Medium Buffer Effects on the Condensation of l-Cysteine and Aryl Nitriles to (R)-2-Aryl-4,5-dihydrothiazole-4-carboxylic Acids

The condensation of l-cysteine and aryl nitriles to (R)-2-aryl-4,5-dihydrothiazole-4-carboxylic acids in buffered media was reinvestigated. Pure products (yields of 58–95%; up to 99% ee) were obtained in a NaHCO₃/NaOH-buffered aqueous alcoholic medium.