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  • C07C255/32—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms having cyano groups bound to acyclic carbon atoms of a carbon skeleton containing at least one six-membered aromatic ring
  • C07C255/34—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms having cyano groups bound to acyclic carbon atoms of a carbon skeleton containing at least one six-membered aromatic ring with cyano groups linked to the six-membered aromatic ring, or to the condensed ring system containing that ring, by unsaturated carbon chains
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  • C07C255/59—Carboxylic acid nitriles having cyano groups bound to carbon atoms of six-membered aromatic rings of a carbon skeleton containing cyano groups and singly-bound nitrogen atoms, not being further bound to other hetero atoms, bound to the carbon skeleton the carbon skeleton being further substituted by singly-bound oxygen atoms
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  • C07D307/77—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom ortho- or peri-condensed with carbocyclic rings or ring systems
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  • C12P13/00—Preparation of nitrogen-containing organic compounds
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  • C12P13/00—Preparation of nitrogen-containing organic compounds
  • C12P13/02—Amides, e.g. chloramphenicol or polyamides; Imides or polyimides; Urethanes, i.e. compounds comprising N-C=O structural element or polyurethanes
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  • C12P41/00—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture
  • C12P41/006—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture by reactions involving C-N bonds, e.g. nitriles, amides, hydantoins, carbamates, lactames, transamination reactions, or keto group formation from racemic mixtures
  • C12P41/007—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture by reactions involving C-N bonds, e.g. nitriles, amides, hydantoins, carbamates, lactames, transamination reactions, or keto group formation from racemic mixtures by reactions involving acyl derivatives of racemic amines
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  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/02—Preparation of oxygen-containing organic compounds containing a hydroxy group
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  • C07B2200/07—Optical isomers

Definitions

• the present invention relates to a novel method for the preparation of optically active intermediates useful for the preparation of escitalopram involving selective enzymatic acylation or deacylation.
• Citalopram is a well-known antidepressant drug that has now been on the market for some years.
• Citalopram was first disclosed in DE 2,657,013, corresponding to U.S. Pat. No. 4,136,193.
• This patent publication i.a. outlines a process for preparation of citalopram from the corresponding 5-bromo-derivative by reaction with cuprous cyanide in a suitable solvent and by alkylation of 5-bromo-phtalane.
• both processes use the racernic diol having the formula as starting material.
• the diol of formula (I) is reacted with an enantiomerically pure acid derivative, such as (+) or ( ⁇ )- ⁇ -methoxy- ⁇ -trifluoromethyl-phenylacetyl chloride to form a mixture of diastereomeric esters, which are separated by HPLC or fractional crystallization, whereupon the ester with the correct stereochemistry is enantioselectively converted into escitalopram.
• an enantiomerically pure acid derivative such as (+) or ( ⁇ )- ⁇ -methoxy- ⁇ -trifluoromethyl-phenylacetyl chloride
• the diol of formula (II) is separated into the enantiomers by stereoselective crystallization with an enantiomerically pure acid such as (+)-di-p-toluoyltartaric acid, whereupon the S-enantiomer of the diol of the formula (A) is enantioselectively converted to escitalopram.
• an enantiomerically pure acid such as (+)-di-p-toluoyltartaric acid
• Escitalopram has now been developed as an antidepressant. Hence, there is a desire for an improved method for preparation of escitalopram.
• the S-enantiomer of the diol of formula (I) above as well as acylated derivatives thereof may be prepared by selective enzymatic acylation of the primary hydroxyl group in the racemic diol to obtain S-diol or an acylated derivative thereof with high optical purity and further that the enantiomers obtained may be separated by a series of isolation and purification operations.
• the present invention relates to a novel process for the preparation of the S- or R-enantiomer of a diol having the formula wherein R is cyano or a group which may be converted to a cyano group, Z is a group —CH 2 —N(R′R′′) wherein R′ and R′′ are C 1-6 -alkyl, or R′ and R′′ are connected to each other to form a cyclic structure including the N-atom to which they are attached, or Z is a group which may be converted to a dimethylaminomethyl group, the dotted line represents a double or a single bond and Hal is halogen or a salt thereof, and/or the opposite enantiomer of an acylated diol having the formula wherein R, Z, the dotted line and Hal are as defined above, W is O or S, and R 3 is —Y—R 1 , wherein R 1 is C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10
• the invention also relates to methods for the separation of mixtures of an enantiomer of formula (IV) from the opposite enantiomer of formula (II) and to the R- and S-enantiomers of the compounds of formula (IV) above.
• the invention relates to a method for the preparation of escitalopram and racemic citalopram from the enantiomers of a compound of formula (II) obtained by the selective enzymatic acylation or deacylation according to the invention, or the enantiomers of the optically active acyl derivative of formula (IV) obtained by the selective enzymatic acylation or deacylation according to the invention.
• the terms “enantiomer”, “R-enantiomer”, “S-enantiomer”, “R-form”, “S-form”, “R-diol” and “S-diol” refer to the orientation og the groups around the carbon atom to which the 4-Hal-phenyl group is attached.
• the present invention thus relates in one embodiment to a selective enzymatic acylation as above and in another embodiment to selective enzymatic deacylation as above.
• Selective enzymatic acylation means that the enzymatic acylation is preferentially effective for conversion of one of the enantiomers of a compound of formula (II) preferentially leaving the other enantiomer of the compound of formula (II) unconverted in the reaction mixture.
• Selective enzymatic deacylation means that the enzymatic deacylation is preferentially effective for conversion of one of the enantiomers of a compound of formula (IV), preferentially leaving the other enantiomer of the compound of formula (IV) unconverted in the reaction mixture.
• the selective acylation according to the invention thus results in a mixture containing preferentially the compound of formula (II) in the S-form and the compound of formula (IV) in the R-form, or it may result in a mixture containing preferentially the compound of formula (II) in the R-form and the compound of formula (IV) in the S-form.
• the selective enzymatic deacylation may result in a mixture containing preferentially the compound of formula (IV) in the S-form and the compound of formula (II) in the R-form, or it may result in a mixture containing preferentially the compound of formula (IV) in the R-form and the compound of formula (II) in the S-form.
• composition mixture obtained after acylation or deacylation according to the invention depend on the specific hydrolase used and the conditions under which the reaction is carried out. Characteristic of the enzymatic acylation/deacylation according to the invention is that a considerably larger portion of one enantiomer is converted than of the other.
• the optical purity of the diol of formula (II) and/or the acylated compound of formula (IV) obtained by the optical resolution method of the present invention is usually at least 90% ee, preferably at least 95% ee, more preferably at least 97% ee and most preferably at least 98% ee. However, lower values for the optical purity are acceptable.
• the starting material for the enzymatic method of the invention is a racemic diol of formula (II) or a racemic acyl derivative of formula (IV)
• R is halogen or cyano, most preferred cyano.
