Synthesis, preclinical evaluation and antidepressant activity of 5-substituted phenyl-3-(thiophen-2-yl)-4, 5-dihydro-1H-pyrazole-1-carbothioamides

Abstract

A series of phenyl-3-(thiophen-2-yl)-4, 5-dihydro-1H-pyrazole-1-carbothioamides (TTa-TTg) were synthesized by the ring closure reaction of phenyl-1-(thiophen-2-yl) prop-2-en-1-ones with thiosemicarbazide in alcoholic basic medium. All the final derivatives were evaluated for their antidepressant and neurotoxicity screening. The structures of the compounds were characterized by IR, 1H NMR, 13C NMR, Mass and elemental analyses. Preclinical evaluation of the compounds were ascertained by in silico toxicity, blood-brain barrier and human oral absorption prediction. In this series, 5-(4-hydroxyphenyl)-3-(thiophen- 2-yl)-4,5-dihydro-1H-pyrazole-1 carbothioamide (TTg) reduced immobility time 61.17 and 62.05 % in both force swimming and tail suspension test respectively at 10 mg/kg dose level when compared to the standard Imipramine without influencing the baseline locomotion. Moreover it was observed that the titled scaffold possessing electron withdrawing chlorine atom in the 4th position of aromatic ring of the scaffold also showed good the antidepressant activity. In conclusion, the behavioural investigation revealed that thiophene based pyrazolines having a carbothioamide tail unit in the N1 position may be therapeutically useful as potential antidepressant medications.