Synthesis and Antidepressant Activity of Some 3-(3''-Coumarinyl)-1,5-diphenyl-2-pyrazolines and 3-(2''- hydroxy naphthalen-1''-yl)-1,5-diphenyl-2-pyrazolines

Abstract

Five new 3-(3''-coumarinyl)-1,5-diphenyl-2-pyrazolines (3_a-e) were synthesised by reacting 3-[1-oxo-3-(substituted phenyl)-2-propenyl]-2H-1-benzopyran-2-ones (2_a-e) with phenyl hydrazine hydrochloride and another five new 3-(2''-hydroxy naphthalen-1''-yl)-1,5-diphenyl-2-pyrazolines (5_a-e) were synthesized by reacting 1-(2'-hydroxynaphthyl)-3-phenyl-2-propene-1-one (4_a-e) with phenyl hydrazine hydrochloride. All these compounds were characterized by means of their IR, ¹H NMR spectroscopic data and microanalyses. The antidepressant activity of these compounds was evaluated by the Porsolt behavioural despair test on Swiss-Webster mice. 3-(3''-coumarinyl)-1-phenyl-5-(2',4',5'-trimethylphenyl)-2-pyrazoline (3_a), 3-(3''-coumarinyl)-1-phenyl-5-(4'-hydroxy-3'-methoxyphenyl)-2-pyrazoline (3_d), 1-phenyl-3-(2''-hydroxynaphthalen-1''-yl)-5-(2',4',5'-trimethoxyphenyl)-2-pyrazoline (5_c) and 1-phenyl-3-(2''-hydroxynaphthalen-1''-yl)-5-(4'-dimethylaminophenyl)-2-pyrazoline (5_a) reduced 36.59-59.65 % immobility times at 100 mg kg^-1 dose level. It was observed that some of the 2-pyrazolines derived from 3-acetyl coumarin showed grater activity than those derived from 2-hydroxy-1-acetonaphthone. In addition it was found that the compounds possessing electron releasing groups such as dimethyl amino, methoxy and hydroxyl substituent, on both the rings at position 3 and 5 of pyrazolines, considerably enhanced the antidepressant activity when compared to the pyrazolines having no substituents on the rings.