• Hal is fluoro
• the dotted line in formula (II) and (IV) is a single bond.
• Z is dimethylaminomethyl or a group that may be converted to dimethylaminomethyl. In a suitable embodiment Z is dimethylaminomethyl.
• Hal is fluoro
• R is cyano
• the dotted line is a single bond
• Z is dimethylaminomethyl.
• the acylating agent used for the encymatic acylation according to the invention may suitable be one of the compounds of formula (IIIa), (IIIb) and (IIIc).
• acylating agent used according to the invention is any of the compounds of formula (IIIa) and (IIIb).
• the acylating agent used is a compound of formula (IIIa).
• the acylating agent used is a compound of formula (IIIb).
• the acylating agent is a compound of formula (IIIc).
• acylating agent is any of the above, X is suitable O.
• R 2 meaning C 1-3 -alkyl substituted one or more times with halogen is a suitable leaving group including groups such as 2,2,2-trichloroethyl and 2,2,2-trifluoroethyl, in particular 2,2,2-trifluoroethyl.
• the acylating agent of formula (IIIb) as above is a compound wherein R 2 is vinyl.
• the acylating agent of formula (IIIb) is a compound as above wherein R 1 is propyl.
• R 1 is propyl.
• This specific embodiment covers a preferred acylating agent of the invention, namely vinyl butyrate.
• the acylating agent is a compound of formula (IIIc).
• V is suitable chloro
• the acylating agent used according to the invention may also be an isocyanate of formula R 1 —N ⁇ C ⁇ O or an isothiocyanate of the formula R 1 —N ⁇ C ⁇ S.
• the acylating agent is an isothiocyanate of the formula R 1 —N ⁇ C ⁇ O.
• the acylating, agent is an isocyanate of formula R 1 —N ⁇ C ⁇ S.
• substituent R 1 in the isocyanate and the isothiocyanate as defined in any of the embodiments above, are as follows:
• the invention also covers a method for selective enzymatic deacylation of a racemic compound of formula (IV) as defined above.
• Suitable, the racemic compound of formula (IV) used is a compound wherein Y is O, or S.
• racemic compound of formula (IV) used is a compound wherein Y is O.
• racemic compound of formula (IV) used is a compound wherein Y is S.
• racemic compound of formula (IV) used is a compound wherein Y is a bond.
• the substituent R 1 in the racemic compound (IV) as defined in any of the embodiments above is as follows: C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-10 -alkoxy, C 1-10 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-10 -alkylamino and di-(C 1-10 -alkyl)amino, more suitable R 1 is C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from hydroxy, halogen, amino, nitro and cyano, preferably R 1 is C 1-10 -alkyl, preferably unbranched C 1-10 -alkyl and more preferred R 1 is unbranched C 4-10 -alkyl
• selective enzymatic acylation is carried out under conditions substantially suppressing hydrolysis.
• Hydrolysis which is the reverse reaction of the acylation reaction, takes place if water is present in the reaction system.
• selective enzymatic acylation is preferably carried out in a water-free organic solvent or almost anhydrous organic solvent (enzymes normally require the presence of some water to be active).
• enzymes normally require the presence of some water to be active.
• the examples below illustrate how addition of water affects conversion. The percentage of water allowed in a particular reaction system, may be determined by a person skilled in the art.
• the organic solvent which may be used for the acylation reaction is not particularly important as long as it does not deactivate the enzyme used.
• Suitable solvents include hydrocarbons such as hexane, heptane, benzene and toluene; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, 1,4-dioxane, tert-butyl methyl ether and dimethoxyethane; ketones such as acetone, diethyl ketone, butanon, and methyl ethyl ketone; esters such as methyl acetate, ethyl acetate, ethyl butyrate, vinyl butyrate and ethyl benzoate; halogenated hydrocarbons such as methylene chloride, chloroform and 1,1,1-trichloroethane; seconday and tertiary alcohols, such as tert-butanol; nitrogen
• hydrocarbons such as hexane, heptane, benzene and toluene, ethers such as diethyl ether, diisopropyl ether, 1,4-dioxane and tert-butyl methyl ether and esters such as vinyl butyrate
• the most preferred solvents may be aromatic hydrocarbons such as benzene or toluene and ethers, most preferred toluene and for another enzyme the most preferred solvents may be ethers such as 1,4-dioxane (see the examples below).
• the above solvents may be used singly or in a combination of two or more solvents.
• the concentration of racemic diol of formula (II) and acylating agent should not be too high as a high concentration of reagents in the solvent may lead to non-selective acylation of the racemic diol. Suitable the concentration of racemic diol and acylating reagent is each below 1.0 M, more suitable below 0.5 M, even more suitable below 0.2 M or even more suitable below 0.1 M. A person skilled in the art will be able to determine the optimal concentration of racemic diol and acylating agent.
• Selective enzymatic deacylation is preferably carried out in water or a mixture of water and an organic solvent, suitable in presence of a buffer.
• the organic solvent which may be used in the reaction is not particularly important as long as it does not deactivate the enzyme used.
• Suitable organic solvents are solvents miscible with water such as alcohols, acetonitrile, DMF, DMSO, dioxane, DME and diglyme. The skilled person will be able to identify other suitable solvents. A person skilled in the art will be able to determine the optimal concentration of racemic compound of formula (IV) used in the reaction
• the stereoselectivity of the enzyme used may be increased by carrying out the acylation or deacylation in presence of an organic acid and/or an organic base.
• the present invention also relates to a process wherein the enzymatic acylation or the enzymatic deacylation is carried out in presence of an organic base or an organic acid or a mixture thereof.
• the invention relates to a process wherein the enzymatic acylation or enzymatic deacylation is carried out in the presence of an organic acid, suitable an organic carboxylic acid.
• the enzymatic acylation is carried out in presence of an organic acid, suitable an organic carboxylic acid.
• Suitable the above mentioned organic acid is an aromatic carboxylic acid or an aliphatic carboxylic acid.
• alkyl carboxylic acids alkyl carboxylic acids, cycloalkylcarboxylic acids, cycloalkylalkylcarboxylic acids, optionally substituted phenyl-alkylcarboxylic acids and optionally substituted phenylcarboxylic acids.
• Suitable aliphatic carboxylic acids are carboxylic acids such as formic acid, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, 2-ethylbutyric acid, n-valeric acid, iso-valeric acid, pivalic acid, n-caproic acid, iso-caproic acid, decanoic acid, crotonic acid, palmitic acid, cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, phenyl-C 1-4 -alkylcarboxylic acids such as 3-phenylpropionic acid, 4-phenylbutyric acid, oxalic acid, malonic acid and tartaric acid.
• carboxylic acids such as formic acid, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, 2-ethylbutyric acid, n-valeric acid, iso-valeric acid,
• Suitable aromatic carboxylic acids includes acids such as benzoic acid, p-chlorobenzoic acid, p-nitrobenzoic acid, p-methoxybenzoic acid, p-toluic acid, o-toluic acid, m-toluic acid, naphthoic acid, phthalic acid and terephthalic acid, salicylic acid, hydrocinnamic acid for instance.
