ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A simple and metal-free one-pot synthesis of 2-substituted-1H-4-carboxamide benzimidazole using 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine(PYTZ) as catalyst

Li-Jie Zhang, Kang Yang, Chun-Yu Li, and Ya-Quan Sun

Yancheng Teachers University, Yancheng, China

E-mail: sunyaquan@hotmail.com

Abstract: In this work, a simple and green method for the convenient synthetic protocol of 2-substituted-1H-4-carboxamide benzimidazole was reported from 2,3-diaminobenzamide and a variety of aldehydes by condensation. The results showed that 2,3-diaminobenzamide and aldehydes could react under visible light irradiation at ambient temperature in the presence of PYTZ and pumping air (or other oxidant) to obtain the desired compound with simple workup. The structures of 20 synthesized compounds were determined by NMR, IR and HRMS (new compound) techniques. The method was efficient, metal free, green, and selective.

Keywords: 2,3-diaminobenzamide ; Visible light irradiation ; PYTZ ; Air ; 2-Substituted-1H-4-carboxamide benzimidazole 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-019-00821-x

Chemical Papers 73 (11) 2697–2705 (2019)