共查询到20条相似文献,搜索用时 15 毫秒
1.
Xiao Mei LI Ying Hong WANG Mao LIN* Institute of Materia Medica Chinese Academy of Medical Sciences Perking Union Medical College Beijing 《中国化学快报》2001,(7)
Continuous investigation on stilbenoids from the lianas of Gnetum pendulum1 resulted in the isolation of a new dimer, Gnetupendin C (1), a cis-2, 3-dihydrobenzofuran dimer of resveratrol and oxyresveratrol.Gnetupendin C (1) was obtained as yellowish amorphous power, [(] -220.0 (c 0.100, MeOH). UV (c 0.02, MeOH) (max (log (): 222 (4.5), 288 (sh), 310 (sh), 327 (4.4) nm. The high resolution EIMS, m/z 470.1344, agreed with a molecular formula of C28H22O7 (requires 470.1366) and the 1H NM… 相似文献
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A Pair of Dimeric Stilbene Epimers from Gnetum Montanum 总被引:1,自引:0,他引:1
GnetummontanumofgnetaceaisdistributedinsouthernChina.AsaChinesefOlkmedicine,itslianasareusedtotreatbronchitisandarthritis'.Previousinvestigationofthisspeciesledtotheisolationofsomealkaloidsanddibenzyletherde,i.ati.es2.lnourstudies,tenknowncomponentsincludingresveratrol,isohapontigenin,daucosterol,6-sitosterol,stearicacid,gnetifolinE,gnetol,isorhapontigenin-3-O-6-glucopyra(-)E-viniferinandgnetifolinCwereisolatedfromthesameresource.Atthesametime,apairoftraceepimerswereobtained.Thisisthefirste… 相似文献
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Ying Hong WANG Kai Sheng HUANG Mao LIN* Institute of Materia Medica Chinese Academy of Medical Sciences Peking Union Medical College Beijing 《中国化学快报》2000,11(12)
Continuous investigation on oligostilbenes from the lianas of Gnetum hainanense resulted in the isolation of a new rhapontigenin dimer, Gnetuhainin P (1), in addition to the dimers of resveratrol and oxyresveratrol reported previously1. Gnetuhainin P (1) was obtained as a yellowish amorphous powder, [(]25D +6.6 (c 0.092, MeOH). The high resolution FABMS m/z 533.1866 [M+H]+ gave a molecular formula of C30H28O9 (C30H29O9 requires 533.1812), which corresponds to a isorhapontigenin dimer. … 相似文献
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Three new resveratrol oligomers, hopeahainanphenol ( 1 ), neohopeaphenol A ( 2 ), and neoisohopeaphenol A ( 3 ), were isolated from the stem bark of Hopea hainanensis (Dipterocarpaceae). Their structures were elucidated by in‐depth spectroscopic analyses, including 1D‐ and 2D‐NMR techniques, and by HR‐ESI‐MS. All the three phytochemicals were tested in vitro for acetylcholinesterase (AChE) inhibitory and antitumor activity. The dimeric compound 2 , which corresponds to (1S*,6S*,7S*,11bS*)‐1,6,7,11b‐tetrahydro‐1,7‐bis(4‐hydroxyphenyl)‐6‐[(1R*,6R*,7R*,11bR*)‐1,6,7,11b‐tetrahydro‐4,8,10‐trihydroxy‐1,7‐bis(4‐hydroxyphenyl)benzo[6,7]cyclohepta[1,2,3‐cd]benzofuran‐6‐yl]benzo[6,7]cyclohepta[1,2,3‐cd]benzofuran‐4,8,10‐triol, was found to be significantly active against AChE, with an IC50 value of 7.66 ± 0.13 μm. 相似文献
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Yiming Hu Yoshinori Saito Yosuke Matsuo Xun Gong Takashi Tanaka 《Molecules (Basel, Switzerland)》2022,27(24)
