Substituted 2-Iminopiperidines as Inhibitors of Human Nitric Oxide Synthase Isoforms
摘要:
A series of analogues of 2-iminopiperidine have been prepared and shown to be potent inhibitors of the human nitric oxide synthase (NOS) isoforms. Methyl substitutions on the 4-position (3) or 4- and 6-positions (8) afforded the most potent analogues. These compounds exibited IC50 values of 0.1 and 0.08 mu M, respectively, for hiNOS inhibition. Substitution with cyclohexylmethyl at the 6-position (13) afforded an inhibitor that showed the best selectivity for hiNOS versus heNOS (heNOS IC50/hiNOS IC50 = 64). Following oral administration, inhibitors were found to decrease serum nitrite/nitrate levels in an in vivo rat endotoxin assay. This series of 2-iminopiperidines were prepared via the described synthetic methodologies. The effect of ring substitutions on potency and selectivity for this class of cyclic amidines as NOS inhibitors is described.
Catalytic Asymmetric Vinylation of Ketone Enolates
作者:André Chieffi、Ken Kamikawa、Jens Åhman、Joseph M. Fox、Stephen L. Buchwald
DOI:10.1021/ol0159470
日期:2001.6.1
[see reaction]. A protocol for the catalytic asymmetric vinylation of ketoneenolates has been developed. Key to the success of this process was the development of new electron-rich chiral monodentate ligands.
An Improved Catalyst for the Asymmetric Arylation of Ketone Enolates
作者:Takayuki Hamada、André Chieffi、Jens Åhman、Stephen L. Buchwald
DOI:10.1021/ja011122+
日期:2002.2.1
system for the enantioselective alpha-arylation of ketones is reported. This catalyst, prepared from Pd(2)(dba)(3) and a bulky dialkylphosphino-binaphthyl ligand, is able to effect the asymmetricarylation of ketoneenolates with aryl bromides utilizing NaO(t)()Bu as base. These new catalysts enjoy much higher reactivity than previous systems; arylation reactions could be effected at room temperature