A new homostilbene and two new homoisoflavones from the bulbs of Scilla scilloides

A new homostilbene, named scillabene A (2), and two new homoisoflavones, named scillavones A (3) and B (4), were isolated from the bulbs of Scilla scilloides DRUCE (Liliaceae) along with 13 known compounds comprising a homostilbene, seven homoisoflavones, a xanthone, a lignan, and three nortriterpenes. The structures of 2-4 were characterized as 3,5,4'-trihydroxy-3'-methoxy-4-methyl-trans-stilbene, (3R)-5,7,2'-trihydroxy-3',4'-dimethoxyspiro{2H-1-benzopyran-7'-bicyclo[4,2,0]octa[1,3,5]-trien}-4-one and (3S)-3-(3,4-dihydroxybenzyl)-5-hydroxy-6,7-dimethoxychroman-4-one, respectively, on the basis of spectroscopic data and X-ray crystallographic analysis.     

Epoxidation of chalcones

Previously undescribed aromatic α-keto oxides have been obtained by the epoxidation of chalcones with alkaline hydrogen peroxide in methanolic solution.     

Epoxidation of chalcones

Previously undescribed aromatic -keto oxides have been obtained by the epoxidation of chalcones with alkaline hydrogen peroxide in methanolic solution.     

Epoxidation of Alkyllithium Polybutadienes

Epoxidations with peracetic acid were effected on a series of alkyllithium and sodium polybutadienes, and the properties of the epoxy resins were compared. The alkyllithium and sodium polybutadienes differed in micro-structure and molecular weight distribution. The alkyllithium polybutadienes were more readily epoxidized, and epoxidation resulted in dramatically lower viscosity increases with increasing epoxy contents. Epoxidized alkyllithium polybutadienes varying in molecular weight and epoxy content were shown to be compatible, efficient, and permanent plasticizer-stabilizers for polyvinyl chloride.     

烯烃的环氧化反应

介绍了几种不同氧源的烯烃环氧化反应 ,对其研究现状和发展趋势进行了简要的评述     

环氧环己烷的电化学合成

环氧环己烷的电化学合成何俊翔＊周锦成（温州师范学院化学系温州３２５００３）关键词电化学环氧化，环氧环己烷，环己烯，钛基氧化物电极１９９６－１１－２２收稿，１９９７－０６－０５修回间接电解氧化合成环氧化合物的研究已有报道［１～４］．它们均在铂电极上完成...     

Preparation and Epoxidation of Conjugated Lactams: Influence of Ring Size on Epoxidation

α,β-Epoxy-lactams can be prepared from conjugated lactams by treatment with m-chloroperoxybenzoic acid. Good yields are obtained, however, only with 2-pyrrolidinone derivatives. The yield of epoxy-lactam diminishes dramatically as the size of the lactam ring increases.     

Flavonol galactoside caffeiate ester and homoisoflavones from Caesalpinia millettii HOOK. et ARN

Chemical examination of the stems of Caesalpinia millettii HOOK. et ARN. led to the isolation of new flavonol glycoside caffeiate ester (1) and homoisoflavone (2), along with four known homoisoflavones: eucomin (3), bonducellin (4), 8-methoxybonducellin (5) and intricatinol (6). The structures of 1 and 2 were established to be tamarixetin 3-O-(6'-O-E-caffeoyl)-beta-D-galactopyranoside (1) and (Z)-7-hydroxy-8-methoxy-3-(4-methoxybenzyl) chroman-4-one (2) on the basis of detailed analyses of physical, chemical, and spectral data. Compounds 3-6 were isolated from this plant for the first time.     

Epoxidation of unsaturated carbonyl compounds

Russian Journal of Organic Chemistry - Epoxidation of unsaturated carbonyl compounds by reaction with chloromethyl propargyl(allyl) ether in the presence of an alcoholate occurs exclusively at the...     

