排序方式: 共有12条查询结果,搜索用时 31 毫秒
1.
Synthesis of Pyrrolophenanthridine Alkaloids Based on C(sp3)H and C(sp2)H Functionalization Reactions 下载免费PDF全文
Dr. Chihiro Tsukano Nobusuke Muto Iderbat Enkhtaivan Prof. Yoshiji Takemoto 《化学:亚洲杂志》2014,9(9):2628-2634
Assoanine, pratosine, hippadine, and dehydroanhydrolycorine belong to the pyrrolophenanthridine family of alkaloids, which are isolated from plants of the Amaryllidaceae species. Structurally, these alkaloids are characterized by a tetracyclic skeleton that contains a biaryl moiety and an indole core, and compounds belonging to this class have received considerable interest from researchers in a number of fields because of their biological properties and the challenges associated with their synthesis. Herein, a strategy for the total synthesis of these alkaloids by using C? H activation chemistry is described. The tetracyclic skeleton was constructed in a stepwise manner by C(sp3)? H functionalization followed by a Catellani reaction, including C(sp2)? H functionalization. A one‐pot reaction involving both C(sp3)? H and C(sp2)? H functionalization was also attempted. This newly developed strategy is suitable for the facile preparation of various analogues because it uses simple starting materials and does not require protecting groups. 相似文献
2.
In the course of our searching for anti-HIV agents from natural sources, we have isolated a triterpene and a doubly linked proanthocyanidin dimer as HIV-1 protease inhibitors from the wood of Xanthoceras sorbifolia Bunge (Sapindaceae)1. Further investigation of this plant has led to the isolation of a protoilludane sesquiterpene (1). The present paper describes the isolation and structural determination of this novel sesquiterpene. The EtOH eluate of a MeOH extract of the wood of X. so… 相似文献
3.
Synthesis and Application of Tetrahydro‐2H‐fluorenes by a Pd(0)‐Catalyzed Benzylic C(sp3)−H Functionalization 下载免费PDF全文
Satoshi Suetsugu Nobusuke Muto Misa Horinouchi Dr. Chihiro Tsukano Prof. Dr. Yoshiji Takemoto 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8059-8062
A new method has been developed for the synthesis of tetrahydro‐2H‐fluorenes based on a Pd(0)‐catalyzed benzylic C(sp3)?H functionalization. Importantly, the success of the cyclization step was dependent on there being substituents at the two positions ortho to the benzylic group to avoid an undesired C(sp2)?H functionalization. This method was subsequently used to prepare the right‐hand fragment of the hexacyclic triterpenoid benzohopanes, and therefore represents a powerful tool for the construction of the related compounds. 相似文献
4.
5.
6.
A novel sesquiterpene lactone was isolated from the pericarps of Illicium anisatum, a well known toxic plant in Japan, and its structure was established from spectral data and X-ray crystallographic analysis. 相似文献
7.
Chen Dandan Bu Changsheng Wang Xinye Zhang Jubing Kobayashi Nobusuke Piao Guilin Jiang Yong Feng Haoyu Dou Yuhao 《Journal of Thermal Analysis and Calorimetry》2021,143(4):3209-3220
Journal of Thermal Analysis and Calorimetry - The gasification/combustion kinetics of a typical Chinese high-ash-fusion-temperature (AFT) coal char, Huainan (HN) coal char, are analyzed using a... 相似文献
8.
Harpagometabolins Ⅰ and Ⅱ, Two New Metabolites from Harpagoside by Human Intestinal Bacteria 总被引:2,自引:0,他引:2
Xiu Wei YANG Chen Ting ZOU Masao HATTORI National Research Laboratory of Natural & Biomimetic Drugs Peking University Beijing Institute of Natural Products Toyama Medical & Pharmaceutical University Sugitani Toyama - Japan 《中国化学快报》2000,(9)
The dried roots of ScrOPhularia ningpoensl's Hemsl. (radix scrophulariae) have been usedin traditional chinese medicine for replendish the vital essence and relieve pyogenicinflammation'. Iridoids such as a harpagoside are main constitUents of radix scrophulariae2. Until noW, the pharmacological effects of these iridoids were not clearlyunderstood. Biological transformation in the human intestinal tract can induce theconversion of the iridoids to more or less biologically active compounds. … 相似文献
9.
Harpagoside,which is one main iridoid constituent of the dried roots of Scrophularia ningpoensis Hemsl.,was biotransformated by bacteria isolated from human fecal flora and three metabolites were obtained.The structures of the metabolites,including two new alkaloids,named harpagometabolins I(1)and II(2),and a known alkaloid acubinine B(3),were identified by chemi cal methods and the spectroscopic evidences. 相似文献
10.