ReacTiO2ns for rings: Goldnanoparticles supported on TiO2 are used as a novel heterogeneous catalyst for the isomerization of epoxides to allylicalcohols by a concerted mechanism (see scheme). The reaction proceeds in high yields and the product selectivity is often remarkable.
Structure–Odor Activity Studies on Monoterpenoid Mercaptans Synthesized by Changing the Structural Motifs of the Key Food Odorant 1-<i>p</i>-Menthene-8-thiol
作者:Sebastian Schoenauer、Peter Schieberle
DOI:10.1021/acs.jafc.6b01645
日期:2016.5.18
ring always resulted in higher odor thresholds compared to thiols with a mercapto group in the side chains. Although all tertiary thiols always exhibited low odor thresholds, none of the 31 compounds reached the extremely low threshold of 1. Also, none of the synthesized mercapto monoterpenoids showed a similar odor quality resembling grapefruit. Although the saturated and aromatic analogues exhibited
1- p-甲基-Nenthene-8-硫醇(1)几十年前被发现是柚子汁中的主要气味物质,它对水果的整体气味有贡献,在空气中的气味阈值极低,仅为0.000034 ng / L。该值是有史以来针对食品气味剂报告的最低气味阈值之一。为了检查结构1的修饰是否会导致气味阈值和气味质量的变化,使用了34个含巯基的对薄荷烷和1- p合成了薄荷烯衍生物以及几种芳族和开链巯基单萜。文献中首次报道了其中的18种,并提供了它们的气味阈值和气味质量以及分析数据。感官数据与1的感官数据比较表明,双键的氢化导致气味阈值明显增加。此外,与在侧链中具有巯基的硫醇相比,将巯基移入环中总是导致较高的气味阈值。尽管所有叔硫醇始终表现出较低的气味阈值,但31种化合物均未达到极低的阈值1。同样,没有合成的巯基单萜类化合物具有类似于葡萄柚的类似气味质量。尽管饱和和芳香族类似物的香气与1类似,但大多数其他化合物的香气被描述为含硫,橡胶
Reactions of oxiranes with alkali metals: intermediacy of radical-anions
Reaction of oxiranes with alkali metals in aprotic solvents yields a variety of products depending on the nature of the metal and the structure of the oxirane. Deoxygenation to olefins is the major reaction in case of lithium. Rearrangement to carbonyl compounds, reduction to alcohols and formation of dimeric products occur when oxiranes are treated with sodium. All the reactions could be rationalised
Preparation of 2-exo-Hydroxy-7-oxabicyclo[2.2.1]heptanes
申请人:Shell Oil Company
公开号:US04487945A1
公开(公告)日:1984-12-11
2-exo-Hydroxy-7-oxabicyclo[2.2.1]heptanes are prepared by treating the corresponding cis-epoxycyclohexanol with acid in an inert solvent or by treating a 3-cyclohexen-1-ol which will produce the corresponding cis-epoxy alcohol successively or concurrently with an oxidizing agent and an acid in an inert solvent.
Spectroscopic, calorimetric, and catalytic evidences of hydrophobicity on Ti-MCM-41 silylated materials for olefin epoxidations
作者:Joaquín Silvestre-Alberó、Marcelo E. Domine、José L. Jordá、María T. Navarro、Fernando Rey、Francisco Rodríguez-Reinoso、Avelino Corma
DOI:10.1016/j.apcata.2015.09.029
日期:2015.10
the catalytic process. Thus, catalyst deactivation by glycol poisoning of Ti active sites is greatly diminished, this increasing catalyst stability and leading to practically quantitative production of the corresponding epoxide. The extended use of these hydrophobic Ti-MCM-41 catalysts together with organic hydroperoxides for the highly efficient and selective epoxidation of natural terpenes is also