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11.
在通过Diels-Alder反应建立各种含氮六员环的反应中,亚胺是一个最有用的亲双烯试剂。该法应用简便、并显示出较好的位置选择性和立体选择性。对其在生物碱类合成中的应用也作了综述。 相似文献
12.
A novel alkaloid with an unprecedented ring system consisting of a dodecahydro-7-oxa-9a-aza-benzo[a]azulene ring (1), has been isolated from cultures of Clitocybe concava (Basidiomycetae). Its structure and relative stereochemistry were elucidated on the basis of spectroscopic data. Concavine presents a weak antibacterial activity. 相似文献
13.
A method for synthesizing substituted quinolines using ruthenium-catalyzed ring-closing metathesis as a key step has been developed. Substituted 1,2-dihydroquinolines, 4-silyloxy-1,2-dihydroquinoline and 4-methoxy-1,2-dihydroquinoline, were successfully synthesized in excellent yields via ene-ene metathesis and silyl or alkyl enol ether-ene metathesis, respectively. The synthetic intermediates of the antimalarial agents quinine, chloroquine, and PPMP-quinine hybrid were efficiently synthesized by this methodology. 相似文献
14.
Minyan Tang 《Tetrahedron》2004,60(27):5759-5767
A diastereoselective synthesis of the pyrrolizidine alkaloid, (+)-1-epiaustraline has been achieved via a diastereoselective syn-dihydroxylation of a pyrrolo[1,2-c]oxazol-3-one precursor that was readily prepared by a RCM reaction. Attempts to extend this methodology to the synthesis of australine were not successful since the final pyrrolidine ring closure to produce the desired pyrrolizidine of the target molecule was not productive. 相似文献
15.
16.
Nathaniel L SegravesSuzette Lopez Tyler A JohnsonSadri A Said Xiong FuFrancis J Schmitz Halina PietraszkiewiczFrederick A Valeriote Phillip Crews 《Tetrahedron letters》2003,44(17):3471-3475
The structural variations and bioactivity properties of the alkaloids in the fascaplysin (1) and the reticulatine (3) families were examined. Four organisms were analyzed consisting of two collections of the sponge Fascaplysinopsis reticulata and two collections of the tunicate Didemnum sp. Reported are the isolation of three new compounds: 3-bromofascaplysin (2), 14-bromoreticulatine (4), and 14-bromoreticulatate (6) along with reticulatate (5) previously known as a semi-synthetic product of 1. Compounds 1 and 5 showed selectivity in a cell based cytotoxicity assay. 相似文献
17.
Two new alkaloids nitraramidine and nitraraidine were isolated from the aerial part of Nitraria sibirica. Their structures were established using spectral data and chemical transformations. 相似文献
18.
An investigation of the alkaloidal constituents of the leaves of Catharanthus roseus has led to the isolation of a new alkaloid, “rosicine”, to which structure (1) has been assigned on the basis of spectroscopic studies. Two other alkaloids isolated have been identified as 14, 15-dehydroepivincadine and 19-hydroxytabersonine. 相似文献
19.
本文综述了近年来不对称Diels-Alder反应中手性催化剂研究的进展,对各类手性催化剂的性能和特点作了简要介绍. 相似文献
20.
自然界广泛存在铁屎米酮(Canthinone)骨架(1)的生物碱。在夹竹桃科Pleiocarpa talbo-tii W.中,就发现有光学活性的具有六氢铁屎米酮骨架的生物碱存在。另据报道,3-位上有取代基的六氢铁屎米酮化台物具有抗缺氧活性、扩张血管活性和毒性作用。对这类生 相似文献