Cyclocondensation of 2,2-dichloroethenylbenzamide and its analogs with amidines and hydrogen sulfide in the presence of bases

Available chlorine-containing enamides of the general formula Cl2C=CHNHCOR (I) easily react with benzamidine and its derivatives to give 1:1 adducts which under heating with sodium methylate transform to 2-(methoxymethyl)-4,5-diaryl-s-triazines. Reaction of compounds (I) with hydrogen sulfide in the presence of triethylamine yields a mixture of products. Only the corresponding 3,5-bis(acylaminomethyl)-1,2,4-tritiolanes were isolated from the reaction mixture in moderate yield.