共查询到20条相似文献,搜索用时 140 毫秒
1.
3-甲基-2-丁烯酸乙酯4经SeO2反式氧化,还原,溴化得到关键中间体4-溴-3-甲基-(2E)-丁烯酸乙酯7.7与三苯基胂反应生成季Seng盐8。二氢香茅醛与8在K2CO3-乙醇-微量水的存在下反应,得到(2E,4E)-3,7,11-三甲基-2,4-十二碳二烯酸乙酯1a及其(2Z,4E)-异构体1b,产率74%,该反应具有(4E)-立体选择性,同时C-2双键发生部分构型转化。 相似文献
2.
3.
4-羟基-2,5-二甲基-3(2H)呋喃酮的合成 总被引:3,自引:0,他引:3
总结了食品增香剂4-羟基-2.5-二甲基-3(2H)呋喃国的合成方法,包括近期的合成研究进展,对一些合成方法的优缺点作了评述。参考文献28篇。 相似文献
4.
合成了23个新的1-(取代吡唑-4-基)1,2,4-三唑化合物,经EA、IR、~1HNMR和MS确定其组成和结构,并对其进行了抑菌及生长调节活性的初步观察。 相似文献
5.
先合成1,2,4-三嗪环,然后并接吡唑环,对标题化合物进行了合成研究。对1,2,4-三嗪环上的硫化反应进行了改进,解决了3个反应活性相近部位的选择性肼解问题;并发现了肼基与乙酸乙酯于室温下反应生成1,3,4- 二唑环的新反应。 相似文献
6.
1,2,4-三嗪类化合物的研究(ⅩⅫ)──咪唑并-(5,4-e)-1,2,4-三嗪衍生物的合成沙耀武,蔡孟深(北京医科大学药学院,北京,100083)关键词乙二脒腙,原甲酸三乙酯,1,2,4-三嗪,咪唑并-(5,4-e)-1,2,4-三嗪天然碱基拮抗... 相似文献
7.
合成了15个新的1-(取代异噁唑基)-1,2,4-三唑和1-(取代嘧啶基)-1,2,4-三唑化合物,经元素分析、IR、1HNMR和MS证实其结构,并对其代表化合物进行了抑菌及植物生长调节活性的初步观察 相似文献
8.
(2E,4E)-共轭双烯是许多天然产物的结构组分[1-5],由于几何异构体的分离及提纯较困难,因此合成高几何纯度的(2E,4E)共轭双烯衍生物是一个值得探讨的课题.Trost等[1]曾报道了利用α,β-炔酮及炔胺的异构化反应合成(2E,4E)-共轭双烯衍生物的方法. 相似文献
9.
3-芳基-4-氨基-1,2,4-均三唑-5-硫酮和2.4-二氯苯氧乙酰异硫氰酸酯在丙酮中于60℃回流,制得10个新的均三唑并[3,4-b]-1,3,4-噻二唑(3a-j)化合物,用元素分析、IR、1HNMR和MS确证了结构,并讨论了反应机制。 相似文献
10.
(R)-N-(γ-烃基-δ-酮己酰基)四氢噻唑-2-硫酮-4-羧酸乙酯的合成及其同(R,S)-α-苯乙胺的反应 总被引:1,自引:0,他引:1
γ-甲基-δ-酮己酸,γ-异丙基-δ-酮己酸在碘化N-甲基-2-氯吡啶盐存在下分别同(R)-四氢噻唑-2-硫酮-4-羧酸乙酯反应,得到光学活性的(R)-N-(γ-甲基-δ-酮己酰基)四氢噻唑-2-硫酮-4-羧酸乙酯(1a)及光学活性的(R)-N-(γ-异丙基-δ-酮己酰基)四氢噻唑-2-硫酮-4-羧酸乙酯(1b)。1a,1b分别同(R,S)-α-苯乙胺反应得到光学活性的酰胺2a,2b,同时使(R,S)-α-苯乙胺拆分,得到光学活性的α-苯乙胺。 相似文献
11.
CAO Long ;ZHOU Xiaohong ;CHEN Jie ;ZHANG Hui ;DENG Hongmei ;SHAO Min ;McMILLS Mark C. ;CAO Weiguo 《高等学校化学研究》2014,30(4):596-600
Trans-2,3-dihydrofuran derivatives 3 or 4 substituted with a sulfonyl group were prepared with high chemoselectivity and good yields by [1+4]-addition reaction of α,β-unsaturated ketones 1 with arsonium bromide 2 in CH2Cl2 in the presence of potassium carbonate at room temperature.The structures of the products were characterized by IR,MS,^1H NMR,elemental analysis and single crystal X-ray diffraction analysis.A mechanism for the formation of products was also proposed. 相似文献
12.
