Synthesis and antidepressant activity of some 1,3,5-triphenyl-2-pyrazolines and 3-(2"-hydroxy naphthalen-1"-yl)-1,5-diphenyl-2-pyrazolines

Five new 1,3,5-triphenyl-2-pyrazolines were synthesised by reacting 1,3-diphenyl-2-propene-1-one with phenyl hydrazine hydrochloride and another five new 3-(2"-hydroxy naphthalen-1"-yl)-1,5-diphenyl-2-pyrazolines were synthesised by reacting 1-(2'-hydroxynaphthyl)-3- henyl-2-propene-1-one with phenyl hydrazine hydrochloride. The structures of the compounds were proved by means of their IR, H-1 NMR spectroscopic data, and microanalyses. The antidepressant activity of these compounds was evaluated by the 'Porsolt behavioural despairtest' on Swiss-Webster mice. 1-Phenyl-3-(2"-hydroxyphenyl)-5-(4'-dimethylaminophenyl)-2-pyrazoline, 5-(4'-dimethylaminophenyl)-1, 3-diphenyl-2-pyrazo line, 1-phenyl-3-(2"-hydroxynaphthalen-1"-yl)-5-(3',4',5'-trimethoxyphenyl)-2-pyrazoline, 1-phenyl-3-(4"-methylphenyl)-5-(4-dimethylaminophenyl)-2-pyrazoline and 1-phenyl-3-(4"-bromophenyl)-5-(4'dimethyl amino phenyl)-2-pyrazo line reduced immobility times 25.63-59.25% at 100 mg/kg dose level. In addition, it was found that the compounds possessing electron-releasing groups such as dimethyl amino, methoxy and hydroxyl substituents, on both the aromatic rings at positions 3 and 5 of pyrazolines, considerably enhanced the antidepressant activity when compared to the pyrazolines having no substituents on the phenyl rings. (c) 2005 Elsevier Ltd. All rights reserved.