Microstructure Analysis of Poly(cyclopentene carbonate)s at the Diad Level
摘要:
The spectroscopic assignment of poly(cyclopentene carbonate)s at the diad level was performed by using two kinds of model compounds: isotactic and syndiotactic dimers of cyclopentene carbonate unit. By comparing the signals in the carbonyl region, we concluded that the signals at 153.85 and 153.78 ppm in the C-13 NMR spectrum of poly(cydopentene carbonate) were attributed to m-diad and r-diad, respectively. The signals at 82.61 and 82.53 ppm in the C-13 NMR spectrum were assigned to m-diad and r-diad peak of methine resonance, respectively. It was found that the carbonate carbon signals were sensitive toward the stereocenters on adjacent epoxide ring-opening units. The syndiotactic and isotactic diads matched well with the microstructures of the stereoregular poly(cydopentene carbonate)s that were prepared by using chiral dinuclear Co(III) complex catalysts.
Chiral synthesis via organoboranes. 45. Asymmetric hydroboration of 1-cyclopentenol derivatives using diisopinocampheylborane. Synthesis of optically active cyclopentane-1,2-diol derivatives of high optical purity
作者:Herbert C. Brown、Dhanabalan Murali、Bakthan Singaram
DOI:10.1016/s0022-328x(99)00047-9
日期:1999.6
The asymmetric hydroboration of 1-cyclopentenol derivatives, such as ethers, acetate, silyl ether and borinate, was investigated using diisopinocampheylborane, dIpc2BH. The product trialkylboranes were treated with excess of acetaldehyde to give the corresponding diethyl boronate esters. These boronate esters on oxidation using alkaline hydrogen peroxide gave optically active trans-cyclopentane-1,2-diol
A method for the purification of alcohols from organic soluble impurities has been discovered comprising treating the crude alcohol with a cyclic anhydride followed by an aqueous base and extracting the corresponding half-ester into aqueous solution leaving the impurities in organic solution. This method is particularly useful for the separation of chiral, nonracemic alcohols from the corresponding antipodal ester (the mixture resulting from an enzymatic kinetic resolution) because the separation is non-chromatographic and the enantiomeric integrity of the products is maintained.
[EN] NOVEL COMPOUNDS FOR CONTROLLING ARTHROPODS<br/>[FR] NOUVEAUX COMPOSÉS POUR LUTTER CONTRE LES ARTHROPODES
申请人:BAYER ANIMAL HEALTH GMBH
公开号:WO2020007704A1
公开(公告)日:2020-01-09
The present invention relates to novel halogen-substituted compounds, to processes for their preparation and to their use for controlling animal pests, in particular arthropods and especially insects and arachnids.
A broadly applicable and practical oligomeric (salen)Co catalyst for enantioselective epoxide ring-opening reactions
作者:David E. White、Pamela M. Tadross、Zhe Lu、Eric N. Jacobsen
DOI:10.1016/j.tet.2014.03.043
日期:2014.7
enhancements in reactivity and enantioselectivity relative to monomeric and other multimeric (salen) Co catalysts in a wide variety of enantioselective epoxide ring-opening reactions. The application of catalyst 4a is illustrated in the kinetic resolution of terminalepoxides by nucleophilic ring-opening with water, phenols, and primary alcohols; the desymmetrization of meso epoxides by addition of
[EN] PYRIMIDINE SULPHONAMIDE DERIVATIVES AS CHEMOKINE RECEPTOR MODULATORS<br/>[FR] COMPOSES
申请人:ASTRAZENECA AB
公开号:WO2006024823A1
公开(公告)日:2006-03-09
A compound of formula (1), or a pharmaceutically acceptable salt, solvate or in vivo hydrolysable ester thereof and pharmaceutical compositions comprising these, all for use in the treatment of chemokine mediated diseases and disorders.