Solid- and solution-state carbon-13 nuclear magnetic resonance studies of a series of sulphur-containing heterocycles

Abstract

Thiin-4-one (3a) and 3-methoxycarbonylthiin-4-one (7a) together with their dihydro- and tetrahydro-analogues and a number of the corresponding sulphoxides and sulphones have been studied using solution- and solid-state ¹³C n.m.r. These investigations highlight the usefulness of solid-state ¹³C n.m.r. spectroscopy for the study of keto–enol tautomerism in β-keto esters and provide new information concerning the aromaticity of thiin-4-ones.