• the organic acid used to improve stereoseleselectivity of the enzyme is selected from n-propionic acid, iso-propionic acid, n-butyric acid, iso-butyric acid, iso-valeric acid, 2-ethylbutyric acid, crotonic acid, palmitic acid, cyclohexanecarboxylic acid, pivalic acid, benzoic acid and p-toluic acid, salicylic acid and 3-phenylpropionic acid.
• the carboxylic acid used is pivalic acid.
• the amount of the organic acid to be used is not particularly restricted, but the molar ratio relative to a substrate is usually 0.1 to 10, preferably 1.0 to 3.0, and more preferably 1.0 to 2.0.
• a tertiary amine may be used to improve selectivity of the enzyme, either alone or together with any of the above mentioned organic acid.
• organic base there may be mentioned, triethyl amine, pyridine, 4-dimethylaminopyridine and pyridine is preferred.
• Suitable combinations of organic acid and organic base are benzoic acid and pyridine for example.
• the amount of the tertiary amine to be used is not particularly restricted, but the molar ratio relative to a substrate is usually 0.5 to 3.0, and preferably 0.5 to 2.0.
• the enzymatic acylation or deacylation according to the invention is carried out using a hydrolase, such as a lipase, an esterase, an acylase or a protease.
• a hydrolase such as a lipase, an esterase, an acylase or a protease.
• enzymatic acylation is performed with a hydrolase, such as a lipase, an esterase, an acylase or a protease.
• a hydrolase such as a lipase, an esterase, an acylase or a protease.
• the enzymes useful according to the invention are such enzymes capable of performing R-selective acylation or S-selective acylation of the primary hydroxy group in the racemic compound of formula (II).
• enzymatic deacylation is performed with a hydrolase, such as a lipase, an esterase, an acylase or a protease.
• a hydrolase such as a lipase, an esterase, an acylase or a protease.
• the enzymes useful according to the invention are such enzymes capable of performing R-selective deacylation or S-selective deacylation of the acyl group in the racemic compound of formula (IV).
• hydrolase and “enzyme” either generally or in relation to a specific enzyme, means not only the enzyme itself, but also cultured products containing the enzyme, such as culture fluid containing a cell body, or a cultured cell body, and processed product of the cultured product (for example a crude extract, a freeze-dried microorganism or cell, an acetone dried microorganism or cell, a ground product of such microorganism or cell, or the like).
• the “enzyme” or “hydrolase” may be immobilized as the enzyme itself or as a cell body by known techniques, and may be used in immobilized form.
• the immobilization may be carried out by methods known to the person skilled in the art, such methods include, for example carrier bonding, cross linking, encapsulation and the like.
• the hydrolase is used in the form of an immobilized enzyme or Cross-Linked Enzyme Crystal (CLEC) enzymes.
• CLEC Cross-Linked Enzyme Crystal
• enzymatic acylation according to the invention may be carried out using Novozyme 435, from Candida antartica , LipoZyme TL IM from Thermomyces lanuginosus or Lipoprotein Lipase pseudomonas sp. (isolated from Pseudomonas Cepacia and obtained from Fluka), and particularly good results have been found when using Novozyme 435, from Candida antartica or Lipoprotein Lipase pseudomonas sp.
• the enzyme used is Pseudomonas sp. lipoprotein lipase, Candida antartica lipase B or Thermomyces lanuginosus lipase.
• the enzyme used is Pseudomonas sp. lipoprotein lipase or Candida antartica lipase B.
• use of one of the above mentioned enzymes according to the invention also covers the use of cultured products containing the enzyme, such as culture fluid containing a cell body, or a cultured cell body, processed product of the cultured product and any immobilized forms of these enzymes/cultured products.
• any of the above specifically mentioned enzymes according to the invention also covers the use of mutants, variants or any equivalents of the above specifically mentioned enzymes, which are capable of performing the selective acylation or deacylation according to the invention.
• the variants or equivalents thereof may be isolated from various strains of Pseudomonas, Candida or Thermomyces , or any other source, or they may be prepared by mutation of the DNA encoding the above mentioned enzymes leading to variations in the amino acid composition of the enzyme.
• Suitable the mutants or variants of the above mentioned enzymes are variants and mutants where single amino acids have been removed or replaced by other amino acids, and suitable the amino acid sequence of the variant or mutant is more than 60% identical, preferably more than 80% or most preferred more than 90% identical to the above mentioned enzymes.
• the enzyme used is Pseudomonas sp. lipoprotein lipase or a mutant or variant thereof.
• Pseudomonas sp. lipoprotein lipase is used.
• the enzyme used is Candida antartica lipase B or a mutant or variant thereof.
• the enzyme used is Candida antartica lipase B.
• the enzyme is Novozyme®435 ( Candida antartica lipase B immobilized on acrylic resin, available from the company Novozymes A/S).
• the enzyme used is Thermomyces lanuginosus lipase or a mutant or variant thereof.
• the enzyme used is Thermomyces lanuginosus lipase.
• the enzyme used is LipozymeTM TL IM, also available from the company Novozymes A/S.
• the preferred reaction conditions for enzymatic acylation/deacylation differ depending on the particular enzyme used, whether it is immobilised or not etc.
• a suitable temperature for the reaction lies between 0-80° C., more preferably between 20-60° C., or more preferred between 30-50° C.
• the amount of enzyme to be used is not particularly restricted, but is usually 0.01-1.0, preferably 0.02-0.5 and more preferably 0.02-0.3, as weight ratio relative to substrate.
• the reaction may be carried as a batch process or it may be carried out as a continuous process.
• the enzyme may be used in a plurality of batches repeatedly or continuously.
• the reaction time is not particularly restricted, and will depend on the enzyme used and the scale and type production method (batch or continues).
• the present invention also relates to an S- or R-enantiomer of a compound having the formula (IV) wherein R, Hal, R 3 , W, the dotted line and Z are as defined above,or a salt thereof.
• the optically active acyl derivative above is the S-enantiomer. According to another embodiment of the invention, the optically active acyl derivative above is the R-enantiomer.
• the R- or S-enantiomer above is a compound wherein R is halogen or cyano, preferably R is cyano.
• the R- or S-enantiomer above is a compound wherein Hal is fluoro.
• the R- or S-enantiomer above is a compound wherein the dotted line represents a single bond.
• the R- or S-enantiomer above is a compound wherein Z is dimethylaminomethyl or a group that may be converted to dimethylaminomethyl, more suitable Z is dimethylaminomethyl, and the other substituents are as defined above.
• the R- or S-enantiomer above is a compound wherein Z is dimethylaminomethyl, Hal is fluoro, the dotted line represents a single bond, and R is cyano or halogen, suitable cyano.
