[(L)Proline]₂Zn Catalysed Synthesis of 1,5‐Benzodiazepine Derivatives Under Solvent‐Free Condition

Abstract

This communication demonstrates that a novel Lewis acid complex, Zn[(L)proline]₂, catalysed one pot synthesis of 1,5‐benzodiazepine derivatives under solvent‐free conditions. The efficiency of the catalyst has been examined by conventional method and microwave irradiation technique. 1,5‐Benzodiazepine is obtained in moderate to good yield (up to 93%) in all the reactions within a shorter reaction time under microwave irradiation. The recycling ability of the catalyst has also been evaluated. The catalyst is reusable up to five times without appreciable loss of its catalytic activity.

Keywords:

• 1,5‐Benzodiazepine
• Lewis acid
• Multi component reaction
• One‐pot condensation
• Solvent‐free
• Zn‐proline

Acknowledgment

The authors are grateful to University Grants Commission (UGC), New Delhi for financial support in the form of a major sponsored project. One of the authors (V. Sivamurugan) thanks the Council of Scientific and Industrial Research (CSIR), New Delhi for the award of senior research fellow.