Investigation of the Reaction of Chloroacetyl Chloride with 1,5-Benzothiazepines: Selective Synthesis of Azeto[2,1-d][1,5]benzothiazepines by Green Chemical Methods and Their Biological Activity

Abstract

An efficient and exclusive synthesis of the tricyclic azeto[2,1-d][1,5]benzothiazepine ring system has been developed. By use of microwave irradiation in the presence of basic alumina, the reaction time has been brought down from hours to minutes with improved yields in comparison to conventional heating. Antimicrobial screening of the synthesized compounds has shown promising activity.

Keywords:

• 1,5-Benzothiazepines
• β-lactams
• microwaves
• antifungal activity

Financial assistance from CSIR and UGC New Delhi is gratefully acknowledged. One of us (R. S.) is thankful to CSIR for the award of a Research Associateship. We are also thankful to Department of Pathology, Agricultural Research Station, Durgapura, and Jaipur, for antifungal screening and RSIC, CDRI, Lucknow, and NIPER Chandighar for the elemental and spectral analyses.

Notes

∗Procedure A-D as described in the experimental section.

^a Time (12+3) indicates first irradiation for 12 min. gives compound 3 (detected by TLC) and then further irradiation after adding chloroacetyl chloride for 3 min yields 5a;

^b Using solvent system benzene: ethyl acetate (8 : 2).

^a min. value-best and significantly superior compound;

^b -at par with min. values-when difference of ^a ; and other significant value is under the CD%.