• the R- or S-enantiomer above is a compound wherein Y is O, or S, preferably Y is O and the other substituents are as defined above. In a further embodiment of the invention, the R- or S-enantiomer above is a compound wherein Y is S and the other substituents are as defined above.
• the R- or S-enantiomer above is a compound wherein Y is a bond and the other substituents are as defined above.
• the R- or S-enantiomer above is a compound wherein Y is NH and the other substituents are as defined above.
• R 1 is C 1-6 -alkyl, C 2-6 -alkenyl or C 2-6 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-6 -alkoxy, C 1-6 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-6 -alkylamino and di-(C 1-6 -alkyl)amino
• R 1 is C 1-4 -alkyl, C 2-4 -alkenyl or C 2-4 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-4 -alkoxy, C 1-4 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-4 -alkylamino and di-(C 1-4 -alkyl)a
• the R- or S-enantiomer as defined in any of the embodiments above is a compound wherein R 1 is as follows: C 1 -10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-10 -alkoxy, C 1-10 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-6 -alkylamino and di-(C 1-10 -alkyl)amino, more suitable R 1 is C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from hydroxy, halogen, amino, nitro and cyano, preferably R 1 is C 1-10 -alkyl, preferably unbranched C 1-10 -alkyl and more preferred R 1 is un
• an enantiomer of the diol derivative represented by the formula (II) is obtained as a mixture with the opposite enantiomer of the compound of formula (IV). This reaction mixture is then optionally separated from the enzyme.
• the present inventors have made intensive investigations and have as a result found that the enantiomer of a compound of formula (II) in the form of a salt with an acid is efficiently distributed into an aqueous layer and the opposite enantiomer of a compound of formula (IV) in the form of a salt with the acid is efficiently distributed into an organic layer when the reaction mixture is treated with a mixed solvent containing organic solvent and water in the presence of an acid.
• the invention relates to a method for the isolation and purification of an acyl derivative having the formula wherein R is cyano or a group which may be converted to a cyano group, Hal is halogen, the dotted line is a double or a single bond and Z is a group —CH 2 —N(R′R′′) wherein R′ and R′′ C 1-6 -alkyl, or R′ and R′′ are connected to each other to form a cyclic structure including the N-atom to which they are attached, or Z is a group which may be converted to a dimethylaminomethyl group, W is 0 or S and R 3 is —Y—R 1 wherein Y is a bond, O, S or NH and R 1 is C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted with one or more substituents selected from C 1-10 -alkoxy, C 1-10 -alkoxy, C 1-10
• R is halogen or cyano, preferably cyano in the method for isolation and purification above.
• Hal is fluoro in the method for isolation and purification above.
• the dotted line represents a single bond.
• Z is dimethylaminomethyl or a group that may be converted to a dimethylaminomethyl group.
• Suitable Z is dimethylaminomethyl.
• Hal is fluoro
• Z is dimethylaminomethyl
• the dotted line is a single bond
• R is cyano or halogen, preferably cyano.
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein Y is O, or S, preferably Y is O and the other substituents are as defined above.
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein Y is S.
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein Y is a bond and the other substituents are as defined above.
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein Y is NH and the other substituents are as defined above.
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein R 1 is C 1-6 -alkyl, C 2-6 -alkenyl or C 2-6 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-6 -alkoxy, C 1-6 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-6 -alkylamino and di-(C 1-6 -alkyl)amino, more preferred R 1 is C 1-4 -alkyl, C 2-4 -alkenyl or C 2-4 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-4 -alkoxy, C 1-4 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-4 -alkylamino and di-(C 1-4 -al
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein R 1 is as follows: C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-10 -alkoxy, C 1-10 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-6 -alkylamino and di-(C 1-10 -alkyl)amino, more suitable R 1 is C 1-10 -alkyl, C 2-10 -alkenyl or C 2-1O -alkynyl all of which may optionally be substituted one or more times with substituents selected from hydroxy, halogen, amino, nitro and cyano, preferably R 1 is C 1-10 -alkyl, preferably unbranched C 1-10 -alkyl and more preferred R 1 is unbranched C
• a salt of the R- or S-enantiomer of a compound having the formula (II) with an acid may be selectively extracted into an aqueous layer and a salt of the opposite enantiomer of a compound of formula (IV) with an acid may be selectively separated into an organic layer by treating, in the presence of the acid, a mixture comprising an enantiomer of formula (II) and the opposite enantiomer of formula (IV), reaction solvent and the like with an organic solvent and water, and in presence of an acid.
• the salt of the enantiomer of formula (IV) and the salt of the enantiomer of formula (II) may be separated with little loss of the desired enantiomers.
• the S-enantiomer of the compound of formula (IV) is isolated from the R-enantiomer of the compound of formula (II).
• the S-enantiomer of the diol of formula (II) is isolated from the R-enantiomer of the acyl derivatitive of formula (IV).
• the amount of water to be used is 1:2 to 1:100, preferably 1:5 to 1:50, as a ratio between the compound of formula (II) and water.
• the reaction solvent may be evaporated to reduce the amount thereof or may be substituted with another organic solvent.
• the acid which may be used in the above isolation and purification process is not particularly restricted, but for example, there may be mentioned, mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid; organic acids, in particular carboxylic acids, represented by aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, n-valeric acid, iso-valeric acid, pivalic acid, n-caproic acid, iso-caproic acid, cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, oxalic acid, malonic acid and tartaric acid; or aromatic carboxylic acids such as benzoic acid, p-chlorobenzoic acid, p-nitrobenzoic acid, p-methoxybenzoic acid, p-toluic acid, o-toluic acid, m-toluic acid, naphthoic acid, phthal
• organic acids are preferred, in particular carboxylic acids such as n-butyrate, iso-valerate, cyclohexanecarboxylic acid, pivalic acid, benzoic acid and o-toluic acid, and particularly preferred is pivalic acid.
• carboxylic acids such as n-butyrate, iso-valerate, cyclohexanecarboxylic acid, pivalic acid, benzoic acid and o-toluic acid, and particularly preferred is pivalic acid.
• carboxylic acids such as n-butyrate, iso-valerate, cyclohexanecarboxylic acid, pivalic acid, benzoic acid and o-toluic acid, and particularly preferred is pivalic acid.
• the above acids may be used singly or in a combination of two or more species.
• the amount of the acids to be used is not particularly restricted, but the molar ratio of the sum of the compounds of formula (IV) and (II) and acid, is usually
• the acid used in the present isolation and purification step may be the same as the organic acid used in the acylation or deacylation reaction according to the invention or may be a different one.
• organic solvent which may be used in the isolation and purification step, there may be mentioned, for example, hydrocarbons such as hexane, heptane, benzene and toluene; ethers such as diethyl ether, tetrahydrofuran, 1,4-dioxane, tert-butyl methyl ether and dimethoxyethane; ketones such as acetone, diethyl ketone and methyl ethyl ketone; esters such as methyl acetate, ethyl acetate, ethyl butyrate and ethyl benzoate; halogenated hydrocarbons such as methylene chloride, chloroform and 1,1,1-trichloroethane.
