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二萜生物碱的~(13)C核磁共振谱 总被引:2,自引:0,他引:2
本文通过对186个二萜生物碱及其衍生物的~(13)C NMR谱数据的分析比较,就以下几方面作了归纳总结:①信号归属的方法;②常见取代基OCH_3、NCH_3、、NCH_2CH_3、OCOCH_3、的化学位移范围;③季碳和某些特定碳的化学位移规律。某些特定结构,如C_(20)二萜生物碱中的噁唑烷环以及C_(20)差向异构体等的~(13)C NMR谱特征;④C_(19)二萜生物碱中不同位置上取代基(H→OH、H→OMe、OH→OAc、OH→OMe、OH→C=O)效应和立体化学效应。这些归纳总结有助于此类化合物结构的阐明。 相似文献
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复方中药四逆汤中乌头碱类二萜生物碱的电喷雾串联质谱研究 总被引:9,自引:0,他引:9
利用电喷雾串联质谱方法不经柱分离而直接分析复方中药四逆汤中二萜生物碱的组成,乌头碱类二萜生物碱在质谱条件下形成质子化分子,一种生物碱对应一个分子离子峰.检测到了苯甲酰单酯型、双酯型和脂类生物碱等18种二萜生物碱,其中苯甲酰中乌头原碱等单酯型生物碱是四逆汤中的主要生物碱成分. 相似文献
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The nigellamine alkaloids are dolabellane diterpenes displaying potent lipid metabolism-promoting activity. Total synthesis of (+)- and (-)-nigellamine A2 has been accomplished. Absolute stereochemistry of synthetic nigellamine A2 was established through an intramolecular asymmetric allylic alkylation using a Pd(phosphinooxazoline) catalyst. Other notable transformations include a radical alkynylation, a diastereoselective Nozaki-Hiyama-Kishi cyclization, and a regio- and stereoselective catalytic epoxidation. On the basis of X-ray crystallographic analysis of an optically active intermediate, we have confirmed the assigned absolute stereochemistry of the natural product. Minor modifications of the synthetic sequence outlined here should provide access to the other nigellamine alkaloids. 相似文献
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Boyd DR Sharma ND Loke PL Malone JF McRoberts WC Hamilton JT 《Organic & biomolecular chemistry》2007,5(18):2983-2991
A range of seventeen quinoline alkaloids, involving several types of oxidations during their biosynthetic pathways, have been isolated from leaves of Choisya ternata. In addition to the nine known quinoline alkaloids, eight new members of the furoquinoline family, derived mainly from prenylation at C-5 (including two novel hydroperoxides), have been identified. The absolute configurations and enantiopurity values of all chiral quinoline alkaloids have been determined. One of the isolated alkaloids, 7-isopentenyloxy-gamma-fagarine, has been used as a precursor for the chemical asymmetric synthesis of the enantiopure alkaloids: evoxine, anhydroevoxine and evodine. The possible roles of oxygenase and other oxygen-atom-transfer enzymes, in the biosynthetic pathways of the C. ternata alkaloids, have been discussed. 相似文献
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This review covers natural products (secondary metabolites) with reported growth inhibitory activity towards Mycobacterium tuberculosis or related organisms. Such compounds have been isolated from a variety of sources including terrestrial and marine plants and animals, and microorganisms, with the express intent of identifying novel scaffolds for the development of new antituberculosis agents. The literature from January 2003 to December 2005 (inclusive) is reviewed and 146 references to 353 compounds are cited. The compounds are presented in order of chemical type, namely lipids/fatty acids and simple aromatics, phenolics and quinones, peptides, alkaloids, terpenes (monoterpenoids, diterpenes, sesquiterpenes and triterpenes), steroids and miscellaneous structures. 相似文献
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Hong Ping HE Yue Mao SHEN Xiao Sheng YANG Bin Gui WANG Ling LI Xiao Jiang HAO * Laboratory of Phytochemistry Kunming Institute of Botany the Chinese Academy of Sciences Kunming . The Key Laboratory of Chemistry for Natural Prod 《中国化学快报》2001,(1)
Spiraea japonica L. (Rosaceae) is widely distributed in Yunnan Provence, P. R. China. Previous chemical investigations on S. japonica and its varieties have led to the report of 7 new atisane-type diterpenoids and 38 new diterpene alkaloids of atisine- and hetisine-type1-11. This paper describes the isolation and structure elucidation of two new diterpene alkaloids named spiratines A and B (1-2). Their structures were elucidated on the basis of 1D and 2D NMR experiments (HMQC, HMBC, 1… 相似文献
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Copp BR 《Natural product reports》2003,20(6):535-557
This review covers the literature published between January 1990 and December 2002 (inclusive) for natural products with reported antimycobacterial activity, with 248 citations to 352 compounds isolated from both terrestrial and marine sources The compounds are presented in order of chemical type, namely lipids/fatty acids and simple aromatics phenolics and acetogenic quinones, peptides, alkaloids, terpenes (monoterpenoids, diterpenes, sesquiterpenes, sesterterpenes and triterpenes) and steroids. 相似文献
