Laboratory Evolution of Robust and Enantioselective Baeyer−Villiger Monooxygenases for Asymmetric Catalysis
作者:Manfred T. Reetz、Sheng Wu
DOI:10.1021/ja906212k
日期:2009.10.28
and induced fit docking suggests potential randomization sites, different from all previous approaches to focused library generation. Sites harboring highly conserved proline in a loop of the WT are targeted. The most active and enantioselective mutants retain the high thermostability of the parent WT PAMO. The success of the "proline" hypothesis in the present system calls for further testing in future
Polyamide fibers having reduced amino end groups, light-dyed and stain resistant polyamide fibers made therefrom, and method of preparation
申请人:BASF Corporation
公开号:EP0409093A2
公开(公告)日:1991-01-23
Polyamide fibers reacted with an epsilon-caprolactone compound have a reduced affinity for acid dyes. The fiber finds particular application in preparing two-tone yarn. Additionally, the polyamide fibers can be treated with one or more stainblockers to produce a stain resistant polyamide fiber having excellent resistance to acid dye colorants.
DBU-Catalyzed Deconjugation of 7-Substituted 3,4-Didehydro-2-oxepanones. Deuterium Incorporation, Significance of the Imine Double Bond, and Application to the Synthesis of a Key Pharmacophore
作者:Duraiswamy A. Jeyaraj、Kamal K. Kapoor、Veejendra K. Yadav、Harsh M. Gauniyal、Masood Parvez
DOI:10.1021/jo971417z
日期:1998.1.1
7-Substituted 3,4-Didehydro-2-oxepanones are conveniently deconjugated to the 4,5-didehydro derivatives by DBU. The isomerization of 7-benzyl-substituted 2-oxepanones proceeds to the extent of 90% over the initial 3 h; the concentration falls gradually thereafter to achieve, in 25 h, a 3:2 equilibrium in favor of deconjugation. Such an equilibrium does not exist for the 7-methyl and the 7-(2-phenethyl) derivatives. The significance of the imine double bond in DBU has been explored. The isomerization in CDCl3 causes deuterium incorporation at positions 3 and 5 of the 2-oxepanones examined and at position 6 of DBU. The mechanistic rationales for these deuterium incorporations are advanced. The transformation of 7-benzyl-3,4-didehydro-2-oxepanone into a bicyclo[3.3.0] skeleton that is present in a diverse class of biologically active natural products is described as a possible potential use of the present deconjugation methodology.
Free-Radical Ring Contraction of Six-, Seven-, and Eight-Membered Lactones by a 1,2-Shift Mechanism. A Kinetic and <sup>17</sup>O NMR Spectroscopic Study
作者:David Crich、Xiaohua Huang、Athelstan L. J. Beckwith
DOI:10.1021/jo982385y
日期:1999.3.1
Acid-dye resistant polyamide products and process for preparation