Reactions of heterocycles with thiophosgene. Part III. 5-Isothiocyanatopenta-trans-2,cis-4-dienal, a product obtained from pyridine

Abstract

Pyridine undergoes ring scission when treated with thiophosgene and barium carbonate to give the products of both kinetic and thermodynamic control, i.e. the trans,cis- and trans,trans-5-isothiocyanatopenta-2,4-dienals, respectively. The reactions of the trans,cis-diene (1) with a wide variety of nucleophiles invariably give thioamides and anils. There was no evidence of any cyclisation to 1,2-dihydro-2-thioxopyridine-3-carbaldehyde (7).