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Thioacetamide has been used as an elegant sulphur transfer reagent for C-S-C coupling of reactive halides.1–4 Sulphur extrusion of biprotic carbothioamides to form corresponding nitriles has been reported with the help of (i) dichlorocarbene;5 (ii) triphenylphosphine, carbon tetrachloride, triethylamine;6 (iii) diethyl azocarboxylate, triphenylphosphine;7 and (iv) soft metal ions.8 Here, we report that under non-hydrolytic conditions viz. DMF/OEt, EtOH/OEt and DMF/Et3N, biprotic carbothioamides (1, R=CH3, C6H5, CH2C6H5) react with bromoacetophenone (2, Z=COC6H5), ethyl bromoacetate (2, Z=COOEt).

Ethyl-α-cyano-β-aminoacrylates (I) have been used as intermediates in the synthesis of pyrimidine derivatives1,2 and I(R=H,CH3, C6H5) have been obtained by the condensations of ethyl cyanoacetate with amidines and iminoethers, in relatively poor yields.2 We now report that both biprotic and monoprotic carbothioamides-thioformamide, thiobenzamides, phenylthioacetamide, quinazolin-4(3H)-thione and pyrrolidin-2(1H)-thione condense with ethyl bromocyanoacetate, with extrusion of sulphur, to form ethyl α-cyano-β-aminoacrylate (I, R=H), ethyl α-cyano-β-aminocinnamates (I, R=-C6H5,-C6H4-OCH3, -C6H4-NO2,P), ethyl α -cyano-β-amino-β-benzylacrylate (I, R=-CH2C6H5), ethyl-α-cyano Δ4(3H), quinazolineace tate (II) and ethyl α-cyano-Δ2,α pyrrolidineacetate (III) (Table) respectively.