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Abstract: The synthesis and biological evaluation of novel pyrazole and imidazole carboxamides as CB1 antagonists are described. As a part of eastern amide SAR, various chemically diverse motifs were introduced on rimonabant template. The central pyrazole core was also replaced with its conformationally constrained motif and imidazole moieties. In general, a range of modifications were well tolerated. Several molecules with low- and sub-nanomolar potencies were identified as potent CB1 receptor antagonists. The in vivo proof of principle for weight loss is demonstrated with a lead compound in DIO mice model. [Copyright &y& Elsevier]

Abstract: The synthesis and biological evaluation of novel pyrazole-3-carboxamide derivatives as CB1 antagonists are described. As a part of eastern amide SAR, various chemically diverse motifs were introduced. In general, a range of modifications were well tolerated. Several molecules with high polar surface area were also indentified as potent CB1 receptor antagonists. The in vivo proof of principle for weight loss is exemplified with a lead compound from this series. [Copyright &y& Elsevier]

Abstract: A series of amides, amidines and amidoximes have been made from the corresponding nitrile compounds, to provide potent antagonists and inverse agonists for the CB1 receptor with considerably lower lipophiliciy, higher polar surface area and improved plasma/brain ratios compared to the centrally acting rimonabant. Extensive investigations of ADME and in vivo pharmacological properties led to selection of the amide series and specifically the 4-(4-fluorophenyl)piperidin-4-ol derivative D4. A clear improvement in the peripheral profile over rimonabant was seen, although some contribution of central effect on the pronounced weight reduction in obese mice cannot be ruled out. [Copyright &y& Elsevier]

Abstract: A chemically diverse library of secondary and tertiary 4-cyanomethyl-1,5-diphenyl-1H-pyrazole-3-carboxamides was synthesized to enable mapping of the SAR, in the eastern amide region, with regard to CB1 antagonist activity, This study was initiated as a prelude to the design and synthesis of possible CB1 antagonists that do not readily pass the blood–brain-barrier. In general a range of modifications were found to be tolerated in this part of the molecule, although polar and especially charged groups did to a degree reduce the CB1 antagonistic activity. Several compounds with single-digit or even sub-nanomolar potency, suitable for further elaboration of the nitrile moiety, were identified. [Copyright &y& Elsevier]

Abstract: Among cannabinoid type-1 (CB1) receptor antagonists, those developed around the 1,5-diarylpyrazole scaffold of rimonabant (Acomplia™) are the most extensively investigated. In recent years, many SAR and QSAR reports on this topic have been published, focusing on the substitution and orientation of the N1 and C5 aryl functionalities and on the substituents at the 3-carboxamide position. In this context, the purpose of our study was to design and synthesize a set of 1-(2,4-dichlorophenyl)-5-arylpyrazoles strictly related to rimonabant, but with the hydrazide/amide group shifted from position 3 to position 4 of the pyrazole scaffold. The synthesized compounds were evaluated in vitro for their affinity on human CB1 and CB2 (cannabinoid type-2) receptors. Computational studies, performed both in the design step and after biological assays, contributed to rationalize the obtained results in terms of specific molecular interactions between antagonists and the human CB1 receptor. [Copyright &y& Elsevier]