Supported Nitric Acid on Silica Gel and Polyvinyl Pyrrolidone (PVP) as an Efficient Oxidizing Agent for the Oxidation of Urazoles and Bis-urazoles

Abstract

A method for the oxidation of a good range of urazoles and bis-urazoles to the corresponding triazolinediones by supported nitric acid on silica gel (SiO₂-HNO₃) and/or polyvinyl pyrrolidone (PVP-HNO₃) is described. Reactions have been carried out heterogeneously at room temperature in dichloromethane with good to excellent yields.

Keywords:

• Bis-urazoles
• oxidation
• polyvinyl pyrrolidone
• triazolinediones
• urazoles

ACKNOWLEDGMENT

We are grateful to Ilam University, Ilam, Iran, for research facilities and financial support of this research project.

Notes

^a I and II refer to grams of PVP-HNO₃ and SiO₂-HNO₃.

^b Isolated yields.

^c Conversion.