Lithiation and dethiacarbonylation of a heterocyclic thioamide C6H4O·C(S)NH by reaction with solid Li2S in the presence of hexamethylphosphoramide: synthesis and crystal structure of [C6H4O·C(S)NLi·HMPA]2·C6H4(OH)NH2

Abstract

Solid Li2S reacts with a solution of [graphic omitted]H and hexamethylphosphoramide (HMPA) in toluene to give [[graphic omitted]Li·µ2-HMPA]2·C6H4(OH)NH2, 1, in which two equivalents of the organic acid have been lithiated while a third equivalent has been stripped of its CS group and di-protonated; structurally, complex 1, which can also be prepared directly by reacting BunLi, [graphic omitted]H, HMPA and NH2C6H4OH in 2:2:2:1 amounts, is unique in having a heterobifunctional ligand (NH2C6H4OH) bridging two Li+ centres in the same molecule.