• hydrocarbons such as hexane, heptane, benzene and toluene
• ethers such as diethyl ether, tetrahydrofuran, 1,4-dio
• aliphatic hydrocarbons such as hexane and heptane
• aromatic hydrocarbons such as benzene and toluene
• aromatic hydrocarbons Most preferred are aromatic hydrocarbons and most preferred is toluene.
• the above solvents may be used singly or in a combination of two or more solvents.
• Temperature of the isolation and purification step is preferably at 0 to 80° C., and more preferably at 10 to 40° C. and most preferred at 20 to 30° C.
• the salt of the diol of formula (II) may be used as an aqueous solution of the salt, and if needed, it may be used as a solution in another solvent or a concentrate obtained by concentration, solvent substitution or the like operation. Furthermore, it can be used as a crystal obtained by crystallization or the like operation.
• the diol of formula (II) is be used as a free diol form obtained by the following operations: A mixture containing the diol of formula (II) and an organic solvent and/or its concentrate is obtained by treating an aqueous layer with a general base such as sodium hydroxide or potassium hydroxide to control the pH of the aqueous layer to be at least 9, preferably at least 11, then extracting the free amine form of the diol of formula (II) with an organic solvent, followed by washing and concentrating the extract.
• the chemical purity of the diol of formula (II) obtained by the series of isolation and purification method is usually at least 95%, preferably at least 97%, more preferably at least 99% and most preferably at least 99.5%.
• the compound of formula (IV) obtained by the above operations may be washed with an aqueous phase in order to improve chemical purity of the product.
• the compound of formula (IV) may be obtained as a free amine form by treating the ammonium salt of the compound of formula (IV), obtained by the above operations, with a base.
• the chemical purity of the diol of formula (IV) obtained by the series of isolation and purification method is usually at least 95%, preferably at least 97%, more preferably at least 99% and most preferably at least 99.5%.
• optical purity of the product obtained after separation of the enantiomers of formula (II) and (IV) as above, may be improved before further processing. Improvement of the optical purity may be obtained by chromatography as described in WO 03/011278 or by crystallisation of diastereomeric esters or salts with optically active acids as described in U.S. Pat. No. 4,943,590.
• the mixture of compound of formula (II) and compound of formula (IV) which is separated by the above method for isolation and purification has been prepared by the selective acylation and in another embodiment by selective deacylation according to the invention.
• the invention also relates to another novel method for the separation of the R- or S-diol of formula (II) from the acyl derivative of formula (IV) of the other enantiomer whereby the desired compound may be isolated and purified.
• acyl derivative having the formula wherein R is cyano or a group which may be converted to a cyano group, Hal is halogen, the dotted line represents a double or a single bond, Z is a group —CH 2 —N(R′R′′) wherein R′ and R′′ are C 1-6 -alkyl, or R′ and R′′ are connected to each other to form a cyclic structure including the N-atom to which they are attached, or Z is a group which may be converted to a dimethylaminomethyl group, W is O or S; and R 3 is —Y—R 1 wherein Y is a bond, O, S or NH and R 1 is C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-10 -alkoxy, C 1-10 -alkylthio, hydroxy, hal
• any of the above isolated phases may additionally be washed one or more times with an organic or an aqueous solvent, respectively to improve the chemical purity of the product.
• the S-diol of the compound of formula (II) is separated from the R-enantiomer of the compound of formula (IV).
• the S-enantiomer of the compound of formula (IV) is separated from the R-enantiomer of the compound of formula (II).
• R is halogen or cyano, preferably cyano in the method for isolation and purification above.
• Hal is fluoro in the method for isolation and purification above.
• the dotted line represents a single bond.
• Z is dimethylaminomethyl or a group that may be converted to a dimethylaminomethyl group.
• Suitable Z is dimethylarninomethyl.
• Hal is fluoro
• Z is dimethylaminomethyl
• the dotted line is a single bond
• R is cyano or halogen, preferably cyano.
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein Y is O, or S, preferably Y is O and the other substituents are as defined above.
• the compound of formula (IV) in the method for isolation and purification above is a compound, wherein Y is S.
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein Y is a bond and the other substituents are as defined above.
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein Y is NH and the other substituents are as defined above.
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein R 1 is C 1-6 -alkyl, C 2-6 -alkenyl or C 2-6 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-6 -alkoxy, C 1-6 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-6 -alkylamino and di-(C 1-6 -alkyl) amino, more preferred R 1 is C 1-4 -alkyl, C 2-4 -alkenyl or C 2-4 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-4 -alkoxy, C 1-4 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-4 -alkylamino and di-(C 1-4 -alkyl
• the compound of formula (IV) in the method for isolation and purification above is a compound wherein R 1 is as follows: C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-10 -alkoxy, C 1-10 -alkylthio, hydroxy, halogen, amino, nitro, cyano, C 1-6 -alkylamino and di-(C 1-10 -alkyl)amino, more suitable R 1 is C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from hydroxy, halogen, amino, nitro and cyano, preferably R 1 is C 1-10 -alkyl, preferably unbranched C 1-10 -alkyl and more preferred R 1 is unbranched C 4
• protic organic solvent which may be used in the isolation and purification step
• alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol and tert-butanol.
• the above solvents may be used singly or in a combination of two or more species.
• apolar organic solvent which may be used in the isolation and purification step, there may be mentioned, for example, hydrocarbons such as hexane, heptane, benzene and toluene; ethers such as diethyl ether, tert-butyl methyl ether and dimethoxyethane; halogenated hydrocarbons such as methylene chloride, chloroform and 1,1,1-trichloroethane. Among them, preferred are hydrocarbons such as hexane, heptane, benzene and toluene, and more preferred is heptane.
• the above solvents may be used singly or in a combination of two or more species.
• the mixture of the compound of formula (IV) and the diol of formula (II) used in the above method for isolation and purification has been prepared by enzymatic acylation according to the invention and in another embodiment by enzymatic deacylation according to the invention.
• optical purity of the product obtained after separation of the enantiomers of formula (II) and (IV) as above, may have to be improved before further processing. Improvement of the optical purity may be obtained by chromatography as described in WO 03/006449 or by crystallisation of diastereomeric esters or salts with optically active acids as described in U.S. Pat. No. 4,943,590.
• the present invention also relates to a process for the preparation of escitalopram having the formula or a pharmaceutically acceptable salt thereof comprising preparation of the S-enantiomer of a diol having the formula wherein R is cyano or a group which may be converted to a cyano group, the dotted line represents a double or a single bond, Z is a dimethylaminomethyl group or a group which may be converted to a dimethylaminomethyl group and Hal is halogen, or a salt thereof, or the S-enantiomer of an acylated diol having the formula wherein R, Z, the dotted line and Hal are as defined above, W is O or S, and R 3 is —Y—R 1 , wherein R 1 is C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-10 -alkoxy, C 1-10 -alky
• the S-enantiomer of formula (IIs) above or the S-enantiomer of formula (IVs) used for the preparation of escitalopram is separated from the R-enantiomer of formula (IV) and (II) respectively, before ringelosure.
