Synthesis of Imidazol-2-ylidenes by Reduction of Imidazole-2(3<i>H</i>)-thiones

Abstract

An improved synthesis of the title compounds is reported. Reaction of the N,N-dialkylthioureas 1 with 3-hydroxy-2-butanone gives the imidazole-2(3H)-thiones 2 which on treatment with potassium in boiling tetrahydrofuran give the imidazol-2-ylidenes 3 in excellent yields.