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Polyallenes prepared with the aid of organoaluminum-VOCl3 catalysts appear to exist in three distinct phases: two crystalline phases (I and II) and an amorphous phase. Phase I shows two strong X-ray diffraction peaks at d = 5.62 Å and d = 4.04 Å; phase II has three strong peaks at d = 6.28 Å, d = 5.03 Å, and d = 4.21 Å. The band of the amorphous phase has its maximum at about d = 5.6 Å. 相似文献
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Steroidal Alkaloids from Veratrum dahuricum (Turcz.) Loes. f. with Genotoxicity on Brain Cell DNA in Mice 下载免费PDF全文
Two new steroidal alkaloids, 2β‐hydroxyverdine ( 1 ) and tomatillidine 3‐O‐β‐D ‐glucopyranoside ( 2 ), were isolated from the root and rhizome of Veratrum dahuricum (Turcz .) Loes . f., together with four known compounds, i.e., 16‐O‐(2‐methylbutyroyl)germine ( 3 ), veramitaline ( 4 ), jervine ( 5 ), and veratroylzygadenine ( 6 ). Their structures were established by extensive spectroscopic analysis, as well as by comparison with data in literature. Compounds 1 – 6 exhibited genotoxicity on brain cell DNA of the cerebellum and cerebral cortex in mice, evaluated by using single‐cell gel electrophoresis (comet assay). 相似文献
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Bioguided Isolation and Antiproliferative Activity of Constituents from Smilax korthalsii A.D.C. Leaves 下载免费PDF全文
Abdulmumeen A. Hamid Olapeju O. Aiyelaagbe Arvind S. Negi Suaib Luqman Fatima Kaneez 《中国化学会会志》2016,63(7):562-571
Ethyl acetate extract of Smilax korthalsii A.D.C. leaves exhibited antiproliferative activity on leukaemia carcinoma K562, hepatic liver cancer cells WRL and colorectal carcinoma with IC50 of 125.20, 46.10 and 160.00 μM respectively. Isolation of the bioactive ethyl acetate extract of Smilax korthalsii A.D.C. leaves gave eight compounds; 3β‐hydroxyspirost‐5‐ene (diosgenin), 1 , β‐sitosterol, 2 , lup‐5,11,20‐trien‐23‐ol, 3 , uneicos‐9‐enoic acid, 4 , ethylheptadecan‐17‐oic‐9‐enoate, 5 , cis‐octadec‐9‐enoic acid, 6 , hexadec9‐enoic acid, 7 and 11‐methyltridec‐12‐en‐1‐ol, 8 . The isolated compounds were tested against four human cancer cell lines: leukaemia carcinoma, K‐562; hepatic liver cancer cells, WRL; colorectal carcinoma, COLO; and breast carcinoma, MCF‐7 using the MTT assay. Diosgenin 1 exhibited significant antiproliferative activity against all four cell lines (IC50; K562=6.25, WRL=14.34, COLO=38.00, MCF‐7=12.40 μM), while compounds 3, 6 and 7 inhibited the growth of K‐562 at 20, 50 and 100 μM concentrations with IC50 of 90.20, 75.92 and 50.72 μM respectively. Other isolated compounds also showed cytotoxic properties against K‐562, WRL and COLO, but showed low inhibition of MCF‐7. 相似文献
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Chemical Constituents of the Endophytic Fungus Hypoxylon sp. 12F0687 Isolated from Taiwanese Ilex formosana 下载免费PDF全文
Yi‐Shuan Chen Ming‐Jen Cheng Yi Hsiao Hing‐Yuen Chan Sung‐Yuan Hsieh Chun‐Wei Chang Ta‐Wei Liu Hsun‐Shuo Chang Ih‐Sheng Chen 《Helvetica chimica acta》2015,98(8):1167-1176
Bioassay‐guided fractionation of an AcOEt‐soluble fraction of the liquid fermentation of an endophytic fungus Hypoxylon sp. BCRC 12F0687 associated with the root of Taiwanese Ilex formosana (Aquifoliaceae) resulted in the isolation of two new compounds, i.e., one benzenoid, hypoxyphenone ( 1 ), and one azaphilone derivative, hypoillexidiol ( 2 ), two metabolites isolated for the first time from natural source, (?)‐(3S)‐3‐hydroxy‐3‐methyloxindole ( 3 ) and (+)‐vermelone ( 4 ), along with twelve previously identified compounds, 5 – 16 . Their structures were determined through in‐depth spectroscopic and mass‐spectrometric analyses. The effects of some isolates on the inhibition of NO and IL‐6 production in lipopolysaccharide‐activated RAW 264.7 murine macrophages were evaluated. Of the isolates, 2 and 3 exhibited potent anti‐NO production activity, with IC50 values of 17.5±1.8 and 24.7±1.6 μM , respectively, compared to that of quercetin, an iNOS inhibitor with an IC50 value of 35.9±1.7 μM . Compounds 2, 4, 5 , and 12 also showed moderate inhibition of IL‐6 production, with IC50 values ranging from 27.2±1.8 to 35.3±5.8 μM . This is the first report on an oxindole metabolite from the genus Hypoxylon. 相似文献
