Synthesis and antimicrobial activity of some benzofuran derivatives

The Friedel-Craft's acylation of 2,3-diphenyl-5-methylbenzofuran 1a with succinic anhydride gives beta-(2,3-diphenyl-5-methylbenzofuranoyl)propionic acid 1b. Acid 1b reacts with hydrazines yielding the corresponding tetrahydropyridazinones 2. 4,5-Dihydro-1,2-oxazin-6H-6-one 6 is formed by reaction of 1b with hydroxylamine hydrochloride. The reaction of the pyridazinone 2a with dialkyl sulfates, ethyl chloroacetate, Grignard reagents, amines in presence of formaldehyde (Mannich reaction), o-amino-phenol and thiourea has been investigated. The antimicrobial activities of compounds 1a-c, 2a-c, e, f, 4a, b and 5a, b as well as 7b are studied.