共查询到20条相似文献,搜索用时 15 毫秒
1.
A short and efficient synthesis of the commercially unavailable (R)-(+) isomer of perillaldehyde from (+)-limonene oxide has been developed. 相似文献
2.
《合成通讯》2013,43(14):2475-2482
Abstract A novel process has been developed for the synthesis of (6R,7R)-7-amino-3-hydroxymethyl cephalosporanic acid (7-AHCA) using a combination of reagents [triethyl amine/tetrabutyl ammonium hydroxide (TBAH)] at ambient temperature, with improved yield. This intermediate was exploited for the synthesis of cefuroxime acid and its sodium salt. 相似文献
3.
以1-磺丁基-3-甲基咪唑硫酸氢盐离子液体(b)为反应介质,7-氨基头孢烷酸(7-ACA,2)为原料,与4-甲基-5-甲酰基噻唑经缩合反应制得(6R,7R)-7-氨基-3-[2-(4-甲基-5-噻唑)乙烯基]-8-氧代-5-硫-1-氮杂双环[4.2.0]辛-2-烯-2-羧酸(7-ATCA,1),其结构经1H NMR,13C NMR和IR表征。考察了离子液体及其用量,原料摩尔比r[n(4-甲基-5-甲酰基噻唑)∶n(2)],反应温度和反应时间对1收率的影响。在最佳反应条件[b为反应介质,b用量为20 m L,r=1.3,于65℃反应5 h]下,1收率可达90%以上。 相似文献
4.
Xavier Verdaguer Iolanda Marchueta Jordi Tormo Albert Moyano Miquel A. Perics Antoni Riera 《Helvetica chimica acta》1998,81(1):78-84
A convenient preparation of (1R,2S,3R,4S)-3-(neopentyloxy)isoborneol (= (1R,2S,3R,4S)-3-(2,2-dimethyl-propoxy)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol; 1a ), a valuable chiral auxiliary, is described. The synthesis involves six steps starting from the readily available camphorquinone ( 5 ) and gives 1a in 48% overall yield. The key step is the chemoselective hydrolysis of the less hindered 1,3-dioxolane moiety in the camphorquinone di-acetal 4 . 相似文献
5.
Butadiene-2, 3-dicarboxylic acid (fulgenic acid) has been reported previously to be avaialable in ca. 1% yield following basic hydrolysis of the corresponding dimethyl ester.1 相似文献
6.
以1,5-戊二醇为起始原料,用Evans手性助剂诱导的烷基化反应构造了C-2手性中心,用Ohira-Bestmann试剂制备了末端炔基,通过13步反应,合成了(R)-2-甲基-7-炔-辛酸,总收率为17.1%,e.e.值大于99%. 相似文献
7.
Gard Gjessing Lars-Inge Gammelster Johnsen Simen Gjelseth Antonsen Jens M. J. Nolse Yngve Stenstrm Trond Vidar Hansen 《Molecules (Basel, Switzerland)》2022,27(7)
Monohydroxylated polyunsaturated fatty acids belonging to the oxylipin class of natural products are present in marine and terrestrial sources as well as in the human body. Due to their biological activities and role in diverse biosynthetic pathways, oxylipins biosynthesized from eicosapentaenoic acid and arachidonic acid have attracted great interest from the scientific community. One example is 3-hydroxyeicosapentaenoic acid where the absolute configuration at C-3 has only been tentatively assigned. In this paper, studies on acetate type aldol reactions that enabled the preparation of 3-(R)-hydroxyeicosapentaenoic acid (3R-HETE, 2) and its enantiomer are presented. 相似文献
8.
a short, convenient and large scale synthesis of (S)-(+)-2-(2-methoxyphenyl) propanoic acid, involving a resolution of the corresponding racemic acid with quinine, is reported. 相似文献
9.
Vladimir V. Samukov 《合成通讯》2013,43(17):3213-3217
The two-step synthesis of 3-(2-pyridyldithio)propionic acid is described, which includes the chlorination of 2,2′-dipyridyl disulfide with sulfuryl chloride and the reaction of the formed 2-pyridylsulfenyl chloride with 3-mercaptopropionic acid. 相似文献
10.
