Synthesis and Antimicrobial Activity of Novel Series of Pyrazoline Derivatives Bearing 1,4- Benzoxazinone

Abstract

The starting compound 2H-benzo [1,4]oxazin-3(4H)-one (1) was prepared from o-aminophenol (A), chloroacetyl chloride (B), benzyltriethylammoniumchloride, chloroform, and sodium hydrogen carbonate upon refluxing for 12 h at 55 o C, 1 was refluxed for 12 h with ethyl bromo acetate, acetonitrile, potassium carbonate, TBAI to furnish ethyl 2-(3-oxo-2H-benzo[1,4]oxazin-4(3H)-yl)acetate (2) and 2 was stirred for 12 h with lithium hydroxide and THF to furnish 2-(3-oxo-2H-benzo[1,4]oxazin-4(3H)-yl) acetic acid (3). The different Pyrazole compounds (4a-e) and secondary amines (4f-l) derivatives were synthesized by refluxing with hydroxy benzotriazole (HOBT), EDC HCl, DCM and triethylamine with 3 for 14 h. The synthesized compounds were characterized by their physical and spectral data and subjected to antimicrobial evaluation.