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以生物合成的SinenxanA(SIA)为起始物,在合成1,7,9-trideoxytaxol的路线中,化合物1为关键中间体,研究了以多种不同氧化剂、在不同条件下[1,2],对14-deoxy-SIA的13位进行烯丙氧化,得到不同结果,从中选出条件温和、产率较高的反应条件(见图1,表1). 相似文献
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环己烯烯丙位氧化研究 总被引:2,自引:0,他引:2
环己烯酮是一种医药中间体,较早的合成方法[1]采用冰醋酸为溶剂,铬酐为氧化剂,氧化环己烯生成环己烯酮,产率低,分离困难,且污染严重,较难实现工业化.目前环己烯酮的商品化在国内外都未实现.现在应用价廉的分子氧作氧源,在过渡金属催化剂存在下,催化氧化环己烯的研究已经很多[2~4],但大都集中在环氧化上,对烯丙位氧化研究甚少.本文以乙酰丙酮钴(Ⅱ)作为催化剂,以分子氧为氧源,在高压釜中催化氧化环己烯生成环己烯酮,考察了时间、温度、溶剂及外加物等的影响,并与常压带水条件下的反应结果进行了对比. 相似文献
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我国资源丰富的猪去氧胆酸(1)可以用作合成油菜甾醇内酯(2)、α-蜕皮甾酮(3)和维生素D代谢物4的原料.合成的关键是猪去氧胆酸侧链的改造.本文报道从猪去氧胆酸氧化脱羧所得到的△~(22)-甾烯(5)分别转变成合成上述化合物的中间体6,7和8,并利用从5经臭氧化制得的9合成了一个油菜甾醇内酯和α-蜕皮甾酮的共同中间体10. 相似文献
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环已烯烯丙位氧化研究 总被引:8,自引:0,他引:8
环己烯酮是一种医药中间体 ,较早的合成方法[1 ] 采用冰醋酸为溶剂 ,铬酐为氧化剂 ,氧化环己烯生成环己烯酮 ,产率低 ,分离困难 ,且污染严重 ,较难实现工业化。目前环己烯酮的商品化在国内外都未实现。现在应用价廉的分子氧作氧源 ,在过渡金属催化剂存在下 ,催化氧化环己烯的研究已经很多[2~4] ,但大都集中在环氧化上 ,对烯丙位氧化研究甚少。本文以乙酰丙酮钴 (Ⅱ)作为催化剂 ,以分子氧为氧源 ,在高压釜中催化氧化环己烯生成环己烯酮 ,考察了时间、温度、溶剂及外加物等的影响 ,并与常压带水条件下的反应结果进行了对比。1 实验部分1 .1… 相似文献
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胆汁酸为载体的肝靶向一氧化氮释放药物的设计与合成 总被引:1,自引:0,他引:1
新型肝靶向一氧化氮释放药物对许多肝脏疾病具有较好的治疗作用. 以胆酸和熊去氧胆酸作为药物的载体, 以氨基酸作为联接子, 以氨基酸的α羧基模拟胆酸或熊去氧胆酸分子24位羧基的负电性, 最大限度地保持胆酸或熊去氧胆酸的结构特征, 通过酰胺键将载体与一氧化氮供体硝酸酯偶联, 设计并合成了一系列新型肝靶向一氧化氮释放偶合物, 其结构经元素分析, IR, 1H NMR和MS光谱分析确证. 利用四氯化碳及对乙酰氨基酚所致小鼠急性肝损伤模型研究化合物对小鼠急性肝损伤的修复作用. 相似文献
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4-Amino-3-hydroxybutyric acid was synthesized from allyl cyanide in four steps in an overall yield of 38%. Ultrasonically promoted epoxidation of allyl cyanide with m-chloroperoxybenzoic acid giving oxiranylacetonitrile was used as a key step. 相似文献
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Ichikawa Y Hirata K Ohbayashi M Isobe M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(13):3241-3251
The first total synthesis of the peptidyl nucleoside antibiotic, blasticidin S (1), has been achieved by the coupling reaction of cytosinine (3) and blastidic acid (2). A key step in the synthesis of cytosinine (3) is the sigmatropic rearrangement of allyl cyanate 24; this reaction provided efficient and stereoselective access to 2,3-dideoxy-4-amino-D-hex-2-enopyranose (26 a). Further elaboration of 26 a gave methyl hex-2-enopyranouronate 29, and cytosine N-glycosylation of 31 using the Vorbrüggen conditions for the silyl Hilbert-Johnson reaction furnished the differentially protected cytosinine (32) in 11 steps from 2-acetoxy-D-glucal (14) (4.0 % overall yield). Synthesis of the Boc-protected blastidic acid 47 in nine steps starting from chiral carboxylic acid 35 (23 % overall yield) utilized Weinreb's protocol for the preparation of benzyl amide 38 and Fukuyama's protocol for the synthesis of the secondary amine 40. Assembly of the protected cytosinine (32) and blastidic acid (47) by the BOP method in the presence of HOBt, and finally elaboration to 1 by deprotection of the fully protected 54 established the total synthesis of blasticidin S (1). 相似文献
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合成了铬酸氢根季铵盐树脂,以它作为一种选择性氧化剂应用于烯丙醇的氧化反应,考察了温度、时间、溶剂、树脂与醇的物料比对氧化反应的影响。在优化的反应条件下,即以苯为溶剂,n(树脂):n(醇)=3.5:1,回流12h,丙烯醛产率达60.65%。实验表明,该季铵盐树脂能有效地将烯丙醇选择性地氧化为丙烯醛。 相似文献
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Nguyen-Trung NQ Botta O Terenzi S Strazewski P 《The Journal of organic chemistry》2003,68(5):2038-2041
3'-aminoacylamino-3'-deoxyadenosines, analogues of the antibiotic puromycin, have been synthesized from adenosine. They key 3'-azido derivative 10 was obtained through a 3'-oxidation/reduction/substitution procedure. A modified purification protocol on a larger scale was developed for the oxidation step using the Garegg reagent. The coupling reaction between an Fmoc-l-amino acid and the fully protected form of 3'-amino-3'-deoxyadenosine 11 furnished the aminoacylated compounds 12 in high yields. The puromycin analogues were obtained in 10 steps and up to 23% (14c) overall yield. 相似文献
