Patent ID: 6407281
Filing Date: 2002-06-18
Classification: C07B,C07C,Y02P

Abstract:
A process for producing an optically active cysteine derivative represented by the general formula (2): wherein R1 represents an amino-protecting group of the urethane or acyl type, R0 represents a hydrogen atom or, taken together with the above R1, an amino-protecting group, R2 represents a univalent organic group selected from the group consisting of a substituted or unsubstituted alkyl group containing 1 to 7 carbon atoms, a substituted or unsubstituted aryl group containing 6 to 10 carbon atoms and a substituted or unsubstituted aralkyl group containing 7 to 10 carbon atoms, R3 represents a univalent organic group capable of functioning as an ester-type carboxyl-protecting group by its being included in the structure represented by â€”COOR3 and * represents the position of an asymmetric carbon atom,which comprisesreacting a D-form or L-form optically active amino acid derivative represented by the general formula (1): â€ƒwherein R0, R1, R2 and * are defined above, with an alcohol represented by the general formula (3): R3OHâ€ƒâ€ƒ(3) wherein R3 is as defined above, and a strong acid and/or a thionyl halide to syntheside a D-form or l-form optically active cysteine derivative represented by said general formula (2), extracting the optically active cysteine derivative of the general formula (2) from the reaction mixture using an extraction solvent to recover an organic phase containing said optically active cysteine derivative (2), wherein addition of an inorganic salt and/or warming treatment is applied to thereby cause separation of said organic phase and an aqueous phase, and recovering said optically active cysteine derivative (2) from said organic phase the procedural series from said reaction to said recovery being carried out under a condition such that the medium contracting the above optically active cysteine derivative (2) is within the range from acidic to weakly basic to thereby recover the above optically active cysteine derivative (2) from the reaction mixture while suppressing the decomposition that racemization thereof.