Diverse Pathways for the Palladium(II)-Mediated Oxidation of Olefins by <i>tert</i>-Butylhydroperoxide
作者:Jin-Quan Yu、E. J. Corey
DOI:10.1021/ol0262340
日期:2002.8.1
[reaction: see text] New procedures are described for the palladium-catalyzed oxidation of olefins by tert-butylhydroperoxide under slightly basic conditions in CH(2)Cl(2) solution at 0-25 degrees C.
Epoxidation of strained alkenes catalysed by (1,2-dimethyl-4(1H)pyridinone-3-olate)2MnIIICl
作者:Adam P. Robinson-Miller、Mark F. Wyatt、David Tétard
DOI:10.1016/j.molcata.2014.12.012
日期:2015.3
The mild epoxidation of strained alkenes using (DMPO)2MnCl catalyst (DMPO = 1,2-dimethyl-4(1H)-pyridinone-3-olate) in the presence of various oxidants was studied. Hydrogenperoxide and monopersulfate were found to be the best oxidants when used with imidazole in acetonitrile at 4 °C, with up to 94% conversion. Dismutation of hydrogenperoxide was also observed when used as an oxidant. The epoxidation
研究了在各种氧化剂存在下,使用(DMPO)2 MnCl催化剂(DMPO = 1,2-二甲基-4(1H)-吡啶酮-3-油酸酯)对链烯烃进行的轻度环氧化。与咪唑一起在4°C的乙腈中使用时,发现过氧化氢和单过硫酸盐是最好的氧化剂,转化率高达94%。当用作氧化剂时,也观察到过氧化氢的歧化。使用过氧化氢或单过硫酸氢盐的环氧化似乎是温和的,并且对于过滤的烯烃具有非常高的选择性。提出了一种机制,其中需要咪唑来活化氧化剂,并提出了将检测到的Mn V = O物种作为活性物种。H 2 O 2之间的竞争反应 提出了用于活性物质的底物,并讨论了氧化剂的OO键的均裂与异裂。
Cycloaliphatic compounds, analgesic compositions thereof and method of
申请人:Glaxo Group Limited
公开号:US04291059A1
公开(公告)日:1981-09-22
Compounds are disclosed of general formula (I) ##STR1## in which R.sub.1 represents a hydrogen atom, a halogen atom or a group OR.sub.2, in which R.sub.2 represents a hydrogen atom, an alkyl group or an acyl group, R.sub.3 represents hydrogen or an alkyl, alkenyl or aryl group, R.sub.4 and R.sub.5 which may be the same or different, each represents a hydrogen atom or an alkyl, alkenyl or alkynyl group optionally substituted by an aryl or cycloalkyl group; or R.sub.4 and R.sub.5 together with the nitrogen atom may form a saturated four to seven membered ring, with the provisos that, when R.sub.4 and R.sub.5 simultaneously represent hydrogen atoms then (i) when R.sub.1 is hydrogen then R.sub.3 is not methyl and (ii) the compounds are the .beta.-isomers; and their physiologically acceptable salts. Compounds of formula (I) may be prepared from the corresponding .alpha.- or .beta.-configuration alcohols, from an aziridine intermediate or by a variety of alkylation procedures whereby the group R.sub.4 and/or R.sub.5 is introduced. The compounds (I) and their salts have analgesic activity and may be formulated as pharmaceutical compositions in conventional manner.
Exploiting Hydroxamic Acids as Organocatalysts for the Epoxidation of Alkenes with Hydrogen Peroxide as the Oxidant
作者:Efthymios T. Poursaitidis、Foteini Trigka、Christiana Mantzourani、Maroula G. Kokotou、Ierasia Triandafillidi、Christoforos G. Kokotos
DOI:10.1002/ejoc.202400082
日期:2024.4.2
An organocatalytic epoxidation of alkenes synthesis is presented in which hydroxamic acids are used as the catalyst and hydrogenperoxide as the green oxidant. Mechanistic studies by direct infusion HRMS provide experimental evidence for the formation of various intermediates.
Recyclable Polyurea-Microencapsulated Pd(0) Nanoparticles: An Efficient Catalyst for Hydrogenolysis of Epoxides
作者:Steven V. Ley、Claire Mitchell、David Pears、Chandrashekar Ramarao、Jin-Quan Yu、Wuzong Zhou
DOI:10.1021/ol0358509
日期:2003.11.1
Pd nanoparticles (similar to2 nm in size) microencapsulated in polyurea is an efficient and recyclable catalyst for reductive ring-opening hydrogenolysis of epoxides, using either HCOOH/Et3N or H-2 as a hydrogen donor.