27655-95-4Relevant articles and documents
Process for the preparation of optically active alpha-acrylalkanoic acids and novel intermediates thereof
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, (2008/06/13)
A new enantioselective process is described for preparing optically active alpha-arylalkanoic acids by: (a) halogenation on the aliphatic carbon atom alpha to the ketal group, of ketals of formula STR1 in which Ar represents an aryl, optionally substituted; R represents a C1 -C4 alkyl; R1 and R2, represents a hydroxy, a O- M+, OR3 or NR4 R5 group; the carbon atoms indicated by an asterisk both simultaneously are in (R) or (S) configuration. This reaction is diastereoselective, so that a mixture of alpha-haloketals is obtained in which one of the two epimers prevails, and generally strongly prevails, over the other. (b) rearrangement of the haloketals of formula STR2 in which X is Cl, Br or I to alpha-arylalkanoic acids in a single stage or in two successive stages, by way of esters of formula STR3 The compounds (A) and (C) are all new compounds. The rearrangement step (b) may be performed under new, inventive conditions. The esters of formula (C) have pharmacological activity analogous to that of the corresponding alpha-arylalkanoic acids.
Optical resolution of racemic mixtures of alpha-naphthylpropionic acids and derivatives of said acids
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, (2008/06/13)
A new process for the optical resolution of racemic mixtures of α-naphthylpropionic acids of formula STR1 wherein R1 is (C1-6) alkyl and R2 represents hydrogen or a halogen atom comprises reacting a racemic mixture of a compound of formula II STR2 wherein R1 and R2 have the above seen meanings and R3 is a reactive group, with an optically active aminoacid of formula STR3 wherein R4 represents a (C1-8) alkyl, phenyl, substituted phenyl, benzyl, substituted benzyl or carboxy, and m is an integer from 0 to 4, to give a pair of diastereoisomeric amides of formula STR4 wherein R1, R2, R4 and m have the above seen meanings, and M is a hydrogen atom or a cation of an alkali metal or a cation of an organic base. Compounds IV are resolved into the single diastereoisomeric amides d,d or 1,d, or d,1 or 1,1. Acid hydrolysis gives the optically active compound I.
Process for the optical resolution of racemic mixtures of α-naphthyl-propionic acids
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, (2008/06/13)
A new process for the optical resolution of racemic mixtures of α-naphthyl-propionic acids of formula STR1 This process comprises reacting a racemic mixture of a compound of formula STR2 with an optically active substance of formula R4 --NH2 (III), said substance being a β-aminoalcohol, thus forming a pair of diastereoisomeric amides which are resolved into the single diastereoisomers by fractional crystallization. The obtained single diastereoisomeric amide is then hydrolyzed to give the desired optically active α-naphthyl-propionic acid of formula STR3 In the above compound I→III and VI, R1 is (C1-6)alkyl, R2 stands for hydrogen, halogen, mercapto, (C1-6)alkylthio, phenylthio, benzylthio, (C1-6)alkylsulfonyl, benzenesulfonyl, benzenesulfonyl substituted by halogen or (C1-4)alkyl, R3 is a reactive group and R4 is the residue of a primary or secondary alcohol.
