Synthesis, antihypertensive activity, and 3D-QSAR studies of some new p-hydroxybenzohydrazide derivatives.

p-Hydroxybenzohydrazide 2 on treatment with aromatic/aliphatic aldehyde followed by cyclization with carbon disulphide afforded compounds 4a-4n. Also, compound 2 by treatment of substituted isothiocyanate followed by the treatment of chloroacetic acid yields the corresponding compounds 6a-6i. All the test compounds were assayed for antihypertensive activity by non-invasive blood pressure measurement and invasive blood pressure measurement methods. The test compounds showed significant antihypertensive activity. The intact compounds were subjected to 3D-QSAR studies. The 3D-QSAR analysis was carried out by PHASE program and a statistically reliable model with good predictive power (r(2)  = 0.98, q(2)  = 0.74) was achieved. The 3D-QSAR plots illustrated insights into the structure-activity relationship of these compounds which may aid in the design of potent p-hydroxybenzohydrazide derivatives as antihypertensive agents.