Kinetic Resolution of cis-3-Alkylcyclohexene Oxide by a Chiral Lithium Amide - An Application to a Synthesis of Both Enantiomers of Isomenthon -
摘要:
Kinetic resolution of cis-3-alkylcyclohexene oxide (1) was examined using chiral lithium amide, lithium (S)-2-(pyrrolidin-1-yl)methylpyrrolidide (2). High cc (84-->98% eel of 1 was obtained by using 1.1-1.2 equiv of 2, while 6-alkyl-2-cyclohexenol (3) was obtained in moderate ee (60-68% eel by using 0.5-0.75 equiv of 2. Both enantiomers of cis-2-isopropyl-5-methylcyclohexanone (isomenthone)were derived from (1S,2R,3R)-(+)-3-isopropylcyclohexene oxide (1b) or (1R,6R)-(-)-6-isopropyl-2-cyclohexenol (3b) in a few steps, respectively.
Titanium-Catalyzed Heterogeneous Oxidations of Silanes, Chiral Allylic Alcohols, 3-Alkylcyclohexanes, and Thianthrene 5-Oxide: A Comparison of the Reactivities and Selectivities for the Large-Pore Zeolite Ti-β, the Mesoporous Ti-MCM-41, and the Layered Alumosilicate Ti-ITQ-2
A comparative study of silaneoxidation, olefin epoxidation, and thianthrene5-oxide sulfoxidation with the oxidants Ti-β/H2O2, Ti-MCM-41/t-BuOOH, and Ti-ITQ-2/t-BuOOH provides the catalytic reactivity order Ti-β>Ti-MCM-41>Ti-ITQ-2. The steric constraints of the narrow channels make the Ti-βzeolite the most selective. For the more open structures of the Ti-MCM-41 and Ti-ITQ-2 hosts, such steric constraints
用氧化剂Ti-β/ H 2 O 2,Ti-MCM-41 / t -BuOOH和Ti-ITQ-2 / t -BuOOH对硅烷氧化,烯烃环氧化和噻吨5氧化物硫氧化的比较研究提供了催化反应顺序为Ti-β> Ti-MCM-41> Ti-ITQ-2。狭窄通道的空间限制使Ti-β沸石具有最高的选择性。对于Ti-MCM-41和Ti-ITQ-2主体的更开放的结构,这种空间约束不太明显,因此,这些多相催化剂显示出较低的选择性。两者均通过类似于均相Ti(O i -Pr)4 / t的过渡结构激活t -BuOOH进行氧转移-BuOOH氧化剂。
Kinetic resolution of racemic epoxides using a chiral diamine catalyst
作者:Arnaud Gayet、Pher G. Andersson
DOI:10.1016/j.tetlet.2005.05.017
日期:2005.7
The kinetic resolution of a variety of racemic epoxides has been performed using a chiral bicyclic diamine ligand. Using 5 mol% of catalyst very high selectivity could be achieved; both epoxide and the corresponding allylic alcohol could be obtained in up to 99% ee. (c) 2005 Elsevier Ltd. All rights reserved.
ANTI-MICROBIAL AGENTS AND USES THEREOF
申请人:Tan Derek Shieh
公开号:US20090170805A1
公开(公告)日:2009-07-02
Many pathogens, including
Mycobacterium tuberculosis
and
Yersinia pestis
, rely on an iron acquisition system based on siderophores, secreted iron-chelating compounds with extremely high Fe(III) affinity. The compounds of the invention are inhibitors of domain salicylation enzymes, which catalyze the salicylation of an aroyl carrier protein (ArCP) domain to form a salicyl-ArCP domain thioester intermediate via a two-step reaction. The compounds include the intermediate mimic 5′-O—[N-(salicyl)sulfamoyl]-adenosine (salicyl-AMS) and analogs thereof. These compounds are inhibitors of the salicylate activity of MbtA, YbtE, PchD, and other domain salicylation enzymes involved in the biosynthesis of siderophores. Therefore, these compounds may be used in the treatment of infection caused by microorganisms which rely on siderphore-based iron acquisition systems. Pharmaceutical composition and methods of using these compounds to treat or prevent infection are also provided as well as methods of preparing the inventive compounds.