4,5-Dihydro-1H-pyrazole/3,4-Diarylpyrazoline class of cannabinoid-1 (CB1R) receptor antagonists and their potential in medicinal applications

Various pharmacological agents mainly antagonists (inverse agonists) have been developed targeting the cannabinoid-1 (CB1) receptors of the endocannabinoid system. These agents that belong to diverse chemical scaffolds have potential in treating diabesity, mitigating metabolic dysfunctions, and ameliorating fibrosis. The prototypical CB1R antagonist (inverse agonist) Rimonabant (Acomplia/Zimulti) was developed as a first-in-class antiobesity medication. However, neuropsychiatric side effects led to the withdrawal of this drug and termination of many clinical programs based on CNS-penetrant CB1 antagonists/inverse agonists. Recent efforts have focused on developing CB1 antagonists that have negligible brain penetrance yet retaining many of the beneficial metabolic effects arising from CB1R blockade. Focus will be mainly on the medicinal chemistry approaches and the biological evaluation of the peripherally restricted, 4,5-dihydropyrazole (3,4-diarylpyrazoline)-based cannabinoid modulators.