共查询到20条相似文献,搜索用时 15 毫秒
1.
Lymphostin (1), a novel immunosuppressant, has been synthesized from tryptophan through six kinds of regioselectively oxidative reactions. 相似文献
2.
Quercetin 3-O-[α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside]-7-O-β-d-glucopyranoside (calabricoside A), a new flavonol triglycoside isolated from the aerial parts of Putoria calabrica showing strong radical scavenging activity, was synthesized through a combination of phase-transfer-catalyzed C-3 glycosylation and AgOTf promoted homogeneous C-7 glycosylation in CH2Cl2. 相似文献
3.
(-)-Nakadomarin A is a member of manzamine alkaloid isolated from a marine sponge and have a unique hexacyclic structure. The first total synthesis of (+)-nakadomarin A, an enantiomer of natural product, has been accomplished from stereochemically defined 4-oxopiperidin-3-carboxylic acid derivative. The synthesis established the structure of nakadomarin A including absolute configuration. 相似文献
4.
Trichostatin D and 6-epi-trichostatin D have been stereoselectively synthesized through a remote stereoinduction with a chiral vinylketene silyl N,O-acetal and glycosylation of hydroxyimide under Mitsunobu conditions. 相似文献
5.
Ligudentatin A 1, a new phenolic norsesquiterpenes, was first synthesized starting from (+)-perillaldehyde 3 through five steps, successively, in an overall yield of 20.8%. The key steps were the Diels-Alder reaction and aromatization of enone to phenol. 相似文献
6.
The first total synthesis of telephiose A (1), a novel trisaccharide ester having two acetyl groups and two benzoyl groups, was achieved by using glucosyl donor 6 and disaccharide acceptor 12. The crucial key step was the stereoselective construction of the β-d-glucosidic linkage featuring the neighboring group participation of the 2-O-N-phenylcarbamoyl group (of donor 6), which can be selectively deprotected in the presence of acetyl and benzoyl groups. Donor 6 was prepared from d-glucose in eight steps (33% yield), whereas acceptor 12 was prepared from sucrose in six steps (35% yield). Precursors 6 and 12 were reacted in subsequent reactions (five steps) to afford 1 in 22% yield. 相似文献
7.
A highly convergent asymmetric total synthesis of emericellamide A, a 19-membered antibacterial depsipeptide isolated from the co-culture of an Emericella sp. (strain CNL-878) and a Salinispora arenicola (strain CNH-665) is described. 相似文献
8.
Qi Chen 《Tetrahedron letters》2006,47(48):8489-8492
The first total synthesis of natural cytotoxic agent, sporiolide B, is described. d-Xylose was used as the chiral template to pre-control the absolute configuration during the synthesis. Yamaguchi esterification and ring closing metathesis greatly facilitate the target compound accomplishment. 相似文献
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10.
A concise, high yielding route to the naturally occurring enantiomer of grenadamide utilizing a 3,6-disubstituted 1,2-dioxine starting material is presented. The route allows for ease in synthesizing grenadamide derivatives varying at cyclopropyl carbons 2 and 3, with access to both enantiomers. Evidence for phosphorus-assisted deprotonation of 1,2-dioxines is also discussed. 相似文献
11.
The first asymmetric total synthesis of prianosin B (1) is described. Formation of the 16,17-dehydropyrroloiminoquinone skeleton from the pyrroloiminoquinone unit is a key step in this synthesis. Thus, the detosylation and dehydrogenation reactions of the pyrroloiminoquinone unit are caused by the presence of a catalytic amount of NaN3. 相似文献
12.
Henderson AR Stec J Owen DR Whitby RJ 《Chemical communications (Cambridge, England)》2012,48(28):3409-3411
The first total synthesis of (+)-mucosin has been completed allowing assignment of the absolute stereochemistry of the natural product. A zirconium induced co-cyclisation was utilised to install the correct stereochemistry of the four contiguous stereocentres around the unusual bicyclo[4.3.0]nonene core. 相似文献
13.
The first total synthesis of the natural cytotoxic agent sporiolide A has been accomplished from D-glucal in 16 steps with 6.1% overall yield. Carbohydrates were applied as the chiral templates to manipulate the absolute configuration during the synthesis. Pyridinium chlorochromate (PCC)-promoted transformation of the cyclic enol-ether to lactone, followed by Yamaguchi esterification and intramolecular ring closure metathesis, greatly facilitates synthesis of the target compound. 相似文献
14.
The first total synthesis of the biologically significant bis-indole alkaloid dragmacidin D (5) has been achieved. Thermal and electronic modulation provides the key for a series of palladium-catalyzed Suzuki cross-coupling reactions that furnished the core structure of the complex guanidine- and aminoimidazole-containing dragmacidins. Following this crucial sequence, a succession of meticulously controlled final events was developed leading to the completion of the natural product. 相似文献
15.
Tohma H Harayama Y Hashizume M Iwata M Kiyono Y Egi M Kita Y 《Journal of the American Chemical Society》2003,125(37):11235-11240
The first stereoselective total synthesis of a potent antitumor alkaloid, discorhabdin A (1), which is a unique sulfur-containing pyrroloiminoquinone alkaloid, is described. The key step in the stereocontrolled total synthesis of 1 involves both a diastereoselective oxidative spirocyclization using a hypervalent iodine(III) reagent and an efficient construction of the labile and highly strained N,S-acetal skeleton. These methodologies provide a breakthrough in the total syntheses of these promising new antitumor agents, discorhabdins and their analogues, which should serve as valuable probes for structure-activity studies. 相似文献
16.
Bhatt U Christmann M Quitschalle M Claus E Kalesse M 《The Journal of organic chemistry》2001,66(5):1885-1893
The first total synthesis of ratjadone was achieved using a highly convergent approach joining three subunits together with a Wittig olefination and a selective Heck reaction as the pivotal steps. Besides establishing a robust and reliable route for the synthesis of this orphan ligand, the configuration of unknown stereocenters could also be determined. This synthesis not only provides an additional access to a biologically important compound but also enables the synthesis of structural analogues for biological target identification. 相似文献
17.
The first enantiospecific total synthesis of the tricyclic sesquiterpene (+)-seychellene, starting from (R)-carvone via (S)-3-methylcarvone, has been accomplished employing a combination of an intermolecular Michael addition-intramolecular Michael addition sequence and an intramolecular alkylation reaction for the generation of the two vicinal quaternary carbon atoms. 相似文献
18.
Palakodety Radha Krishna Sunchu Prabhakar Chittela Sravanthi 《Tetrahedron letters》2013,54(7):669-671
Herein we report the first stereoselective total synthesis of nicotlactone A via acid catalyzed acetonide deprotection followed by intramolecular lactonization in one pot as the key step. 相似文献
19.
The first stereoselective total synthesis of quinine. 总被引:1,自引:0,他引:1
G Stork D Niu R A Fujimoto E R Koft J M Balkovec J R Tata G R Dake A Fujimoto 《Journal of the American Chemical Society》2001,123(14):3239-3242
The first entirely stereoselective total synthesis of (-)-quinine is reported. 相似文献
20.
The first total synthesis of usabamycins A and C from inexpensive and readily available amino acids – homoalanine and glycine and featuring a stereoselective Ireland-Claisen rearrangement as well as a novel 7-membered ring formation reaction is described. 相似文献