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Current Microwave Chemistry
ISSN (Print): 2213-3356
ISSN (Online): 2213-3364
DOI: 10.2174/2213335601666140806010137

Microwave Assisted Synthesis of New Imines of 7-Aminocephalosporinic Acid as Potent Antibacterial Agents

Author(s): A.B. Thomas, S.P. Moharil, R.K. Nanda, S.G. Dhokrat, L.K. Kothapalli and M.V. Nanwatkar
Pages 148-154 (7)
A series of new imines of 7-Aminocephalosporinic acid (7-ACA) were synthesized by fragment-based design using smaller and functionally simpler adducts like alpha-halo ketones, N-heterocycles and 7-ACA with good success to generate chemical compounds with drug-like properties effective against Staphylococcus aureus and Pseudomonas aeruginosa which are resistant to several antibiotics and are responsible for a large number of community acquired infections. In the first step, N-aryl substituted ketones were synthesized in excellent yields (90-96%) in a single step reaction (Scheme 1) with various heterocyclic rings in the presence of solvents like ethanol/DMF using microwave irradiation method in shorter reaction times (10-12 mins) with higher yields (90-95%). Further, the microwave assisted synthesis of imines of 7-ACA from corresponding ketones (Scheme 2) with ethanol as the solvent in the presence of molecular sieves resulted in target compounds with improved yield (90-94%) in short reaction times (12-14 min). The use of microwave assisted synthetic route and greener and environmentally benign solvents resulted in improvement of rates (energy savings), yields and selectivity (reduced wastes) of the target compounds.
Graphical Abstract:
Alpha-halo ketones, fragment-based design, imines of 7-ACA, microwave irradiation, N-heterocycles.
Department of Pharmaceutical Chemistry, Dr. D.Y. Patil Institute of Pharmaceutical Sciences and Research, Pimpri, Pune 18, Maharashtra, India.