3-Mercaptopropionic acid–nitrile imine adducts. An unprecedented cyclization into 1, 3, 4-thiadiazol-2 (3 H)-ones and-2 (3 H)-thiones

Abstract

3-Mercaptopropionic acid–nitrile imine acyclic adducts (6a–c) undergo cyclocondensation with 1,1′-carbonyldiimidazole to afford the respective 1,3,4-thiadiazol-2-(3H)-ones (7a–c). Corresponding 1,3,4-thiadiazol-2(3H)-thiones (8a–c) were likwise produced from 6a–c and 1,1′-thiocarbonyldiimidazole, with consequent elimination of the propionate moiety. The constitution of these heterocyclic products follows from analytical and spectral data and is confirmed by single crystal X-ray structure determination for 7b.