480421-63-4Relevant academic research and scientific papers
Structure-activity relationships of 1-alkyl-5-(3,4-dichlorophenyl)-5-{2-[(3-substituted)-1-azetidinyl]ethyl} -2-piperidones. 1. Selective antagonists of the neurokinin-2 receptor
MacKenzie, A. Roderick,Marchington, Allan P.,Middleton, Donald S.,Newman, Sandra D.,Jones, Barry C.
, p. 5365 - 5377 (2007/10/03)
The design, synthesis, and pharmacological evaluation of a novel class of neurokinin-2 (NK2) antagonists 1-alkyl-5-(3,4-dichlorophenyl)-5-{2-[(3-substituted)- 1-azetidinyl]ethyl}-2-piperidones (5-44) are described. These compounds are formally derived from 2 by incorporating the metabolically vulnerable N-methylamide function into a more stable six-membered ring lactam 4, resulting in increased stability in human liver microsome (HLM) preparations relative to 2 (T1/2(HLM) of 30 min vs 2 receptor in the Rabbit pulmonary artery (RPA) assay (pA2 = 9.3) and increased in vitro metabolic stability (T1/2(HLM) = 70 min) relative to 4. Metabolic route identification studies revealed that N-benzyl oxidation was a major route in this relatively lipophilic lead (log D = 3.2). Further exploration of the N-lactam substituent SAR targeting reduced lipophilicity to attenuate P-450 metabolism revealed that incorporation of a cyclopropylmethyl group in this region of the molecule gave a balance of good potency and high metabolic stability. For example, the significantly less lipophilic analogue 29 (log D = 2.3) possessed both good functional potency (RPA, pA2 = 8. 1) and high in vitro metabolic stability (T1/2(HLM) = 120 min). Optimization in this N-cyclopropylmethyllactam series by modification of the nature of the azetidine 3-substituent as a strategy to further increase potency and moderate log D led to the identification of sulfamide analogue 33, which possessed both excellent metabolic stability in vitro (T1/2(HLM) > 120 min) and high potency in both RPA (pA2 = 8.9) and human bladder smooth muscle (pKb = 8.9) functional assays. In addition, NK2 antagonist 33 (IC50 = 4 nM) showed excellent selectivity over both the related human neurokinin receptors h-NK1 (IC50 = 7.9 μM) and h-NK3 (IC50 = 1.8 μM) in radioligand binding studies.