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2,4-Methanoproline, a supposed non-proteinogenic anti-feedant, was synthesised in 5 steps starting from allyl benzyl ether 3 in 10% overall yield with an intramolecular nucleophilic substitution as the key step for the formation of the bicyclic skeleton. 相似文献
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Cuzzupe AN Hutton CA Lilly MJ Mann RK McRae KJ Zammit SC Rizzacasa MA 《The Journal of organic chemistry》2001,66(7):2382-2393
The total synthesis of the epidermal growth factor inhibitor reveromycin B (2) in 25 linear steps from chiral methylene pyran 13 is described. The key steps involved an inverse electron demand hetero-Diels-Alder reaction between dienophile 13 and diene 12 to construct the 6,6-spiroketal 11 which upon oxidation with dimethyldioxirane and acid catalyzed rearrangement gave the 5,6-spiroketal aldehyde 9. Lithium acetylide addition followed by oxidation/reduction and protective group manipulation provided the reveromycin B spiroketal core 8 which was converted into the reveromycin A (1) derivative 6 in order to confirm the stereochemistry of the spiroketal segment. Introduction of the C1-C10 side chain began with sequential Wittig reactions to form the C8-C9 and C7-C6 bonds, and a tin mediated asymmetric aldol reaction installed the C4 and C5 stereocenters. The final key steps to the target molecule 2 involved a Stille coupling to introduce the C21-C22 bond, succinoylation, selective deprotection, oxidation, and Wittig condensation to form the final C2-C3 bond. Deprotection was effected by TBAF in DMF to afford reveromycin B (2) in 72% yield. 相似文献
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An efficient synthesis of naturally occurring (R)-tylophorine is described. The alkaloid was prepared in seven steps from a known phenanthryl aldehyde with an overall yield of 14.2%. Asymmetric hydrogenation of an allyl alcohol was employed as a key step for installing a stereogenic center with good enantioselectivity (77% ee), and the ee value of the ω-chloro alcohol was improved to 95% by recrystallization. After azidation and oxidation of the enantio-enriched ω-chloro alcohol to the precursor of the Schmidt reaction, the chirality transfer in the stereospecific 1,2-migration furnished the chiral carbon in the alkaloid. Finally, a one-pot deformylation/Pictet-Spengler cyclization completed the total synthesis of (R)-tylophorine. 相似文献
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Unprecedentedly efficient and highly (≥98 %) stereoselective syntheses of mycolactones A and B side chains relied heavily on Pd‐catalyzed alkenylation (Negishi version) and were completed in 11 longest linear steps from ethyl (S)‐3‐hydroxybutyrate in 12 % and 11 % overall yield, respectively, roughly corresponding to an average of 82 % yield per step. The synthesis of mycolactone core was realized by using Pd‐catalyzed alkenyl? allyl coupling and an epoxide‐opening reaction with a trialkylalkenylaluminate as key steps. Fully hydroxy‐protected mycolactones A and B of ≥98 % isomeric purity were synthesized successfully for the first time. However, unexpected 4:3–5:4 inseparable mixtures of mycolactones A and B were obtained upon deprotection. 相似文献
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Byung Hyun Kim 《Tetrahedron letters》2006,47(44):7727-7730
2,6-Dimethylnaphthalene (2,6-DMN), a key raw material for poly(ethylene naphthalate) (PEN), was selectively synthesized via a two-step process in an overall 66% yield from commercially available 4-bromotoluene and 3-methyl-3-buten-1-ol. The ligand-free Heck reaction of the starting materials produced γ-(p-tolyl)-substituted aldehyde that was cyclized with an acid to give 2,6-DMN after in situ oxidation. No other isomers of 2,6-DMN were found. 相似文献