Reaction of dibutyl(alkylcarbamoylmethyl) tellurium halides with aldehydes in presence of potassium carbonate gave α, β-unsaturated carboxamidee with high E-selectivity and good yields. 相似文献
13.
ZHAO Pan LU Cui-fen YANG Gui-chun CHEN Zu-xing DONG Nian-guo SHI Jia-wei 《高等学校化学研究》2011,27(6):984-987
Polysubstituted cyclopropanes were efficiently prepared with poly(ethylene glycol)(PEG) as soluble support. The reaction of PEG-supported pyridinium ylide with arylidenemalononitrile(R=CN) or ethyl arylidenecyanoacetate(R=COOEt) in the presence of triethylamine(TEA) afforded PEG-supported cyclopropanecarboxylates, which were cleaved by 1% KCN/EtOH to obtain polysubstituted cyclopropanes with exclusive trans-selectivity and good yields. 相似文献
14.
Stereospecificsynthesisof(Z)-a,o-dehydroaminoacidsisofgreatimportanceinthepreparationofuncommonornatUralopticallypureaminoacids,because,ingeneral,(Z)-isomersaffordmuchhigherenantioselectivitieswithfasterratesthan(E)-isomersinthecatalyticasymmetrichydrogenation'.(Z)-isomersofethyl2-acylamido-4-phenylcrotonate2areimpoFtantprecursorsinthecourseofoursynthesisofL-homopheny1alaninel,akeysynthonformostcommerciallyimportantantihypertensiveACEinhibitorssuchasEnalapril,Benazepril,Lisinopril.Hereinwe… 相似文献
15.
16.
A stereoselective synthesis of ethyl (2E, 4Z)-2,4-deca-dienoate (1) is reported from E-pent-2en-4-yn-1-ol in five steps. 相似文献
17.
The title compound is prepared efficiently and stereoselectively by sodium methoxide induced Favorskii rearrangement and elimination of HBr from 4-methyl-1,3,4-tribromo-2-pentanone which is formed by direct bromination of mesityl oxide. The method provides mole quantities of the title compound. 相似文献
18.
松毛虫性信息素(5Z,7E)-十二碳二烯醇的立体选择性合成 总被引:2,自引:0,他引:2
从简单原料乙炔出发,通过炔对丙烯醛的加成反应得到7-溴代-(4Z,6E)-庚二烯醛,再经乙二醇保护、Pd催化偶联、水解、Wittig反应和还原等步骤,立体选择性地得到松毛虫性信息素(5Z,7E)-十二碳二烯醇,其结构通过IR,NMR和MS等技术得到确认. 相似文献
19.
S. Shivprakash 《合成通讯》2014,44(5):600-609
A synthetic method of producing (E)- and (Z)-isomers of 1-benzhydryl-4-cinnamylpiperazines in a specific ratio from corresponding benzhydrylpiperazine is described. Of the three compounds synthesized (5a–c), the ratio of E/Z-isomers remained around 15:85. The key intermediates, 1-benzhydryl-4-(2,2-dimethoxyethyl)piperazine derivatives (3a–c), were prepared by nucleophilic substitution reaction of benzhydrylpiperazines (2a–c) with chloroacetaldehyde dimethylacetal in good yield (up to 88%). Hydrolysis of 3a–c gave the corresponding aldehydes 4a–c, which when subjected to the Wittig reaction followed by column purification to afford 1a–c (E-isomers) and 6a–c (Z-isomers) in pure form. The isolated compounds were characterized by NMR and mass spectral analysis.
[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
20.
Ziyi Han Zhiwei Zheng Li Cai Dandan Zhou Changsheng Li Qiang Sui Shuai Liu Qi Gao 《Tetrahedron letters》2018,59(42):3773-3776
The Mitsunobu reaction of flavonoids and 3,4,6-tri-O-acetyl-2-deoxy-d-glucopyranose or 3,4,6-tri-O-benzyl-2-deoxy-d-glucopyranose is a very effective method for the stereoselective synthesis of flavonoid 2-deoxyglucosides. Since there is no C2 substituent on the sugar moieties, the observed α- or β-stereoselectivity was mainly controlled by the (acetyl or benzyl) protecting groups. Possible mechanistic insights are offered to explain the dual stereoselectivity. 相似文献