Aim and Objective: Benzodiazepines and indole fused heterocycles are pharmacologically significant
scaffolds. Trivial work on indole fused benzodiazepine compounds is reported in the literature. Hence, it is
imperative to explore the synthesis of indole-fused benzodiazepines that may act as a template for biological
studies in the future. Hence, in the present work, the synthesis of indole fused benzodiazepine derivatives was
undertaken using multi-phase nano-titania as catalyst under microwave irradiation.
Materials and Methods: MAOS technique was used to carry out the synthesis of spiro-benzo [1,4]diazepine
derivatives in the presence of multiphase nano-titania as a catalyst. Nano-titania was prepared by sol-gel
method and characterized by XRD, FT-IR, FESEM, EDS and thermogravimetric techniques. The synthesized
spiro-benzo [1,4] diazepine derivatives were identified by physical and spectral methods.
Results: Synthesized compounds were obtained in excellent yields in a short span of time. The synthesis was
also carried out in the presence of conventional catalysts in addition to nano-titania. Among all the catalysts,
the best result was obtained with nano-titania. The amount of nano-titania was optimized to be 0.05g giving 93-
95 % yield of products. The study of reusability of nano-titania revealed that it could be reused up to four times
with a negligible change in efficiency.
Conclusion: The paper reports an efficient, cost-effective and environmentally benign approach for the synthesis
of spiro-benzo [1,4] diazepine derivatives in the presence of multiphase nano-titania catalyst under microwave
Keywords: Spiro-benzo[1, 4]diazepines, o- phenylene diamine, nano- titania, microwave irradiation, isatin and p- substituted acetophenones.
Rights & PermissionsPrintExport