环氧化反应的新进展

本文着重介绍各种环氧化剂的制法、性能、应用范围以及它们与烯烃作用的反应机理。对烯丙醇和不含官能团的烯烃的不对称环氧化反应也进行了详细的讨论。     

不对称催化环氧化反应

本文综述了不对称催化环氧化体系的研究进展。重点评述了Sharpless-Kat-suki不对称环氧化反应的特点、机理、新进展与应用,综合分析了由手性(salen)Mn(Ⅲ)催化剂对非功能化烯烃所创建的突出成果与应用前景。     

无催化剂条件下环辛烯环氧化反应

以O2气为氧源,在无溶剂无引发剂条件下,研究了非催化剂体系中环辛烯环氧化反应,并考察了反应温度、时间、压力、自由基引发剂以及自由基阻聚剂对环辛烯环氧化反应的影响. 实验结果表明,在无催化剂条件下,当反应初压0.60 MPa,反应时间2.0 h时,在140 ℃的较高温度下,以分子氧为氧源,环辛烯的转化率为44.5%,环氧环辛烷的选择性可达到64.4%.     

Epoxidation of 1,2-dihydroquinoline derivatives

The -oxide derivatives of 1,2-dihydroquinolines were synthesized and hydrated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 823–824, June, 1972.     

Epoxidation of alantolactone and isoalantolactone

Alantolactone and isoalantolactone have been epoxidized with peracetic, m-chloroperbenzoic, and trifluoroperacetic acids. The structure of 4(15)--epoxyisoalactone has been established by an x-ray structural investigation.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 879–884, November–December, 1996. Original article submitted May 20, 1996.     

Epoxidation of olefins by oxaziridines

The first examples of the epoxidation of olefins by oxaziridines, 2-benzenesulfonyl-3-aryloxaziridines ($\text{1a-b}$) is described.     

二氧杂环丙烷参与的烯烃环氧化反应

酮是催化烯烃环氧化反应的一类重要催化剂, 酮与氧化剂KHSO₅ (Oxone)可原位产生二氧杂环丙烷中间体, 然后二氧杂环丙烷中间体将氧原子传递给烯烃使之成为环氧化物, 而自身又生成原来的酮. 酮的催化效能大小与酮产生二氧杂环丙烷的能力、二氧杂环丙烷将氧原子传给烯烃的能力以及反应条件下酮的稳定性有关. 本工作对各种脂肪酮、脂环酮、杂环酮对烯烃环氧化催化能力的大小及其影响因素进行了评述.     

红花籽油的环氧化工艺

以双氧水为氧化剂,甲酸为氧载体,用强酸性阳离子交换树脂作催化剂,结合正交实验和单因素实验,确定红花籽油环氧化反应的最佳工艺条件为：在少量金属掩蔽剂乙二胺四乙酸二钠（EDTA）存在下,红花籽油、88%甲酸、30%双氧水和阳离子交换树脂的质量比为1∶0.244∶1.665∶0.035,在60 ℃下反应6 h,搅拌速度400 r/min,产品的环氧值可达到7以上。     

非官能化烯烃的不对称催化环氧化反应

手性环氧化合物是有机合成的重要中间体,由于三元杂环的张力使其很容易与各种亲核试剂作用,通过官能团转化反应,可以从环氧化物制备一系列不同结构的手性化合物.烯烃的不对称环氧化反应可以使潜手性的烯烃转化为带有手性碳的环氧化合物,在医药、农药、香料等精细化学品的合成上具有非常重要的意义.非官能化烯烃经手性催化剂诱导的不对称环氧化反应是获得光学纯手性化合物的有效方法.这些手性催化剂包括生物酶、金属卟啉、金属Salen配合物以及有机小分子催化剂.本文综述了这几种催化剂催化的非官能化烯烃不对称催化环氧化反应近几年的研究进展,介绍了催化剂的催化机理,并就其发展趋势提出了构想.     

多金属氧酸盐催化烯烃环氧化研究进展

综述了以过氧化氢为氧源,多金属氧酸盐催化烯烃环氧化的研究进展,尤其是针对基于多金属氧酸盐的反应控制相转移催化体系近年来的研究进展进行了详细阐述.