• the mixture of the R- or S-enantiomer of a compound of formula (II) and the opposite enantiomer of the compound of formula (IV) obtained by enzymatic acylation has been separated from each other by the isolation and purification process according one of the above novel methods for isolation and purification.
• the mixture has been separated by the other of the above novel methods for isolation and purification.
• the mixture of the R- or S-enantiomer of a compound of formula (II) and the opposite enantiomer of the compound of formula (IV) obtained by enzymatic deacylation has been separated from each other by the isolation and purification process according one of the above novel methods for isolation and purification.
• the mixture has been separated by the other of the above novel methods for isolation and purification.
• the S-enantiomer of formula (IIs) above or the S-enantiomer of formula (IVs) used for the preparation of escitalopram is not separated from the R-enantiomer of formula (IV) and (II) respectively, before ringclosure.
• the group R means cyano or any other group which may be converted to a cyano group.
• Groups which may be converted to a cyano group include halogen such as chloro, bromo, iodo or fluoro, preferably chloro or bromo.
• cyano examples include CF 3 —(CF 2 ) n —SO 2 —O—, wherein n is 0-8, —OH, —CHO, —CH 2 OH, —CH 2 NH 2 , —CH 2 NO 2 , —CH 2 Cl, —CH 2 Br, —CH 3 , —NHR 5 , —CHNOH, —COOR 6 , —CONR 6 R 7 wherein R 5 is hydrogen or C 1-6 alkylcarbonyl, and R 6 and R 7 are selected from hydrogen, optionally substituted C 1-6 alkyl, aryl-C 1-6 alkyl or aryl and, a group of formula wherein Z is O or S; R 8 —R 9 are each independently selected from hydrogen and C 1-6 -alkyl or R 8 and R 9 together form a C 2-5 alkylene chain thereby forming a spiro ring; R 10 is selected from hydrogen and C 1-6 alkyl, R 11 is selected from
• R is halogen, in particular bromo or chloro
• conversion to a cyano may be carried out as described in U.S. Pat. No. 4,136,193, WO 00/13648, WO 00/11926 and WO 01/02383.
• WO 00/13648 and WO 00/11926 describe the conversion of a halogen or a triflate group to a cyano group by cyanation with a cyanide source in presence of a Pd or Ni catalyst.
• the bromo compound is reacted with magnesium to form a Grignard reagent, followed by reaction with a compound containing a CN group bound to a leaving group.
• a compound where R is —COOH may be reacted with chlorosulfonyl isocyanate in order to form the nitrile, or treated with a dehydrating agent and a sulfonamide as described in WO 00/44738.
• Racemic compounds of formula (II) may be prepared by the methods described in the above mentioned patents or by the alkylation method described in U.S. Pat. No. 4,136,193 or the double grignard reaction described in EP 171 943 or by analogous methods.
• Racemic compounds of formula (IV) may be prepared from racemic compounds of formula (II) by non-selective acylation using anhydrides, esters, carbonates, isocyanates or isothiocyanates as defined by formulas (IIIa), (IIIb), (IIIc), R 1 —N ⁇ C ⁇ O and R 1 —N ⁇ C ⁇ S above.
• racemic compound of formula (II) may be available in the form of an acid addition salt, such as the sulphate salt, and in this case a free base of the compound of formula (II) may be obtained by treating the salt with a base in a mixture or water and an organic solvent, to transfer the compound of formula (II) into the organic phase.
• an acid addition salt such as the sulphate salt
• a free base of the compound of formula (II) may be obtained by treating the salt with a base in a mixture or water and an organic solvent, to transfer the compound of formula (II) into the organic phase.
• R is cyano in the compounds of romula (II), (IIs), (IIr), (IV) (IVs) (IVr) and (V). If R is not cyano, conversion of the group R to a cyano group is suitably carried out after ringclosure to form a compound of formula (V).
• Hal is fluoro in the compounds of romula (II), (IIs), (IIr), (V) (Vs) (IVr) and (V). If Hal is not fluoro, conversion of the group Hal to a fluoro is suitably carried out after ringclosure to form a compound of formula (V). A procedure for carrying out this conversion is described in Speciality Chemicals Magazine, April 2003, page 36-38.
• Z groups which may be converted to dimethylaminomethyl are groups such as —CH 2 -L, —CH 2 —NO 2 , —MgHal, cyano, aldehyde, —CH 2 —O-Pg, —CH 2 —NPg 1 Pg 2 , —CH 2 —NMePg 1 , —CH 2 —NHCH 3 , —CH 2 —NH 2 , —CO—N(CH 3 ) 2 , —CH(A 1 R 12 )(A 1 R 13 ), -(A 1 R 14 )-(A 2 R 15 )-(A 3 R 16 ), —COOR 17 , —CH 2 —CO—NH 2 , —CH ⁇ CH—R 18 or —CONHR 19 , wherein Pg is a protection group for an alcohol group, Pg 1 and Pg 2 are protection groups for an amino group, R 12 and R 13 are independently selected from C 1-6 alkyl, C 2-6 alkenyl,
• Z is dimethylaminomethyl, —CH 2 -L, —CH 2 —NPg 1 Pg 2 , —CH 2 —NMePg 1 , —CH 2 —NHCH 3 , —CH 2 —NH 2 , —CO—N(CH 3 ) 2 , aldehyde or —COOR 17 in the compounds of formula (II), (IIs), (IIr), (IV) (IVs) (IVr) and (V).
• Z is dimethylaminomethyl. If Z is not dimethylaminomethyl, conversion of Z to a dimethylaminomethyl group is suitably carried out after ringclosure.
• Z is dimethylaminomethyl, —CH 2 -L, —CH 2 —NPg 1 Pg 2 , —CH 2 —NMePg 1 , —CH 2 —NHCH 3 , —CH 2 —NH 2 , aldehyde, —CO—N(CH 3 ) 2 , —COOR 17 when the dotted line represents a bond.
• the dotted line is preferably a single bond.
• Compounds wherein the dotted line represents a double bond may be converted to the corresponding compound wherein the dotted line is a single bond by the methods described in WO 01/68630. Preferably the reduction is carried out after ringolosure.
• Enantioselective ring-closure of the compounds of formula (IVs) or (IIs) to form the compounds of formula (V) may suitably be carried out by treatment of a labile ester derivative of the compound with a base such as KOC(CH 3 ) 3 and other alkoxides, NaH and other hydrides, triethylamine, ethyldiisopropylamine or pyridine, at low temperatures in an inert organic solvent, such as tetrahydrofuran, toluene, DMSO, DMF, t-butyl methyl ether, dimethoxyethane, dimethoxymethane, dioxane, acetonitrile or dichloromethane. This process is described in U.S. Pat. No. 4,943,590.
