Enantioselective cyanosilylation of aldehydes catalyzed by novel camphor derived Schiff bases-titanium(IV) complexes
作者:Ewelina Błocka、Mariusz J. Bosiak、Mirosław Wełniak、Agnieszka Ludwiczak、Andrzej Wojtczak
DOI:10.1016/j.tetasy.2014.03.001
日期:2014.4
Five tridentate Schiff bases have been prepared from (1R,2S,3R,4S)-3-amino-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol and salicylaldehydes. X-ray structure investigation revealed differences in their molecular conformation, and their titanium(IV) complexes have been studied with NMR techniques. Among them the complex with the Schiffbase obtained from 2-hydroxy-3-isopropylbenzaldehyde, is the most selective
Kinetic resolution of mandelate esters via stereoselective acylation catalyzed by lipase PS-30
作者:Peiran Chen、Wenhong Yang
DOI:10.1016/j.tetlet.2014.02.095
日期:2014.4
By using lipase PS-30 as catalyst, the kineticresolution of a series of racemic mandelate esters has been achieved via stereoselective acylation. The value of kinetic enantiomeric ratio (E) reached up to 197.5. Substituent effect is briefly discussed.
Chiral Solvating Agents for Cyanohydrins and Carboxylic Acids
作者:Lomary S. Moon、Mohan Pal、Yoganjaneyulu Kasetti、Prasad V. Bharatam、Ravinder S. Jolly
DOI:10.1021/jo100445d
日期:2010.8.20
as an ion pair of (R)- or (S)-mandelate and dimethylamminopyridinium ions possesses structural features that are sufficient for NMR enantiodiscrimination of cyanohydrins. Moreover, 1H NMR data of cyanohydrins of known configuration obtained in the presence of the mandelate−dimethylaminopyridinium ion pair point to the existence of a correlation between chemical shifts and absoluteconfiguration of cyanohydrins
我们已经表明,简单的结构如(R)-或(S)-扁桃酸盐和二甲基am基吡啶鎓离子对就具有足以对氰醇进行NMR对映异构的结构特征。此外,在扁桃酸-二甲基氨基吡啶鎓离子对存在下获得的已知构型的氰醇的1 H NMR数据表明,化学位移与氰醇的绝对构型之间存在相关性。扁桃酸酯-DMAPH +离子对和扁桃腈形成(1:1)配合物,(R)-扁桃腈/(R的缔合常数为338 M -1(ΔG 0,-3.4 kcal / mol))-扁桃酸酯-DMAPH +和(R)-扁桃腈/(S)-扁桃酸酯-DMAPH +络合物的139 M -1(ΔG 0,-2.9 kcal / mol)。为了理解enantiodiscrimination的起源,(三元配合物的模型的几何形状的优化和能量最小化小号)-mandelonitrile /([R )-扁桃酸盐/ DMAPH +和(小号)-mandelonitrile /(小号) -扁桃酸盐/
Nitrilases, nucleic acids encoding them and methods for making and using them
申请人:Diversa Corporation
公开号:US20040014195A1
公开(公告)日:2004-01-22
The invention relates to nitrilases and to nucleic acids encoding the nitrilases. In addition methods of designing new nitrilases and method of use thereof are also provided. The nitrilases have increased activity and stability at increased pH and temperature.
An Enzyme Library Approach to Biocatalysis: Development of Nitrilases for Enantioselective Production of Carboxylic Acid Derivatives
作者:Grace DeSantis、Zuolin Zhu、William A. Greenberg、Kelvin Wong、Jenny Chaplin、Sarah R. Hanson、Bob Farwell、Lawrence W. Nicholson、Cynthia L. Rand、David P. Weiner、Dan E. Robertson、Mark J. Burk
DOI:10.1021/ja0259842
日期:2002.8.1
and diverse set of nitrilases is reported. The utility of this nitrilaselibrary for identifying enzymes that catalyze efficient production of valuable hydroxy carboxylicacidderivatives is demonstrated. Unprecedented enantioselectivity and substrate scope are highlighted for three newly discovered and distinct nitrilases. For example, a wide array of (R)-mandelic acidderivatives and analogues were