Cyclization Reactions in Azole Chemistry: The Reaction of Some Azoles With o-Fluoroacetophenone, o-Fluorobenzaldehyde and o-Fluorobenzophenone

Abstract

The reactions of some azoles with o-fluoro-acetophenone , -benzaldehyde and -benzophenone in dimethyl sulfoxide solution in the presence of anhydrous potassium carbonate have been investigated. In addition to the expected substitution products, cyclization reactions frequently occurred to give carbinols in the case of the reactions of o-fluoro-acetophenone and -benzophenone, and cyclic ketones in the case of the reactions with o-fluorobenzaldehyde . Fluoren-9-ol and related carbinols containing heteroaromatic nuclie are readily converted in dimethyl sulfoxide solution into the corresponding ketones by treatment with anhydrous potassium carbonate. When treated with ethanolic alkali, 2′-(benzimidazol-1′-yl) acetophenone undergoes a remarkable transformation to give 1-(2𔈊-aminophenyl)quinolin-4(1H)-one.