Fluorinated phosphoric acid as a versatile effective catalyst for synthesis of series of benzimidazoles, benzoxazoles and benzothiazoles at room temperature

Abstract

The present work describes synthesis of a series of benzimidazoles, benzoxazoles and benzothiazoles through the cyclization of 1, 2-phenylenediamine, 2-aminothiophenol, or 2-aminophenol with aryl, aliphatic and heteroaryl aldehydes. The present synthetic protocol is very much efficient in presence of 5 mol % fluorophosphoric acid as a catalyst in ethanol solvent at room temperature. Shorter reaction time, simple work-up technique, high yields and easy availability are specific compensations of the present synthetic approach.

GRAPHICAL ABSTRACT

Keywords:

• Fluorophosphoric acid
• cyclization
• room temperature
• benzimidazoles
• benzoxazoles
• benzothiazoles

Acknowledgements

Authors are thankful to the management and principals of their respective colleges for encouragement & assistance. They are also thankful to IICT Hyderabad and Solapur University for proving spectral data.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

The authors would like to acknowledge CNMS, Jain University and Nano Mission, DST, Government of India, for financial support SR/NM/NS-20/2014. The authors also gratefully acknowledge Centre for Nano and Material Sciences (CNMS), JAIN University, Bangalore for partially funding support through the basic research grant of JAIN (No.II(39)/17/005/2017SG).