共查询到20条相似文献,搜索用时 15 毫秒
1.
Trost BM Frontier AJ Thiel OR Yang H Dong G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(35):9762-9776
Bryostatins, a family of structurally complicated macrolides, exhibit an exceptional range of biological activities. The limited availability and structural complexity of these molecules makes development of an efficient total synthesis particularly important. This article describes our initial efforts towards the total synthesis of bryostatins, in which chemoselective and atom-economical methods for the stereoselective assembly of the ring C subunit were developed. A Pd-catalyzed tandem alkyne-alkyne coupling/6-endo-dig cyclization sequence was explored and successfully pursued in the synthesis of a dihydropyran ring system. Elaboration of this methodology ultimately led to a concise synthesis of the ring C subunit of bryostatins. 相似文献
2.
Temperature-dependent separation of bryostatin 18 and 10 by high performance liquid chromatography 总被引:1,自引:0,他引:1
Summary The temperature-dependent separation of bryostatins by HPLC was examined on an octadecyl bonded stationary phase, using column
temperatures between 0 and 40°C and mobile phase temperatures from 0 to 25°C. The retention time and resolution of bryostatins
changed drastically and separation improved with decreasing temperature. A column temperature of less than 5°C and a mobile
phase temperature of less than 15°C is recommended for a good resolution of bryostatins for routine work. 相似文献
3.
高效液相色谱-质谱法鉴定总合草苔虫中的草苔虫内酯成分 总被引:2,自引:0,他引:2
采用高效液相色谱分离与质谱检测的联用技术,对总合草苔虫中的草苔虫内酯成分进行定性分析。在以体积比为80∶20的甲醇-水溶液为流动相、采用ODS柱进行分离的色谱条件下,10种草苔虫内酯成分均可获得良好的分离。分析结果表明:深圳大亚湾产地的总合草苔虫中共含有9种已知和1种未知的草苔虫内酯成分。已知成分分别是bryostatin 4,5,6(9),7,8,10,16,17,18,其中bryostatin 7和17是首次从中国海域总合草苔虫中发现的2种痕量草苔虫内酯。该方法简便、准确、灵敏度高,可以很好的对总合草 相似文献
4.
Jiang Biao 《高等学校化学研究》2001,17(3)
The study of natural product has long been motivated by a quest for some benefit to man, the discover. Recent years have witnessed growing attention to the isolation, identification and synthesis of the marine natural. Although marine organisms do not have a long history of medicine applications like terrestrial plants, some marine organisms have left an extensive record of hazard to mankind. The isolation and identification of saxtoxin, tetradotoxin and lyngbyatoxin resulted from such reported. The marine biosphere has long held great promise as source of anticancer compounds, while a number of screening efforts has indicated a much higher percentage of antineplastic and antitumor activity than terrestrial plants. Several marine natural products have made their appearance in clinical trials at the National Cancer Institute, such as the didemnis, , bryostatins, This finds marine invertebratehave reinvigorated interest and effort in anticancer agent from marine invertebrate. 相似文献
5.
Vinylic iodides were identified as useful intermediates for the synthesis of the C17-C27 fragment of the bryostatins with control of the geometry of the exocyclic methoxycarbonylmethylene group. Following literature precedent, the Piers (E)-stereoselective addition of tributyltin hydride to an alkynoate followed by ester reduction and tin-iodine exchange gave vinylic iodides that could be used to form the C20-C21 bond of the bryostatins. Chelation controlled addition of lithiated 3-silyloxypropynes to 2-alkoxyaldehydes followed by reductive iodination was used to prepare vinylic iodides that could be used in the complementary assembly of the C21-C22 bond of the bryostatins. Initial studies of the synthesis of intermediates for metathesis studies using metal catalysed reactions of a vinylic iodide for C21-C22 bond formation were complicated by cyclisation reactions. 相似文献
6.
Dipl.‐Chem. Max Bielitza Prof. Dr. Jörg Pietruszka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(25):8300-8308
The synthesis of a putative biosynthetic precursor of psymberin including a formal synthesis of the natural product is described. The key step towards the densely functionalized tetrahydropyran core was an enantioselective catalytic Mukaiyama aldol reaction using a titanium(IV)–BINOL catalyst system. syn‐Selective reduction followed by ozonolysis led to a rapid assembly of the tetrahydropyran ring. This flexible approach also allows the synthesis of similar fragments of other complex molecules such as bryostatins and pederins. The syn‐selective coupling between the tetrahydropyran and the aromatic aldehyde was achieved using a boron‐mediated aldol reaction which was followed by further transformations to complete the synthesis of the precursor as well as the formal synthesis of the natural product. 相似文献
7.
