Thiono and Dithio Esters, 41. - Reaction of Dithiono Malonic Esters with Electrophiles

Article abstract of DOI:10.1002/ardp.19883211209

Dithiono malonic esters 1 react with alkali alkoxides to form the stable alkali salts 2.According to an X-ray analysis for the N,N,N',N'-tetramethylformamidinium salt 18 their anions adopt a trans,s-trans configuration in the crystalline state.By NOE experiments the same configuration is confirmed for solutions (DMSO or D2O).Alkylation of 2, however, gives rise to the Z-configurated thiono acrylic esters 4.By oxidation of 1a with tert.-butyl hypochlorite or iodine the 1,2-dithiolium salts 5 and 7 were obtained.The reaction of 1a with N,N-dimethyl formamidediethylacetal (8) in ethanol leads to the formation of the dimethylaminomethylene compound 12, in ether the formamidinium salt 18 precipitates.The latter decomposes to N,N-dimethylformamide 20 and the thiono acrylic ester 21.