The chemical constituents of two root samples of Eupatorium heterophyllum DC. collected in Yunnan Province, China, were investigated. Five new oligomeric benzofurans (1–5), nine new benzofuran/dihydrobenzofuran derivatives, and a new thymol analog were isolated, and their structures were determined using extensive spectroscopic techniques, such as 1D and 2D NMR spectroscopy and DFT calculations of the CD spectra. Most of the new compounds, including oligomeric benzofurans (1–5), were obtained from only one of the root samples. Furthermore, this is the first example that produces oligomeric benzofurans in this plant. These results imply that diversification of secondary metabolites in E. heterophyllum is ongoing. Plausible biosynthetic pathways for 1–5 are also proposed. 相似文献
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Stilbenoids in lianas of Gnetum parvifolium. 总被引:2,自引:0,他引:2
T Tanaka I Iliya T Ito M Furusawa K I Nakaya M Iinuma Y Shirataki N Matsuura M Ubukata J Murata F Simozono K Hirai 《Chemical & pharmaceutical bulletin》2001,49(7):858-862
Five new stilbene dimers were isolated from the lianas of Gnetum parvifolium in addition to known stilbenoids. The structures of the compounds were established on the basis of spectroscopic evidence, including long-range coupling and nuclear Overhauser effect experiments, in NMR spectrum. Among the isolates, 2b-hydroxyampelopsin F showed potent inhibitory activity in the Maillard reaction. 相似文献
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Tetsuro Ito Zulfiqar Ali Ibrahim Iliya Miyuki Furusawa Toshiyuki Tanaka Ken‐ichi Nakaya Yoshikazu Takahashi Ryuichi Sawa Jin Murata Dedy Darnaedi Munekazu Iinuma 《Helvetica chimica acta》2005,88(1):23-34
Four new stilbene glucosides, upunosides A ( 1 ), B ( 5 ), C ( 6 ), and D ( 7 ), were isolated from the stem of Upuna borneensis (Dipterocarpaceae) together with the three known glucosides 3, 4 , and 8 . Upunoside A ( 1 ) is the first natural instance of a glucoside of a resveratrol pentamer, and its aglycone has a dibenzo‐fused bicyclo[5.3.0]octadiene and two dihydrobenzofuran moieties. The relative structure of the aglycone was determined by spectral analysis including 1D and 2D NMR experiments. 相似文献
11.
Currently there is an intense interest in developing unnatural folding oligomers and polymers that may mimic or rival natural proteins[1]. Most of the efforts in this field have been focused on designing helical structures that mimic the natural α-helix[2], the best understood protein secondary structure. 相似文献
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A new nortriterpene, 2‐hydroxy‐3‐methyl‐21‐oxo‐12,24‐dinor‐D : B‐friedooleana‐1,3,5(10),7‐tetraen‐29‐oic acid ( 1 ), was isolated from the root of Celastrus hypoleucus, together with the two known compounds, celastorol ( 2 ) and pristimerine ( 3 ). Their structures were elucidated on the basis of spectroscopic analyses. Compounds 1 – 3 exhibited in vitro significant antioxidant (against lipid peroxidation; by the TBARS method) and antitumor activities (against cancer cell lines P‐388, A‐549, HL‐60, and BEL‐7402). 相似文献
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Three Stilbene Tetramers from the Roots of Caragana sinica 总被引:3,自引:0,他引:3
Three stilbene tetramers, carasinols A-C (1-3), along with three known substances, leachianol C, cararosinol A and stenophyllol B, were isolated from the roots of Caragana sinica. Their structures were elucidated by spectroscopy. It was found that compounds isolated except for stenophyllol B stimulated the proliferation of cultured osteoblasts. 相似文献
16.
