials containing “Formulation basis” (comprising PEG400, phosphate buffer and ascorbic acid) to provide 10-24 mL of the final Formulation. The peak-cutting time was adjusted in the software to obtain a Formulation comprising 15% EtOH.
The results (83 experiments) are summarized in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10164948.1 | Jun 2010 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP11/58819 | 5/30/2011 | WO | 00 | 5/13/2013 |
