Process for the preparation of carboxyalkylthiosuccinic acids

摘要

Preparation of a carboxyalkyl thio-succinic acid of formula: HOOC-(CH2)n-S-CH-(CH(R)(COOH)-COOH; (Where: n = 1-3; R = H or methyl); involves reacting a mercapto-ester of formula: HS-(CH2)n-COOR<1>; (where: n = 1-3; R<1> = 1 - 4C alkyl); with maleic- or citraconic- acid, or their anhydrides. Also claimed is preparation of carboxyethyl-thiosuccinic acid (CETSA) from methyl mercapto-propionate (MMP) and maleic acid or anhydride.