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3-Methylpyrrolidine alkaloids 1-5,isolated from the poison gland of several species of ants Leptothoracini (Myrmicinae), have been found to be pheromones and chemical weapons of them[1,2].Since these alkaloids are only available at nanogram scale, the development of asymmetric synthesis is of importance, in particular for evaluating their bioactivities. 相似文献
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This paper presents a review on kaurane diterpenes and their glycoside derivatives, covering aspects of their occurrence, biological activities and the synthesis of these natural products and their analogues. First, it shows and classifies diterpenes, in accordance with the already established structural criteria in the literature. Then, kaurane diterpenes are presented, focusing on their chemical structures, occurrence in the plant kingdom and their main, recently described, biological activities. Moreover, the most significant works, published between 1964 and November 2006, which describe the total synthesis or structural transformations of some kaurane diterpenes, including either semisynthetic and/or microbiological methodologies, are consisely reviewed. At this point, some general considerations on glycosides are introduced, and kaurane glycosides are presented and discussed on the basis of their toxic importance and occurrence in the plant kingdom, having focused on related aspects of their biological activities and the relationships between these activities and the structural factors of their molecules. Finally, the principal methods of glycosidation by enzymatic and chemical processes are both presented, and a few papers on the synthesis of kaurane glycosides are succinctly discussed. 相似文献
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Héctor E. Montenegro Dr. Pedro Ramírez‐López Dr. María C. de la Torre Dr. María Asenjo Miguel A. Sierra Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(12):3798-3814
Two parallel approaches for preparing diverse and highly symmetrical homohybrids derived from a series of mono‐ and diterpenes, steroids, and alkaloids are reported. Both procedures are based on the mono‐addition of bis(alkynyl) dilithium reagents to natural products having a carbonyl group to produce the corresponding alkynyl derivatives. The Glaser–Hay Cu‐promoted homocoupling of these alkynyl natural product mono‐adducts as well as the Huisgen Cu‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction resulted in the synthesis of steroid‐, terpene‐, and alkaloid‐based homohybrid derivatives incorporating diverse spacers to join the natural product scaffolds. Straightforward entries to novel closed highly symmetrical and complex estrone‐based macrocyclic and cage architectures by means of the Glaser–Eglinton homocoupling and the CuAAC reaction have been devised. 相似文献
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Four new alkaloids have been isolated during chemical investigations into a southern Australian marine sponge, Stelletta sp. Detailed spectroscopic analysis, supported by chemical degradation and partial synthesis, permitted structure elucidation of bistellettazines A-C ( 1- 3), the first reported examples of terpenyl-pyrrolizidine conjugates, and bistellettazole A ( 4), a unique cyclic terpenyl-imidazole conjugate. The alkaloids 1- 4 feature unprecedented carbon skeletons that are proposed to share a common convergent biosynthetic origin, arising via the biogenic equivalent of a Diels-Alder addition between two hypothetical polyenyl norsesquiterpene precursors. 相似文献
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Two novel migrated pimarane-type diterpenes named neoorthosiphols A (1) and B (2) were isolated from the water decoction of the leaves of Orthosiphon aristatus (Lamiaceae), which has been prescribed in Javanese traditional medicine (jamu) for the treatment of hypertension, etc. The absolute chemical structures have been elucidated on the basis of physicochemical properties. It has been found that two migrated pimarane-type diterpenes (1, 2), four isopimarane-type diterpenes (3, 4, 5, 6), three benzochromenes (7, 8, 9) and two flavones (12, 13) exhibit a suppressive effect on contractile responses in rat thoracic aorta, among thirteen chemical constituents (1-13) isolated from the leaves. 相似文献