A new synthesis of unsubstituted, 4(5),and 4,5-substituted 1H-imidazoles.

Solvent-Free One-Pot Synthesis of 2-Thioxodihydro-1H-Imidazole-4,5-Dione using a Multi-Component Reaction of Oxalyl Chloride

“…2,3 For example, the reaction of oxalyl chloride with dialkyl thiourea in ethanol and reflux condition produce 2-thioxodihydro-1Himidazole-4,5-dione in good yield. 4,5 The 1H-imidazole system can be found in many medical compounds such as the fungicide ketoconazole, [6][7][8] the benzodiazepine antagonist flumazenil, [9][10][11][12] the antineoplastic drug dacarbazine, 13 the antibiotic metronidazole, 14 the antiulcerative agent cimetidine, 15 the antihyperthyroid drug methimazole, 16 the prohormone thyroliberin, 17 the muscarinic receptor agonist pilocarpine 18 and the hypnotic agent etomidate. 19 Continuing our efforts towards the facile preparation of biologically active target molecules through multicomponent reactions, we synthesised some 1H-imidazole derivatives via a three component reaction of primary amines, aryl isothiocyanate and oxalyl chloride at 70 °C under solventfree conditions (Scheme 1).…”