Heteropoly Acids an Efficient Catalyst for Ultrasound Promoted Synthesis of Substituted Indazole

Abstract

A clean and simple methodology was developed for the synthesis of substituted indazoles using heteropoly acids containing tungsten, molybdenum metal catalyzed condensation reaction between substituted 2-hydroxy benzaldehydes/acetophenones and hydrazine hydrate/phenyl hydrazine. The reaction conditions are optimized for two different heteropoly acids such as H₃PMo₁₂O₄₀ and H₃PW₁₂O₄₀ using conventional and ultrasound sonication method. Yield of the products improved to 92 to 95% using H₃PW₁₂O₄₀ heteropoly acid as catalyst which is reusable, cost effective and easy to handle.

Keywords:

• Heteropoly acids
• Hydrazine hydrate
• o-hydroxy acetophenones/benzaldehydes
• ultrasound and indazole

Acknowledgments

The author thanks to Dr. S. P. Lawande for help in preparing this manuscript. Authors are thanks to Principle of Shri Chhatrapati Shivaji Mahavidyalaya, Shrigonda, Ahmednagar for providing laboratory facilities for this work and thanks to SAIF Chandigarh for providing spectral analysis.

Disclosure statement

Authors do not have any conflict of interest in this work.