《液相色谱法及相关技术杂志》2012,35(4):553-561
Abstract A reversed-phase high performance liquid chromatographic (RP-8; acetonitrile-water gradient) separation procedure was developed for detecting bryostatins 1–12, using a photodiode array detector system. While bryostatins 6 and 9 were found to co-elute they were easily separated using a silica gel column with 9:1 n-hexane-n-propanol as eluent. 相似文献
8.
The bryostatins belong to an important class of complex molecules with interesting antitumoral activity. A related structural compound, exiguolide, has been recently isolated from the marine sponge Geodia exigua Thiele. The isolation, structural determination and synthesis of this compound are reported. 相似文献
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10.
《液相色谱法及相关技术杂志》2012,35(3):583-598
Abstract An HPLC method has been developed to detect and quantitate bryostatins 1 and 2 from crude extracts of B. neritina. This, coupled with a 3H-phorbol dibutyrate binding assay and photodiode array-acquired uv spectra makes possible the evaluation of crude extracts in a rapid, sensitive and specific manner. 相似文献
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13.
Christian Lahanier 《Mikrochimica acta》1991,104(1-6):245-254
Scientific methods applied to the study of works of art are varied (examination, analysis and dating) and must be chosen with care in accordance with the object of the research. This paper briefly sets out the state of the art highlighting the development and applications of non-destructive methods. Such methods come under either the use of electromagnetic or particle radiation for the formation of images based on shape, development technique, or, on the other hand, the quantitative determination of elements down to and including their traces, isotopes or microsurfaces for the purpose of identifying the matter, its date, origin and development. 相似文献
14.
Hiroyuki Hosomi Shigeru Ohba Ken Ohmori Tetsuo Obitsu Yasuyuki Ogawa Yuichi Ishikawa Shosuke Yamamura Shigeru Nishiyama 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):e142-e143
The absolute configuration was determined for the title compound, (+)‐C18H24O3S, (I), which was prepared in a synthetic study on the natural products, bryostatins. 相似文献
15.
Trost BM Yang H Brindle CS Dong G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(35):9777-9788
This article describes chemoselective and atom-economic methods for the stereoselective assembly of the ring A and B subunits of bryostatins. A Ru-catalyzed tandem alkene-alkyne coupling/Michael addition reaction was developed and applied to the synthesis of bryostatin ring B. We explored an acetylide-mediated epoxide-opening/6-exo-dig cyclization route to access the bryostatin ring A, although ring A was eventually furnished through an acid-catalyzed tandem transketalization/ketalization sequence. In addition, a dinuclear zinc-catalyzed methyl vinyl ketone (MVK) aldol strategy was evaluated for the construction of the polyacetate moiety. Utilization of these methods ultimately led to the rapid assembly of the northern bryostatin fragment containing both the ring A and B subunits. 相似文献
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Microporous organic polymers (MOPs) have attracted considerable research interest because of their well-defined porosity, high surface area, lightweight nature, and tunable surface chemistry. The morphology of MOPs are demonstrated to play a significant role in various applications although limited examples manifesting the importance of the MOP morphology in numerous applications have been reported. This review summarizes the recent progress in the design of MOPs using different techniques, including hard and soft template and direct synthesis methods. In addition, their applications, which possibly attribute to their shape, are discussed. Furthermore, the advantages and disadvantages of different methods are discussed, as well as their development and future challenges. 相似文献
18.
Starting from 8-oxabicyclo[3.2.1]oct-6-en-3-one and racemic 2,2-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one, the C1-C16 segment of the bryostatins has been synthesized in 30 steps and 9% overall yield (17 steps longest linear sequence). Fragment coupling by dithiane strategy and protecting group manipulations provided an advanced chemodifferentiated northern half segment. 相似文献
19.
Ultrathin oxide nanofibers are widely used in an array of catalytic applications toward energy conversion and environmental protection. Remarkable progress has been made with regard to the development of engineering oxide nanofibers into unique structures to suit or enable various functions. We aim to provide a comprehensive overview of oxide nanofibers, including the structure engineering, derivates, assemblies and their applications. We begin with a brief introduction to the production of nanofibers with diversified compositions, structures and properties, followed by discussions of the wet-chemistry derivates. Afterward, we discuss the applications of catalytic oxide nanofibers, including electrocata-lysis, photocatalysis and thermal-catalysis. Then we highlight the most significant role of oxide nanofibers as catalyst support for the immobilization of metal nanoparticles. Moreover, we showcase the advanced assemblies based on oxide nanofibers, including their use as multi-functional membranes and foams. In the end, we offer perspectives on the challenges, opportunities and new directions for future development. 相似文献