《Tetrahedron: Asymmetry》2001,12(23):3235-3240
(±)-3-(2-Aminopropyl)-7-benzyloxyindole 1, assembled from 7-benzyloxyindole 3 in 59% overall yield, is resolved with O,O′-di-p-toluoyl l-(2R,3R)-tartaric acid 7 into (R)-1, a key intermediate of AJ-9677 2 (selective adrenaline β3-agonist) in 99.5% e.e. and 36% overall yield. The unwanted enantiomer (S)-1 (61.9% e.e.; recovered in 57% yield from the crystallization filtrate) can be reused in another round of resolution after its enantiomeric purity is lowered to 3.7% by Raney Co treatment under a hydrogen atmosphere. 相似文献
11.
Hakansson AE Koshkin AA Sorensen MD Wengel J 《The Journal of organic chemistry》2000,65(17):5161-5166
Synthesis of the diastereoisomeric LNA (locked nucleic acid) nucleosides 1-(2-O,4-C-methylene-alpha-L-ribofuranosyl)thymine (6) and 1-(2-O,4-C-methylene-alpha-L-xylofuranosyl)thymine (13) are reported via convenient reaction cascades from di-O-p-toluenesulfonyl and tri-O-methanesulfonyl nucleoside derivatives 3, 7, and 10. 相似文献
12.
13.
Jie YAN Min ZHU College of Pharmaceutical Sciences Zhejiang University of Technology Hangzhou College of Biological Environmental Sciences Zhejiang Shuren University Hangzhou 《中国化学快报》2005,16(4)
Coloradocin, a novel macrolide antibiotic from cultures of Actinoplanes coloradoensis1exhibits activity against pathogenic anaerobic and microaerophilic species2. Because itslow toxicity and substantial oral activity3, , as well as its unusual structure5, several 4research groups initiated approaches towards the synthesis of coloradocin6, whichculminated in the synthesis of 18-deoxynargenicin A1 by Kallmerten et al.7. … 相似文献
14.
Vanga S. Rao 《合成通讯》2013,43(20):2915-2920
A convenient method for the preparation of cis- and trans-1-mercapto-3-azidocyclobutane from 1,1-cyclobutanedicarboxylic acid is described. The long range “W” coupling pathway was used to distinguish the cis isomer from the trans isomer. 相似文献
15.
16.
A convenient 3-step synthesis of (R)-7-hydroxycarvone (2) has been developed starting from (S)-alpha-pinene (7), using photooxygenation, oxidation, and fragmentation reactions. An improved synthesis of epoxy alcohol 6 and an unusual Ti(OiPr)(4) catalyzed hydroxy epoxide to keto alcohol rearrangement are also described. 相似文献
17.
18.
A convenient approach for the preparation of (2S,3R,4R,5S,6R)-2-(3-(4-ethylbenzyl)-4-chlorophenyl)-6-(hydroxymethyl)- tetrahydro-2H-pyran-3,4,5-triol I is developed. The target compound via four steps is synthesized from 4-bromo-2-(bromomethyl)- 1-chlorobenzene and the isomers of undesired ortho-products were avoided during the preparation. 相似文献
19.
A one step synthesis of (E)-4-oxo-2-butenoic acid ethyl ester via the reaction of ethyl 2-ethoxy-2-hydroxyacetate and (formylmethylene)triphenylphosphorane is described. The method proceeds in good yield on a molar scale. 相似文献
20.
In 1977 Tamaki1 et al have isolated and synthesized2 (Z)-7-nonadecen-ll-one (la) and (Z)-7-eicosen-l1-one (1b) which are active components of the female sex pheromones of the peach fruit moth Carposina niponensis Walsingham, a major economic pest of apple, peach and other fruits of Japan. We report in this communication a practical, convenient and stereospecific route to 1a and 1b. 相似文献