Synthesis of nitriles and symmetrical organic sulphides from biprotic carbothioamides and an α-halogenated ketone, ester or nitrile

Abstract

Thioacetamide has been used as an elegant sulphur transfer reagent for C-S-C coupling of reactive halides. Sulphur extrusion of biprotic carbothioamides to form corresponding nitriles has been reported with the help of (i) dichlorocarbene; (ii) triphenylphosphine, carbon tetrachloride, triethylamine; (iii) diethyl azocarboxylate, triphenylphosphine; and (iv) soft metal ions. 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).