ChemInform Abstract: THE CYCLODESULFURIZATION OF THIO‐COMPOUNDS. PART 12‐ A NEW SIMPLE METHOD FOR THE SYNTHESIS OF Nα‐SUBSTITUTED BENZIMIDAZOLES FROM THIOUREA DERIVATIVES

Synthesis, Reactions, and Pharmacological Applications of 2-Aminobenzimidazoles: An Update

“…The cyclisation carried out with help of lead oxide and mercuric oxide in dry chloroform. Dimethyl sulfate and methyl iodide in ethanol mercury(II)chloride were proposed as a reagent [9][10][11][12][13]. The cyclization of (o-aminophenyl) thiourea was resulted in benzimidazole thione as a product, instead of synthesizing unsubstituted 2-aminobenzimidazole [14,15].…”

Concise on Some Biologically Important 2-Substituted Benzimidazole Derivatives

“…The cyclization was initially carried out in lead oxide and mercuric oxide in dry chloroform [44]. Afterward, methyl iodide in ethanol Mercury (II) chloride and dimethyl sulphate were thereafter proposed as reagents [45][46][47][48][49]. Attempts to synthesize unsubstituted 2aminobenzimidazole by cyclization of (o-aminophenyl) thiourea were unsuccessful and instead of the desired product they resulted in benzimidazole thione [50,51].…”

NaI-Mediated Electrochemical Cyclization–Desulfurization for the Synthesis of N-Substituted 2-Aminobenzimidazoles

“…Conventional methods for preparing N -substituted 2-aminobenzimidazoles 3 involve an addition step followed by desulfurization between either N -substituted o -phenylenediamines 1 or o -phenylenediamines 4 with isothiocyanates 2 . Regarding o -phenylenediamines 4 as starting materials, the process requires the utilization of variety reagents, including N , N ′-dicyclohexylcarbodiimide (DCC), diacetoxyiodobenzene (DIB/Et 3 N), CH 3 I, 1,1′-(ethane-1,2-diyl)­dipyridium bistribromide (EDPBT/Et 3 N), TsCl/NaOH, HgO, benzotriazol-1-yloxytris­(dimethylamino)­phosphonium hexafluoro-phosphate (BOP), SnCl 2 , and an ultrasonic method using Ph 3 P/I 2. …”