Synthesis and characterization of quinazoline derivatives: search for hybrid molecule as diuretic and antihypertensive agents.

To explore the pharmacological and structure-activity relationship of a series of N-substituted-(4-oxo-2-substituted-phenylquinazolin-3-(4H)-yl), substituted benzene sulfonamide derivatives (1-25) were synthesized from substituted anthranilic acids derived amino quinazolines and substituted benzene sulphonamides. All the synthesized compounds were evaluated for their diuretic (by Lipschitz et al. method), antihypertensive activity by non-invasive blood pressure (NIBP) using the tail-cuff method and anti-diabetic potential in rats. Six compounds showing significantly excellent activity were compared with metolazone, prazosin and diazoxide as standards. Compound N-[7-chloro-2-(4-methoxyphenyl)-4-oxoquinazolin-3(4H)-yl]-4 nitrobenzenesulfonamide (20) exhibited most potent of the series.

Synthesis and antihypertensive screening of new derivatives of quinazolines linked with isoxazole.

A series of 7-substituted-3-(4-(3-(4-substitutedphenyl)-4,5-dihydroisoxazol-5-yl)phenyl)-2-substituted quinazolin-4(3H)-one (1-30) have been synthesized by the cyclization of (E)-3-(4-(3-substitutedphenyl)acrylolyl)phenyl)-2-(substitutedphenyl)-7-substituted quinazolin-4-(3H)-one with hydroxylamine hydrochloride. The synthesized compounds were examined for their in vivo antihypertensive activity using albino rats. All the titled compounds exhibited good to moderate antihypertensive activity. Compounds 7-Chloro-3-(4-(3-(4-chlorophenyl)-4,5- dihydroisoxazol-5-yl)phenyl)-2-p-tolylquinazolin-4(3H)-one (23) and 7-Chloro-3-(4-(3-(4-chlorophenyl)-4,5-dihydroisoxazol-5-yl)phenyl)-2-(4-methoxyphenyl)quinazolin-4(3H)-one (24) exhibited potent antihypertensive activity through their anticipated α 1-adrenergic receptor blocking property similar to its clinically used analogue, prazosin, without affecting heart rate with prolonged duration of action when tested in adrenaline induced hypertension in anaesthetized rats.