An Efficient One‐Pot Synthesis of 1, 5‐Benzodiazepine Derivatives Catalyzed by TBAB under Mild Conditions

Mohammad A Baseer,Asgar Jafar Khan

doi:10.1155/2012/657439

Abstract

2,3‐Dihydro‐1H‐1,5‐benzodiazepines were synthesized by reaction of o‐phenylenediamine with ketones (acyclic / cyclic) under solvent free conditions in the presence of tetra butyl ammonium bromide (TBAB) in short reaction time with excellent yield.

Highlights

Benzodiazepines and their derivatives are important class of nitrogen containing heterocyclic compounds because of their pharmacological properties[1]
Keeping in mind in the present study we have develop a one pot synthesis of 1, 5-benzodiazepines by condensation of o-phenylenediamine with ketones under mild conditions catalyzed by tetrabutylammonium bromide (Scheme 1)
Infrared spectra were recorded on a PerkinElmer infra red spectrophotometer using KBr discs, TLC was performed on silica gel coated aluminum plates using ethyl acetate and pet ether (3:7 v/v) as eluent, melting points were determined on an electronic melting point apparatus and were uncorrected

Summary

Introduction

Benzodiazepines and their derivatives are important class of nitrogen containing heterocyclic compounds because of their pharmacological properties[1]. According to the literature survey several synthetic methodology have been introduced for the synthesis of benzodiazepines, these include condensation of o-phenylenediamine with α-β unsaturated carbonyl compounds[7], β haloketones[8] or ketones in the presence various catalyst such as BF3OEt9, NaBH410, PPA- SiO211, MgO-POCl312, Yb(OTf)[313], amberlyst-1514, Ag3PW12O4015, solid super acid sulphated zirconia[16], acetic acid – under MWI17, AgNO318, zinc montmorilonite as catalyst at r.t19 and ionic liquid[20,21].

Results

Conclusion