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Yue Cong William Jia Jing Chen Shuang Song Jin‐Hui Wang Yu‐Hui Yang 《Helvetica chimica acta》2007,90(5):1038-1042
Two new steroidal alkaloids, neoverapatuline ( 1 ) and (1β,3α,5β)‐1,3‐dihydroxyjervanin‐12‐en‐11‐one ( 2 ), together with the four known compounds, veratramine ( 3 ), rubijervine ( 4 ), veratrosine ( 5 ), and veratroylzygadenine ( 6 ), were isolated from the roots and rhizomes of Veratrum nigrum L. Their structures were established through combined analyses of physicochemical properties and spectroscopic evidence. All compounds 1 – 6 were tested for their cytotoxicities in vitro against the human glioma cell line SF188. 相似文献
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Olapeju O. Aiyelaagbe Arvind S. Negi Abdulmumeen A. Hamid Suaib Luqman Sathish B. Kumar Fatima Kaneez 《中国化学会会志》2015,62(9):751-755
Methanol extract of Alafia barteri leaves showed cytotoxic activity on leukaemia carcinoma K562, and hepatic liver cancer cells WRL (IC50 values 193.1 and 225.0 μM respectively). Isolation of the extract gave ursane triterpenoid, 28‐acety‐urs‐5,20‐dien‐2β,3β,24α‐triol, 1 , together with undecanol, 2 , stigmasterol, 3 and octadecanoic acid, 4 . The structures of these compounds were identified by spectroscopic analysis, including MS, 1D and 2D NMR, and supported with literature data. Compound 1 exhibited cytotoxic activity against K‐562 at 50 and 100 μM concentrations with IC50 74.22 μM, while compounds 2 , 3 and 4 showed low inhibition of WRL, MCF‐7 and COLO cell lines. 相似文献
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Dehydrogenation by IBX/p‐TsOH is applied to the conversion of 3‐benzoyl propionates/propionamides to 3‐benzoyl acrylates/acrylamides in moderate to excellent yields. The reaction time for the dehydrogenation of 3‐benzoyl propionamides was remarkably shorter than that for the dehydrogenation of esters. 相似文献
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Due to the chemoselective dehalogenation by SmI2, the addition of a-halomethylsulfones to carbonyl compounds afforded ,β-hydroxysulfones. Those reactions with α-bromomethylsulfones gave the products in moderate to good yields. The SmI2-mediated addition of gem-dihalomethylsulfones to ketones also afforded α-halo-β-hydroxysulfones in moderate yields. 相似文献
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Georgia Tsolomiti 《合成通讯》2013,43(4):501-507
A simple and efficient method is described for the synthesis of new functionalized 2‐aminothiazoles, the 2‐aminothiazole‐4‐phenyl‐5‐acetamides 5, in 67–96% yields based on an application of the Hantzsch synthesis. The method involves the reaction of thiourea with 3‐benzoyl‐3‐bromo‐propionamides 4 prepared from the corresponding 3‐benzoylpropionamides 3. The tautomeric structure of the γ‐keto amides 3 and 6 is directly related to the present study, because 2‐aminothiazoles 5 are readily obtained from the corresponding open chain γ‐keto amides 3. 相似文献
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Kodakandla Venkata Syamasundar Guvvala Vinodh Kalavagunta Venkata Naga Satya Srinivas Bogineni Srinivasulu 《Helvetica chimica acta》2012,95(4):643-646
Chemical examination of the MeOH extract of Plectranthus bishopianus Benth ., a rare and endangered plant, resulted in isolation of a new abietane diterpene, 6β‐hydroxy‐7α‐methoxyroyleanone ( 1 ), along with two more diterpenoids, 6,7‐dehydroroyleanone, and 6β,7α‐dihydroxyroyleanone, a triterpene oleanolic acid, and two sterols, β‐sistosterol and stigmasterol. The structures of the isolated compounds were elucidated on the basis of spectroscopic data and also by comparison with authentic samples. 相似文献
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The previously described chiral 2‐acyloxathianes 5 (Scheme I) are used in two different enantioselective syntheses of γ‐butyrolactones. In one synthesis, Grignard addition, cleavage and reduction to carbinols RR'C(OH)CH2OH is followed by tosylation, malonate homologation, lactonization, and removal of the carbomethoxy group to give optically active γ‐lactones. A modification of this synthesis (Scheme I) leads to optically active α‐methylene‐γ‐lactones. In the second synthesis, reaction of a bromomagnesium enolate with ketones 5 leads to β‐hydroxyesters, which, by appropriate sequences of reduction and cleavage (Scheme II) are converted to optically active α‐ or β‐hydroxy‐γ‐lactones. 相似文献