O-Haloacetophenones 1 react with carbon disulfide in the presence of sodium hydride and an alkylating reagent to ketene S, S-acetals 3 and 4. The formation of 1-thiochromones 5 is possible, when the reaction is carried out at 100°. Treatment of 3a with aniline and guanidine, respectively, leads to the ketene N, N-acetal 6 and the 2-aminopyrimidine 7, respectively Reaction of 1 with phenyl isothiocyanate/sodium hydride and following ...
