Synthesis and reactions of some novel 4-biphenyl-4-(2//)-phthalazin-l-one derivatives with an expected antimicrobial activity

In this study reaction of l-(biphenyl-4-carbonyl)benzoic acid (1) with hydrazine hydrate, phenyl hydrazine, acetyl hydrazine and benzoyl hydrazine in boiling dry benzene gave the corresponding 4-biphenyl-4-yl-(2H)-phthaIazin-l-one (2a-d), respectively. The structure of 2c was established via its reaction with 2-chlorobenzaldehyde, 2-nitrobenzaldehyde in ethanol to give the chalcones 3a, b, respectively. On the other hand, the cyclocondensation of the acid 1 with semicarb-azide and thiosemicarbazide in sodium acetate gave phthalazinone amide / thioamide 4a, b, respectively. The reaction of 1 with hydroxyl amine hydrochloride in different media was also studied, to give the oxime derivative 5, which was readily converted to benzooxazin-1-one derivative 6 by boiling in acetic anhydride. Compound 6 was also obtained, when the acid 1 was reacted with hydroxyl amine hydrochloride in boiling pyridine. In addition, the phthalazinone derivative 2a reacted under Mannich reaction condition with phthalimide, morph line, o-crezole and B-naphthol