OxymaPure/DIC: An Efficient Reagent for the Synthesis of a Novel Series of 4-[2-(2-Acetylaminophenyl)-2-oxo-acetylamino] Benzoyl Amino Acid Ester Derivatives
OxymaPure (ethyl 2-cyano-2-(hydroxyimino)acetate) was tested as an
additive for use in the carbodiimide (DIC) approach for the synthesis of a novel series of
α-ketoamide derivatives (4-[2-(2-acetylaminophenyl)-2-oxo-acetylamino]benzoyl amino
acid ester derivatives). OxymaPure showed clear superiority to HOBt/DIC or carbodiimide
alone in terms of purity and yield. The title compounds were synthesized via the ring
opening of N-acylisatin. First, N-acetylisatin was reacted with 4-aminobenzoic acid under
conventional heating as well as microwave irradiation to afford 4-(2-(2-acetamidophenyl)-
2-oxoacetamido)benzoic acid. This α-ketoamide was coupled to different amino acid esters
using OxymaPure/DIC as a coupling reagent to afford 4-[2-(2-acetylaminophenyl)-2-oxoacetylamino]
benzoyl amino acid ester derivatives in excellent yield and purity. The
synthesized compounds were characterized using FT-IR, NMR, and elemental analysis.
