Tautomerism and self-conversion of substituted 2-thiophenethiols. Substituent effects and self-thiylation mechanism

Abstract

The substituent effect on the self-thiylation of 2-thiophenethiols was studied. Experimental results and quantum chemical calculations suggested possible mechanisms for this reaction dependent on the reaction conditions.We have already discovered the self-thiylation of 2-thiophenethiol (Ia) to give a dimeric dithiolactone (Ha) [1][2][3][4]. Subsequently, we obtained products of the reaction of Ha with hydrazine (Ilia) and its derivatives (IVa-h) as well as with hydroxylamine OVi) (see our previous work [5] and present communication).Similar to dithiolactone IIa, 3,-dithiobutyrolactone reacts with hydrazine hydrate and acetone monohydrazone to give III (V, R = H) and IV (VI, R = H, X = N=CMe2), respectively (see Scheme 1).