The interaction of dimethyl sulfoxide with N-benzoyl amino acids

Abstract

The interaction of dimethyl sulfoxide with N-benzoyl amino acids in deuterochloroform has been investigated by ¹³C n.m.r. spectroscopy. Examination of the chemical shifts of the benzene ring reveals that intermolecular hydrogen bonding between dimethyl sulfoxide and the amido-hydrogen atom increase the effective steric size of the amino hydrogen, resulting in an increase in the torsional angle between the benzene ring and the C(O)NHCH(R)COOH side chain. Self-association of N- benzoyl amino acids in deuterochloroform occurs largely through two COOH...O=C hydrogen bonds and does not involve intermolecular hydrogen bonding to the N-H proton.