One-Pot Synthesis of 2-Substituted Benzoxazoles Directly from Carboxylic Acids
Dinesh Kumar A , Santosh Rudrawar A and Asit K. Chakraborti A BA Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S. A. S. Nagar, Punjab 160 062, India.
B Corresponding author. Email: akchakraborti@niper.ac.in
Australian Journal of Chemistry 61(11) 881-887 https://doi.org/10.1071/CH08193
Submitted: 6 May 2008 Accepted: 14 September 2008 Published: 5 November 2008
Abstract
Methanesulfonic acid has been found to be a highly effective catalyst for a convenient and one-pot synthesis of 2-substituted benzoxazoles by the reaction of 2-aminophenol with acid chlorides, generated in situ from carboxylic acids. Aryl, heteroaryl, and arylalkyl carboxylic acids provided excellent yields of the corresponding benzoxazoles. The reaction conditions were compatible with various substituents such as chloro, bromo, nitro, methoxy, cyclopentyloxy, phenoxy, thiophenoxy, and conjugated double bonds. Benzoxazole formation was found to be general with respect to substituted 2-aminophenols.
Acknowledgements
The author (S.R.) thanks DST, New Delhi, India, for the award of Senior Research Fellowship.
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