Preparation of a HMG-CoA Reductase Inhibitor via an Optimized Imidazole-Forming Condensation Reaction
作者:Daniel M. Bowles、Gary L. Bolton、David C. Boyles、Timothy T. Curran、Richard H. Hutchings、Scott D. Larsen、Jonathan M. Miller、William K. C. Park、Kurtis G. Ritsema、David C. Schineman、Markus Tamm
DOI:10.1021/op800092e
日期:2008.11.21
Development work toward an enabling synthesis of preparative scale batches of an imidazole-based HMG-CoA reductase inhibitor is described. The desired target was synthesized in 16% yield over 7 steps, highlighted by an imidazole-forming condensation reaction in which the yield was improved from 20% to >70% via modification of the solvent, acid, and amine equivalents. The step 2 acylation was improved, and a problematic benzyl ester in step 4 was converted into the corresponding benzyl amide to decrease trans-amidation during the step 5 imidazole formation. A highly effective salt formation and crystallization protocol was also developed.