Silica-Supported 1,3-Dibromo-5,5-dimethylhydantoin (DBH) as a Useful Reagent for Microwave-Assisted Aromatization of 1,3,5-Trisubstituted Pyrazolines under Solvent-Free Conditions

Abstract

1,3,5-Trisubstituted pyrazolines are rapidly and conveniently oxidized to their corresponding pyrazoles by 1,3-dibromo-5,5-dimethylhydantoin (DBH) under microwave irradiation and solvent-free conditions. The presence of silica gel as a supporting agent is shown to be effective in reducing the reaction times and increasing the yields.

Key words

pyrazolines - 1,3-dibromo-5,5-dimethylhydantoin (DBH) - aromatization - solid-surface - microwave irradiation

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