Microwave-assisted reactions of 4-[(4-oxochromen-3-yl)methylene]-2-phenyl-1,3-oxazol-5(4H)-ones with nitrogen bases

Abstract

The microwave-assisted reactions of 4-[(6-R-4-oxochromen-3-yl)methylene]-2-phenyl-1,3-oxazol-5(4H)-ones 1a-1c with N-bases are described. Substituted benzamides 2a2c were prepared by reaction of 1a with primary amines in the presence of acetic acid and potassium acetate. Benzamides 3a and 3b were synthesized by reaction of 1b with piperidine and morpholine, respectively. Oxazolone 1 reacted with o-phenylenediamine to give benzoimidazole derivative 4. 3-Benzamido-1-[(pyridin-4-yl)carboxamido]-2,5-dioxo-3,10adihydro-2H-chromeno[2,3-b]pyridine 5 was prepared by reaction of 1a with isoniazid in acetic acid and 5-[(6-bromo-4-oxochromen-3-yl)methylene]-3-phenyl-2,5-dihydro-1H[1,2,4]triazine-6-one 6 was synthesized by reaction of 1c with hydrazine in methanol.