Reactions of Benzoyl Isothiocyanate with Active Methylene Reagents: A Novel Synthesis of Thiophene, Thiazoline and Thieno[2,3‐d]Pyrimidine Derivatives

Various derivatives of thiophene, thiazoline and thienopyrimidine have been synthesized via the reaction of active methylene reagents (la‐j) with benzoyl isothiocyanate in the presence of potassium hydroxide, followed by the subsequent treatment of the potassium salt intermediates 2a‐j with phenacyl bromide or ethyl chloroacetate. The stability of the formed adducts 3 and 12 or their selective cyclization depends on both the nature of the active methylene reagent and the α‐halocarbonyl compounds.