• Ringolosure of the compound of formula (IIs) is suitably carried out by treatment with a base as described above in presence of an agent capable of forming a labile group with the primary alcohol of the diol, such as methanesulfonyloxy, p-toluenesulfonyloxy, 10-camphorsulfonyloxy, trifluoroacetyloxy and trifluoromethanesulfonyloxy and halogen.
• an agent capable of forming a labile group with the primary alcohol of the diol such as methanesulfonyloxy, p-toluenesulfonyloxy, 10-camphorsulfonyloxy, trifluoroacetyloxy and trifluoromethanesulfonyloxy and halogen.
• labile groups could typically be a group selected from methanesulfonyloxy, p-toluenesulfonyloxy, 10-camphorsulfonyloxy, trifluoroacetyloxy and trifluoromethanesulfonyloxy or halogen.
• the compound of formula (IVs) is subjected to hydrolysis to form the compound of formula (IIs) with aquesous base, such as NaOH, KOH or LiOH in water or alcohol or a mixture thereof and then reacted with an activated leaving group, such as for example mesylchloride or tosylchloride in an organic solvent in the presence of an organic base.
• aquesous base such as NaOH, KOH or LiOH in water or alcohol or a mixture thereof
• an activated leaving group such as for example mesylchloride or tosylchloride in an organic solvent in the presence of an organic base.
• optical purity of the escitalopram product may have to be improved after ringclosure. Improvement of the optical purity may be obtained by chromatography on a chiral stationary phase or by crystallisation of racemic citalopram base or a salt thereof according to the methods described in WO 03/000672.
• the R-enanitiomer of the compounds of formula (II) and (IV) obtained according to the invention may be used to prepare racemic citalopram and escitalopram by ring closure in acidic environment according to the method described in WO 03/000672.
• Suitable acids for carrying out acidic ring closure are mineral acid, a carboxylic acid, a sulfonic acid or sulfonic acid derivative, more suitable H 2 SO 4 or H 3 PO 4 .
• the invention relates to a process for the preparation of racemic citalopram and/or escitalopram or a pharmaceutically acceptable salt thereof comprising preparation of the R-enantiomer of a diol having the formula wherein R is cyano or a group which may be converted to a cyano group, the dotted line represents an optional bond and Z is a dimethylaminomethyl group or a group which may be converted to a dimethylaminomethyl group and Hal is halogen, or a salt thereof, or the R-enantiomer of an acylated diol having the formula wherein R, Z, the dotted line and Hal is as defined above, W is O or S, and R 3 is —Y—R 1 , wherein R 1 is C 1-10 -alkyl, C 2-10 -alkenyl or C 2-10 -alkynyl all of which may optionally be substituted one or more times with substituents selected from C 1-10 -alkoxy, C 1-10
• the above method for conversion of R-diol to escitalopram is used for the preparation of escitalopram.
• the conversion of the group R to a cyano group, reduction of a double bond represented by the dotted line to a single bond, conversion of the group Z to a dimethylaminomethyl group and conversion of Hal to a fluoro group may be carried out as described above.
• the mixture of the R- or S-enantiomer of a compound of formula (II) and the opposite enantiomer of the compound of formula (IV) obtained by enzymatic acylation has been separated from each other by the isolation and purification process according one of the above methods for isolation and purification.
• the mixture has been separated by the other of the above methods for isolation and purification.
• the mixture of the R- or S-enantiomer of a compound of formula (II) and the opposite enantiomer of the compound of formula (IV) obtained by enzymatic deacylation has been separated from each other by the isolation and purification process according one of the above methods for isolation and purification.
• the mixture has been separated by the other of the above methods for isolation and purification.
• the S-enantiomer of formula (IIr) above or the S-enantiomer of formula (IVr) used for the preparation of escitalopram is not separated form the R-enantiomer of formula (IV) and (II) respectively, before ringclosure.
• optical purity of the escitalopram product may have to be improved after ringclosure. Improvement of the optical purity may be obtained by chromatography on a chiral stationary phase or by crystallisation of racemic citalopram base or a salt thereof according to the methods described in WO 03/000672.
• C 1-10 -alkyl refers to a branched or unbranched alkyl group having from one to ten carbon atoms inclusive, such as methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 2-methyl-2-propyl, 2-methyl-1-propyl, pentyl, hexyl and heptyl.
• C 1 6-alkyl refers to a branched or unbranched alkyl group having from one to six carbon atoms inclusive, such as methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 2-methyl-2-propyl, 2-methyl-1-propyl, pentyl and hexyl.
• C 1-4 -alkyl refers to a branched or unbranched alkyl group having from one to four carbon atoms inclusive, such as methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 2-methyl-2-propyl and 2-methyl-1-propyl.
• C 1-3 -alkyl refers to a branched or unbranched alkyl group having from one to three carbon atoms inclusive, such as methyl, ethyl, 1-propyl, 2-propyl.
• C 2-10 -alkenyl and C 2-10 -alkynyl designate branched or unbranched alkenyl and alkynyl groups, respectively, having from two to ten carbon atoms, including one double bond and one triple bond respectively, such as ethenyl, propenyl, butenyl, ethynyl, propynyl and butynyl.
• C 2-6 -alkenyl and C 2-6 -alkynyl designate branched or unbranched alkenyl and alkynyl groups, respectively, having from two to six carbon atoms, including one double bond and one triple bond respectively, such as ethenyl, propenyl, butenyl, ethynyl, propynyl and butynyl.
• C 2-4 -alkenyl and C 2-4 -alkynyl designate branched or unbranched alkenyl and alkynyl groups, respectively, having from two to four carbon atoms, including one double bond and one triple bond respectively, such as ethenyl, propenyl, butenyl, ethynyl, propynyl and butynyl.
• C 2-3 -alkenyl and C 2-3 -alkynyl designate branched or unbranched ailcenyl and alkynyl groups, respectively, having from two to three carbon atoms, including one double bond and one triple bond respectively, such as ethenyl, propenyl, ethynyl and propynyl.
• C 1-10 alkoxy, C 1-10 alkylthio, C 1-10 alkylamino and di-(C 1-10 -alkyl)amino etc. designate such groups in which the alkyl group is C 1-10 alkyl as defined above.
• the terms C 1-6 alkoxy, C 1-6 alkylthio, C 1-6 alkylamino and di-(C 1-6 -alkyl)amino etc. designate such groups in which the alkyl group is C 1-6 alkyl as defined above.
• alkyl group designate such groups in which the alkyl group is C 1-4 alkyl as defined above.
