Reaction of N-aryl- and imidoyl-sulphimides with diphenylcyclopropenone; synthesis of 4-pyrimidones

Abstract

SS-Dimethylsulphimides have been prepared from aniline, 4-chloroaniline, 2-aminopyridine, 2-aminopyrimidine and its 3,5-dimethyl derivative, N-phenylbenzamidine, and 2-aminobenzoxazole. The sulphimides all react readily with diphenylcyclopropenone, with elimination of dimethyl sulphide. The products from the N-arylsulphimides are amides [(2) and (3)]; the other sulphimides give 4-pyrimidone derivatives [(6a), (8), (11), and (12)]. The assignment of structure (6a) to the adduct from SS-dimethyl-N-2-pyridylsulphimide and diphenylcyclopropenone is supported by a study of the effect of added shift reagent [Eu(fod)₃] on the n.m.r. spectrum. An analogous adduct (6b) is formed by the reaction of this sulphide with diphenylcyclopropenethione.