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51.
《Analytical letters》2012,45(9):735-739
Abstract A comparison of different silylating agents was conducted by gas-chromatography, using methandienon e(17α-methyl-androsta-1, 4-dien-17β-ol-3-one) as a model substance for steroids with hindered hydroxyl groups. A very significant catalytic effect of methoxy-amine on the reactions was found with all examined silylating agents. A 100% yield was found using N-trimethylsilyl-imidazole in combination with the catalyst in an “on-column” reaction. 相似文献
52.
53.
Deculsnea./al..gesiiFranch.IsatraditionalChinesemedicinalplantwidely'distributedinChina.usedasananti-rheumaticandalltitussivedrugforalongtimeinChinesefolkmedicine'.Itsmethanolextractshowedantitunlouracidityif71)if)oagainstS:sl},HepaandEhrlichcellsanditsphytochemicalstudiesonsaponinshasreported'.Asacontinuationofthestudiesonthisplant,wepresentthespectralandchemicalevidenceofthestructureofanewdecaisosideF.Thedriedstems(2.23kg)werepercolated\vith95%EtOH.Afterremovalofthepercolatesb}evaporat… 相似文献
54.
A. A. Kicha N. V. Ivanchina A. I. Kalinovskii P. S. Dmitrenok E. V. Sokolova I. G. Agafonova 《Chemistry of Natural Compounds》2007,43(1):76-80
Five sulfated steriodal compounds including one new glycoside called linckoside L7 (1) and four previously known glycosides
2–5 were isolated from the starfish Linckia laevigata. The structure sodium (22E, 24R)-3-O-(2-O-methyl-β-D-xylopyranosyl)-29-O-(β-D-xylopyranosyl)-24-ethylcholest-4,22-dien-3β,6β,8,15α,16β,29-hexaol 15-O-sulfate was proposed for L7. Linckoside L7 inhibited fertilization and egg-cell development in the sea urchin Strongylocentrotus intermedius.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 64–67, January–February, 2007. 相似文献
55.
56.
《Magnetic resonance in chemistry : MRC》2002,40(9):618-621
The assignments of 1H and 13C NMR spectra for three new triterpene saponins from Silene vulgaris (gypsogenin 3‐O‐glucuronide, quillaic acid 3‐O‐glucuronide, and gypsogenin 3‐O‐glycoside) are reported. In addition to 1D NMR methods, 2D NMR techniques (COSY, HSQC, HMBC, and HSQC‐TOCSY) were used for the assignments. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
57.
Stanley E. Ukwueze Patience O. Osadebe Festus B.C. Okoye 《Natural product research》2015,29(18):1728-1734
Bioactivity-guided fractionation of methanol extract from the leaves of Psidium guajava L. (Myrtaceae) yielded a new benzophenone glycoside, Guajaphenone A (2) together with two known compounds, Garcimangosone D (1) and Guaijaverin (3). Their structures were elucidated by analysis of spectroscopic data including 1D and 2D NMR and electrospray ionisation mass spectrometry (ESI-MS). The isolated compounds were screened against standard strains of Gram-positive and Gram-negative bacteria using broth dilution assay method, and the MIC values determined and compared with reference antibiotic ceftriaxone. They were found to have significant antibacterial activities against Escherichia coli and Staphylococcus aureus with all of them showing better activities against S. aureus, but displaying weaker activities, in comparison to ceftriaxone. However, despite reduced effect of these compounds against the organisms, this work opens the perspective to use these molecules as ‘leads’ for the design of novel and selective drug candidates for some tropical infectious diseases. 相似文献
58.
A new 19-oxygenated steroid, 25-acetate-nebrosteroid K (1), and five known steroids (2–6), along with one known 19-hydroxy steroidal glycoside (7) were obtained from the gorgonian Dichotella gemmacea collected from the South China Sea. The structure and relative configuration of 1 were elucidated by using comprehensive spectroscopic data including NOESY spectra. Compound 1 represents the first example of 19-oxygenated steroid with a 19-oic acid methyl ester group isolated from gorgonians. All of the isolated compounds were evaluated for lethal activity to brine shrimp Artemia salina and cytotoxicity against A549 and HL-60 cell lines. Among them, 1 showed strong lethality towards A. salina. 相似文献
59.
A novel triterpenoid 3α,16β,23,24-tetrahydroxy-28-nor-ursane-12,17,19,21-tetraen (1) was isolated from the fruits of Gardenia jasminoides var. radicans Makino. The structure of the new compounds was elucidated on the basis of spectroscopic analysis including MS and NMR data. Compound 1 was in vitro tested for cytostatic activity on human throat cancer (Hep-2) cell line by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide method and showed mild anticancer activity with the IC50 of 31.2 μM. 相似文献
60.
Yan-Ni Shi Lian Yang Jin-Hua Zhao Yi-Ming Shi Yan Qu Hong-Tao Zhu 《Natural product research》2015,29(14):1372-1375
Fifteen known compounds including four triterpenoids (1–4), one sterol (5), one diketopiperazine alkaloid (6) and nine phenolics (7–15) were isolated from the stems of Piper wallichii. Their structures were elucidated by means of spectroscopic analysis, and acidic hydrolysis in case of the 2-oxo-3β,19α,23-trihydroxyurs-12-en-28-oic acid β-D-glucopyranosyl ester (1). The structure of compound 1 was fully assigned by 1D and 2D NMR experiments for the first time. All isolates were tested for their antibacterial, antifungal, anti-inflammatory and antiplatelet aggregation bioactivities. 相似文献