Amino Acids and Peptides. III. A New Synthetic Approach to N-Acylated a-Amino Aldehydes from N-Acylated α-Amino Acids by Catalytic Reduction of Their Mixed Carbonic-Carboxylic Acid Anhydrides with Palladium-Charcoal

Abstract

Mixed carbonic-carboxylic acid anhydrides prepared from N-acylated a-amino acids and ethyl chloroformate in tetrahvdrofuran were reduced to the corresponding N-acylated a-amino aldehydes with palladium-charcoal under hydrogen bubbling. The optimum conditions found for N-acetyl-L-alanine were applied to the conversion of several kinds of N-acylated x-amino acids to their corresponding aldehydes, as shown in Table II. It was found that considerable racemization occurred under the present reduction conditions.Oxidation of some N-acylated β-amino alcohols with dimethylsulfoxide in the presence of dicyclohexylcarbodiimide and phosphoric acid was also studied.