• the terms C 1-3 alkoxy, C 1-3 alkylthio, C 1-3 alkylamino and di-(C 1-3 -alkyl)amino etc. designate such groups in which the alkyl group is C 1-3 alkyl as defined above.
• Halogen means fluoro, chloro, bromo or iodo.
• aryl refers to a mono or bicyclic carbocyclic aromatic group, such as phenyl, or naphthyl, in particular phenyl.
• Aryloxy, arylthio refers to such a group wherein aryl is as defined above.
• heteroaryl refers to a 5 or 6 membered monocyclic heteroaromatic group or a bicyclic heteroaromatic group. Suitable the heteroaryl group contains 1-3 heteroatoms selected from O, S and N.
• R 0 and R 1 may together form a chain of 3 to 5 carbon atoms, thus forming an anhydride.
• cyclic structure When Z is —CH 2 —N(R′R′′) wherein R′ and R′′ connected to each other to form a cyclic structure including the N-atom to which they are attached, the cyclic structure form groups, such as groups include piperidin, pyrrolidin, morpholinyl and piperazinyl.
• HOBt means hydroxybenzotriazol and pfp means pentafluorophenol.
• Modifier Methanol with diethylamine (0.5%) and trifluoroacetic acid (0.5%).
• the toluene layer contained 583.1 g of a solution of 4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile in toluene (content of pure (S)-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile: 36.0 g, yield through the enzymatic resolution process: 41.1%, 0.105 mol).
• the combined toluene layer was washed twice with 169.0 g of water, concentrated at 60° C. under reduced pressure, to thereby obtain 64.0 g of a solution of (S)-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile in toluene.
• Said toluene solution contained 32.0 g (0.0935 mol) of (S)-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile.
• Overall yield was 36.4%.
• optical purity determined by HPLC was 98.7% ee, and chemical purity was 99.9 area %, ⁇ (R)-5-cyano-2-[dimethylamino-(4′-fluorophenyl)-hydroxybutyl] benzyl butyrate: 0.04 area %.
• a test tube equipped with a stopper was charged with 50 mg (0.146 m mol ) of ( ⁇ )-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile, 25 mg of various linds of lipases, 33 mg (0.29 m mol) of vinyl butyrate and 1 ml of toluene, and stirred at 40° C. for 16 hours.
• E-values were calculated for the substrate with the optical purity of at least 50% ee. The results are shown in Table 1.
• the results are shown in Table 2.
• a test tube equipped with a stopper was charged with 100 mg (0.292 m mol) of ( ⁇ )-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl)-3-hydroxymethyl-benzonitrile, 50 mg of Novozym 435 (product of Novozymes), 333 mg (2.92 m mol) of vinyl butyrate, 0.292 m mol of various kinds of additives and 1 ml of toluene, and stirred at the temperature of 40° C. for 16 hours.
• the results are shown in Table 3.
• a test tube equipped with a stopper was charged with 10 mg (0.029 m mol) of ( ⁇ )-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile, 10 mg of Novozym 435 (product of Novozymes), 0.29 m mol of various kinds of acyl donor and 1 ml of diisopropyl ether, and stirred at 30° C. for 16 hours. For the substrate with the optical purity of at least 30% ee, E-values were calculated. The results are shown in Table 8.
• a test tube equipped with a stopper was charged with 10 mg (0.029 m mol) of ( ⁇ )-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile, 10 mg of Novozym 435 product of Novozymes), 33 mg (0.29 m mol) of vinyl butyrate and 1 ml of various kinds of solvents, and stirred at 30° C. for 16 hours. After the reaction, converted ratios and optical purities were analyzed and E-values were calculated. The results are shown in Table 9.
• the combined toluene layer was washed three times with water (50 ml, 30 ml, 30 ml) at 20° C., and an aqueous layer containing (S)-4-[4-dimethylamino-1-(4′-fluorophenyl) -1-hydroxybutyl]-3-hydroxymethylbenzonitrile (3.5 g, 0.011 mol, extraction yield: 95%), pivalic acid salt was obtained.
• a four-necked flask equipped with stirrer and thermometer was charged with 66.7 g of a solution of 20.0 g (0.058 mol) of ( ⁇ )-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile in toluene, and the temperature thereof was controlled so as to be 40° C. Then, 5.93 g (0.058 mol) of pivalic acid, 6.62 g (0.058 mol) of vinyl butyrate, and 4.1 g of an immobilized enzyme (Novozym 435) was added into the above mixture. The reaction mixture was stirred at 40° C. for 18 hours under a slight flow of nitrogen and stirring was stopped.
• a four-necked flask equipped with stirrer and thermometer was charged with 250.0 g of a solution of 25.0 g (0.073 mol) of ( ⁇ )-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile in toluene, and the temperature thereof was controlled so as to be 40° C. Then, 5.77 g (0.073 mol) of pyridine, 8.33 g (0.073 mol) of vinyl butyrate, 9.93 g (0.073 mol) of o-toluic acid, and 5.0 g of an immobilized enzyme (Novozym 435) was added into the above mixture. The reaction mixture was stirred at 40° C.
• the combined toluene layer was washed three times with water (250 ml, 63 ml, 63 ml) at 60° C., and an aqueous layer containing (S)-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile (7.8 g, 0.0228 mol, extraction yield: 80%), o-toluic acid salt was obtained.
• a four-necked flask equipped with stirrer and thermometer was charged with 250.0 g of a solution of 50.0 g (0.146 mol) of (:)-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile in toluene, and the temperature thereof was controlled so as to be 40° C. Then, 11.5 g (0.146 mol) of pyridine, 33.2 g (0.291 mol) of vinyl butyrate, 17.8 g (0.146 mol) of benzoic acid, and 10.0 g of an immobilized enzyme (Novozym 435) was added into the above mixture. The reaction mixture was stirred at 40° C.
• the enzyme was filtrated from the enzyme reaction mixture obtained by the method according to Example 1, and washed twice with toluene.
• Thus-obtained 1174.3 g of a toluene solution containing (S)-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile (44.8 g, 0.131 mol), pivalic acid salt was added 600.3 g of water and extracted.
• Example 20-24 compared to example 19 show that the separation improves by the addition of salts.
• the enzyme was filtrated from the enzyme reaction mixture obtained by the method according to Example 1, and washed twice with toluene.
• the enzyme was filtrated from the enzyme reaction mixture obtained by the method according to Example 1, and washed twice with toluene.
• the enzyme was filtrated from the enzyme reaction mixture obtained by the method according to Example 1, and washed twice with toluene.
• Toluene solution containing 1.0 g (2.92 mmol) of (S)-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile, pivalic acid was added 13.0 mL of water and extracted.
• the solution was extracted further twice with 7.5 mL of water to obtain an aqueous solution of (S)-4-[4-dimethylamino-1-(4′-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile, pivalic acid salt.
• the enzyme was filtrated from the enzyme reaction mixture obtained by the method according to Example 1, and washed twice with toluene.

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