Reaction of 1-alkylthio-3,3-diarylthiophthalylium salts with CH acids

It was shown that the reaction of 1-alkylthio-3,3-diarylthiophthalylium salts with Meldrum's acid, methylphenylpyrazolone, N-ethylrhodanine, and ethyl cyanoacetate does not depend on the character of the substituents in the substrate and the nature of the methylene component and leads to the corresponding condensation products with thiophthalylidene structures.