Efficient Chemoenzymatic Dynamic Kinetic Resolution of 1-Heteroaryl Ethanols
摘要:
The scope and limitation of the combined rutheinum-lipase induced dynamic kinetic resolution (DKR) through O-acetylation of racemic heteroaromatic secondary alcohols, i.e., 1-heteroaryl substituted ethanols, was investigated. After initial screening of reaction conditions, Candida antarctica lipase B (Novozyme 435, N435) together with 4-chloro-phenylacetate as acetyl-donor for kinetic resolution (KR), in conjunction with the ruthenium-based Shvo catalyst for substrate racemization in toluene at 80 degrees C, enabled DKR with high yields and stereoselectivity of various 1-heteroaryl ethanols, Such as oxadiazoles, isoxazoles, 1H-pyrazole, or 1H-imidazole. In addition, DFT calculations based on a simplified catalyst complex model for the catalytic (de)hydrogenation step are in agreement with the previously reported outer sphere mechanism. These results support the further understanding of the mechanistic aspects behind the difference in reactivity of 1-heteroaryl substituted ethanols in comparison to reference substrates, as often referred to in the literature.
5-SUBSTITUTED TETRALONES AS INHIBITORS OF RAS FARNESYL TRANSFERASE
申请人:WARNER-LAMBERT COMPANY
公开号:EP1276725A2
公开(公告)日:2003-01-22
[EN] 5-SUBSTITUTED TETRALONES AS INHIBITORS OF RAS FARNESYL TRANSFERASE<br/>[FR] TETRALONES 5-SUBSTITUEES EN TANT QU'INHIBITEURS DE RAS FARNESYL TRANSFERASE
申请人:WARNER LAMBERT CO
公开号:WO2001079180A2
公开(公告)日:2001-10-25
The present invention provides novel 5-substituted tetralones of Formulas (I), (II), (III) and (IV) and pharmaceutically acceptable salts, esters, amides, and prodrugs thereof, which are useful for treating and preventing uncontrolled or abnormal proliferation of tissues, such as cancer, atherosclerosis, restenosis, and psoriasis. Specifically, the present invention relates to compounds that inhibit the farnesyl transferase enzyme.
Efficient Chemoenzymatic Dynamic Kinetic Resolution of 1-Heteroaryl Ethanols
作者:Karl S. A. Vallin、David Wensbo Posaric、Zdenko Hameršak、Mats A. Svensson、Alexander B. E. Minidis
DOI:10.1021/jo901987z
日期:2009.12.18
The scope and limitation of the combined rutheinum-lipase induced dynamic kinetic resolution (DKR) through O-acetylation of racemic heteroaromatic secondary alcohols, i.e., 1-heteroaryl substituted ethanols, was investigated. After initial screening of reaction conditions, Candida antarctica lipase B (Novozyme 435, N435) together with 4-chloro-phenylacetate as acetyl-donor for kinetic resolution (KR), in conjunction with the ruthenium-based Shvo catalyst for substrate racemization in toluene at 80 degrees C, enabled DKR with high yields and stereoselectivity of various 1-heteroaryl ethanols, Such as oxadiazoles, isoxazoles, 1H-pyrazole, or 1H-imidazole. In addition, DFT calculations based on a simplified catalyst complex model for the catalytic (de)hydrogenation step are in agreement with the previously reported outer sphere mechanism. These results support the further understanding of the mechanistic aspects behind the difference in reactivity of 1-heteroaryl substituted ethanols in comparison to reference substrates, as often referred to in the literature.