Preparation of optically active alanine ester derivatives comprises reacting lactic acid ester sulfonate with aniline

The preparation of optically active alanine ester derivatives (I) comprises reacting optically active lactic acid ester sulfonate (II) with aniline (III) at 100-190 deg C with or without the presence of solvents or diluents and in the presence of organic carbonates. The preparation of optically active alanine ester derivatives of formula (I) comprises reacting optically active lactic acid ester sulfonate of formula (II) with aniline of formula (III) at 100-190 (especially 120-140) deg C with or without the presence of solvents or diluents and in the presence of organic carbonates. R1-R3 = 1-6C alkyl; R4 = 1-12C alkyl or a 1-3C alkyl mono- or di-substituted aryl group An Independent claim is also included for a preparation of (II) comprising reaction optically active lactic acid ester with alkyl- or aryl-sulfonyl chloride in the presence of a tertiary amine.