title: The cyclodesulphurization of thio-compounds. Part 12: A new simple method for the synthesis of N-alpha-substituted benzimidazoles from thiourea derivatives.
abstract: A new facile method has been established for the synthesis of N-alpha-substituted benzimidazoles by cyclodesulphurization of various N-[2-amino]-phenyl-N'-alkyl, -aryl and -aralkylthiourea derivatives with mercuric salts. Besides mercuric chloride, the use of mercuric oxide and mercuric acetate was successful for the first time in effecting ring closure of thio-compounds. The attempted use of acid condensing agents showed phosphoryl chloride to be less efficient than mercuric salts in conducting the cyclization reactions and led to poor yields of cyclized products.
mesh_terms: D001562:Benzimidazoles / Q000032:analysis / Q000138:chemical synthesis*; D003500:Cyclization; D008628:Mercury; D008722:Methods; D013455:Sulfur; D013890:Thiourea / Q000031:analogs & derivatives* / Q000138:chemical synthesis
chemical_list: D001562:Benzimidazoles; D013455:Sulfur; D008628:Mercury; D013890:Thiourea