US EPA

1567466 

Journal Article 

Synthesis and Biological Evaluation of 2-(N-substituted)-3H-phthalazin-1, 4-diones and 1-(N- substituted) 2, 4, 5-trihydropyridazin-3, 6-diones as Potent Vasodilators 

Shreenivas, DR; Anant, GM; Vasantakumar, P 

2010 

1 

Indian Journal of Pharmaceutical Education & Research
ISSN: 0019-5464 

ASSOC PHARMACEUTICAL TEACHERS INDIA 

BANGALORE 

44 

1 

1-7 

WOS:000276050300001 

In view of increasing incidents of cardiovascular
complications and the subsequent urgent need in the development of therapeutic agents, 2-(N-
substituted)-3H-phthalazin-1,4-diones(3a-d) and 1-(N- substituted) 2,4,5-trihydropyridazin-3,6-
diones(4a-d) have been synthesized and characterized by spectral data. The title compounds were
prepared by condensing substituted aryl hydrazides with either phthalic anhydride or succinic
anhydride. The synthesized compounds have been screened for coronary vasodilator activity on the
isolated rat heart at 10 mu g concentration. Almost all the compounds have exhibited significant
activity. The in vitro nitric oxide donor activity by Griess reagent has been studied to
understand mechanism of action of these compounds. The compounds released nitric oxide
significantly at 100 mu mol, indicating the coronary vasodilatation produced by these compounds
could be at least, partially due to release of nitric oxide. 

phthalazines; pyridazines; antihypertensive; vasodilator; nitric oxide; Griess reagent