The Photolyses of Fully Aromatic Amides

Abstract

The 254 nm photolyses of ethanol solutions of four fully aromatic amides were followed by liquid chromatography and u.v. spectroscopy, and quantum yields for the major products calculated. The photolysis of benzanilide was examined in detail at various wavelengths and in several solvents, both in the presence and absence of oxygen. Quantum yields for 2- and 4-aminobenzophenones and products from free radical precursors decreased with increasing solvent polarity and with increasing incident wavelength of irradiation. Oxygen had no affect on aminobenzophenone formation but produced benzoic acid from free radical fragments which escaped the solvent cage. The results are tentatively interpreted in terms of an energy dependent radiationless conversion to a reactive 1π*-carbonyl which then cleaves the N—C bond to give caged free radicals, rather than by a concerted, nonradical rearrangement.