Chiral dioxomolybdenum(VI) complexes for enantioselective alkene epoxidation
摘要:
Chiral dioxomolybdenum(M) complexes of the type MoO2Cl2(L*) (L* = oxime), MoO2(THF)(2)L* (L* = cis-p-menthane-3,8-diol) and MoO2Cl(THF)L* (L* = 8-phenylthioneomenthol and 8-phenylthioisoneomenthol) have been prepared in good yields by reacting MoO2Cl2(THF)(2) with the appropriate chiral organic bidentate O,O-, O,N- and O,S-ligands. The complexes were characterised by solution NMR (H-1, C-13, Mo-95) and IR spectroscopy as well as elementary analysis, and were evaluated as catalysts in solution for the asymmetric epoxidation of cis-beta -methylstyrene by tert-butylhydroperoxide (TBHP). The cis-diol complex shows high catalytic activity and enantiomeric excesses of up to 25%. An attempt was made to immobilise the complex MoO2(THF)Cl[(-)-8-phenylthioneomenthol] within the channels of MCM-41 mesoporous silica by using a tethering ligand [L = NC(CH2)(3)Si(OEt)(3)]. The material was characterised by powder X-ray diffraction (XRD), IR spectroscopy and magic-angle-spinning (MAS) NMR (C-13, Si-29). Catalytic examinations demonstrated that it was active in the epoxidation of cyclooctene by TBHP. (C) 2001 Elsevier Science B.V. All rights reserved.
媒介传播疾病每年导致约 700,000 人死亡。驱虫剂是限制它们的策略之一。对薄荷烷-3,8-二醇 (PMD) 是一种天然化合物,是传统合成驱虫剂最有前途的替代品之一。这项工作描述了一种从对映体纯香茅醛合成 PMD 的每种非对映异构体的非对映发散方法,并研究了它们对白纹伊蚊的驱避活性。我们发现顺式-PMD是香茅醛环化的动力学控制产物,而反式-PMD是热力学控制产物。晶体的 X 射线衍射分析突出了顺式或反式之间氢键模式的一些差异异构体。本论文使用新的评估系统 24 小时证明 (1 R )-(+)- cis -PMD 具有最高的排斥指数。(1 S )-(-)- cis -PMD 略低,(1 S )-(+)- trans -PMD 和 (1 R )-(-)- trans -PMD 有轻微影响。志愿者测试表明 (1 R )-(+)- cis -PMD 是最有效的。这种效应可归因于 PMD/昆虫气味
The biotransformations of (RS)-linalool (1), (S)-citronellal (2), and sabinene (3) with fungi isolated from the epicarp of fruits of Citrus genus of the Amazonian forest (i.e., C. limon, C. aurantifolia, C. aurantium, and C. paradisiaca) are reported. The more active strains have been characterized, and they belong to the genus Penicillium and Fusarium. Different biotransformation products have been
Sustainable carbon acid catalysts exhibited high-performance in the conversion of citronellal to p-menthane-3,8-diol via a carbocation-hydration pathway.
P-MENTHANE-3,8-DIOL ISOMER MIXTURE, COOLING SENSATION COMPOSITION COMPRISING THE SAME, AND PRODUCT COMPRISING THE COOLING SENSATION COMPOSITION
申请人:Komatsuki Yasuhiro
公开号:US20140219931A1
公开(公告)日:2014-08-07
The present invention relates to a p-menthane-3,8-diol isomer mixture 50% by mass or more of which is constituted of (1S)-isomers and a cooling sensation composition containing this mixture. The present invention also relates to a flavor and/or fragrance composition, food, beverage, cosmetic, daily use product, oral cavity composition, or pharmaceutical containing the p-menthane-3,8-diol isomer mixture in an amount of 0.0001 to 90% by mass.
Three menthols, (+)- and(-)-neomenthols and(+)-isomenthol were biotransformed by Aspergillus niger which converted nonspecifically (-)- and (+)-neomenthols to mere hydroxylated compounds, whereas, (+)-isomenthol was smoothly converted into 1-hydroxyisomenthol and 6-hydroxyisomenthol by the same fungus.
Biotransformation of Citronellal by <i>Solanum </i><i>a</i><i>viculare</i> Suspension Cultures: Preparation of <i>p</i>-Menthane-3,8-diols and Determination of Their Absolute Configurations
Citronellal was transformed by Solanum aviculare suspension cultures to menthane-3,8-diols. cis-Menthane-3,8-diol dominated over the trans-isomer (39% and 15%, respectively). Absolute configurations of menthane-3,8-diols were assigned by critical analysis of H-1 and F-19 NMR spectra of prepared esters with 2-methoxy-2-phenyl-3,3,3-trifluoropropanoic acid. Citronellol and isopulegol were other products of the transformation (23% and 17%, respectively). The reaction course was identical for both citronellal enantiomers.