Synthesis of 2-arylbenzo-1,3-tellurazoles by oxidative cyclization of 2,2′-ditellurobis[N-(arylmethylene)benzenamines

Abstract

A method has been developed to prepare 2-arylbenzo-1,3-tellurazoles from bis(2-aminophenyl) ditelluride and aromatic aldehydes by oxidative cyclization following an easily implemented one pot procedure. Imines obtained by combining aldehyde and ditelluride were cyclized with phosphorous oxychloride without prior purification, resulting in the formation of benzo-1,3-tellurazoles carrying aryl or heteroaryl substituents in position 2 in yields up to 58 %. Evidence is presented for a radical reaction pathway. This method is set apart from other options by avoiding strongly reducing conditions and minimizing the synthetic effort required to prepare aryl substituted benzo-1,3-tellurazoles. An X-ray crystallographic characterization of 2-(2-quinolinyl)benzo-1,3-tellurazole indicated only weak TeˑˑˑN secondary bonding interactions.