Lithiation and dethiacarbonylation of a heterocyclic thioamide C 6 H 4 O·C(S)NH by reaction with solid Li 2 S in the presence of hexamethylphosphoramide: synthesis and crystal structure of [C 6 H 4 O·C(S)NLi·HMPA] 2 ·C 6 H 4 (OH)NH 2

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.