[EN] PROCESS FOR PREPARING AN ANTI-HYPERCHOLESTEROLEMIC COMPOUND<br/>[FR] PROCÉDÉ DE PRÉPARATION D'UN COMPOSÉ ANTI-HYPERCHOLESTÉROLÉMIANT
申请人:MERCK & CO INC
公开号:WO2009054887A1
公开(公告)日:2009-04-30
The present invention relates to a process for preparing inhibitors of cholesterol absorption of Formula II: II and the pharmaceutically acceptable salts and esters thereof, employing a metal-catalyzed dynamic kinetic resolution (DKR) asymmetric transfer hydrogenation (ATH) reaction of racemic acyclic ß-ketoamide bearing a-substituted aliphatic side chain (Intermediate A) and subsequent cyclization of the resulting b-hydroxyamide product (Intermediate B), followed by a synthesis involving two consecutive cross-coupling reactions.
At elevated temperatures, N-cyanosulfoximines react with Meldrum’s acidderivatives to give sulfoximines with N-bound 5-carbonyl-1,3-oxazine-2,4-dione groups. A representative product was characterized by single-crystal X-ray structure analysis. The product formation involves an unexpected molecular reorientation requiring several sequential bond-forming and -cleaving processes.
Dynamic Kinetic Resolution: Asymmetric Transfer Hydrogenation of α-Alkyl-Substituted β-Ketoamides
作者:John Limanto、Shane W. Krska、Benjamin T. Dorner、Enrique Vazquez、Naoki Yoshikawa、Lushi Tan
DOI:10.1021/ol902715d
日期:2010.2.5
Dynamic kinetic resolution (deracemization) of various alpha-alkyl-substituted beta-ketoamides 1 via asymmetric transfer hydrogenation proceeded efficiently to give the corresponding syn-beta-hydroxy amides 3 in high diastereo- and enantioselectivities. Specifically, subjection of 1 to HCO2H and Et3N in the presence of 0.5-1 mol % of pentafluorobenzenesulfonyl-DPEN-Ru catalyst 2b at 30-40 degrees C in either PhCH3 or CH2Cl2 generated the syn-hydroxy product 3 selectively in 15-33:1 dr, 93-97% ee, and 75-88% isolated yields.