Jian‐Chao Chen Xiao‐Xi Yuan Lin Zhou Jie‐Qing Liu Yin Nian Zhong‐Rong Li Yan Li Ming‐Jin Xie Ming‐Hua Qiu 《Helvetica chimica acta》2014,97(11):1546-1554
Four new 5β,19‐epoxycucurbitacins, kuguacins T–W ( 1 – 4 , resp.), along with nine known cucurbitane derivatives, 5 – 13 , were obtained from the fresh fruit of Momordica chrantia. Structures of the new metabolites were elucidated as 5β,19‐epoxy‐25‐hydroxycucurbitane‐3,7,23‐trione ( 1 ), 5β,19‐epoxy‐3,7‐dioxo‐23,24,25,26,27‐pentanorcucurbitan‐22‐oic acid ( 2 ), 5β,19‐epoxy‐3β‐hydroxycucurbit‐24‐ene‐7,23‐dione ( 3 ), and 5β,19‐epoxy‐25‐hydroxycucurbit‐23‐ene‐3,7‐dione ( 4 ), by extensive spectroscopic investigations, which were confirmed by a single‐crystal X‐ray diffraction analyses in the case of compound 4 . 相似文献
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Sheng Hong LI Hong Jie ZHANG* Ping YAO Han Dong SUN Phytochemistry Laboratory Kunming Institute of Botany Academia Sinica Kunming Guizhou Institute of Traditional Chinese Medicine Guiyang 《中国化学快报》2001,(1)
The ongoing study of our previous work1-4 led to the isolation of four new taxoids from the barks of Taxus yunnanensis. One of them belonged to a paclitaxel analogue named 7-xylosyl-taxol D, the others were 11(15?1)-abeotaxoids with an opened D-ring system, named taxuyunnanines P-R respectively. Their structures were determined by means of spectral method s including 1D and 2D NMR spectroscopy.7-Xylosyl-taxol D (1), white powder, has a molecular formula, C49H61NO18, from its positive HR… 相似文献
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The purpose of this work is to provide an in‐depth interpretation of the optical and electronic properties of a series of aromatic oligomers and polymers, including [N‐(4‐(5‐(3‐(1,3,4‐oxadiazol‐2,5‐ylene)phenyl)‐1,3,4‐oxadiazol‐2‐ylene)phenyl)‐N‐(1,4‐phenylene)amine]n (NPPP)n and [N‐(4‐(5‐(3‐(1,3,4‐oxadiazol‐2,5‐ylene)phenyl)‐1,3,4‐oxa‐diazol‐2‐ylene)phenyl)‐N‐(1,4‐phenylene)naphthalene‐1‐amine]n (NPPN)n (n=1–4). These polymers and oligomers show great potential for application to organic light‐emitting diodes (OLEDs) as efficient blue emitters due to the tuning of the optical and electronic properties. The geometric and electronic structures of the oligomers in the ground state were investigated using density functional theory (DFT) and the ab initio HF, whereas the lowest singlet excited state of NPPP1 was optimized with ab initio configuration interaction singles (CIS). To assign the absorption and emission peaks observed in the experiment, the absorption and emission spectra of the ground and lowest singlet excited states were calculated with time‐dependent DFT (TD‐DFT) and Zerner's independent neglect of differential overlap (ZINDO). All DFT calculations were performed using the B3LYP functional and the 6‐31G basis set. The results show that the HOMO, LUMO, energy gaps, ionization potentials, and electron affinities for these polymers are affected by increasing the conjugated chain, which favors the hole and electron injection into OLED. The trend of the variation of ΔH‐L and the lowest excitation energies with 1/n, and the electronic structure and optical properties of these polymers were extrapolated and analyzed. The absorption spectra exhibit red shifts to some extent [the absorption spectra: 359.47 (NPPP1)<370.84 (NPPP2)<373.84 (NPPP3)<375.33 nm (NPPP4); 361.14 (NPPN1)<370.34 (NPPN2)<373.39 (NPPN3)<374.62 nm (NPPN4)]. Our calculated spectra agree well with the experimental findings where available, showing small but systematic deviations. 相似文献
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O. Mukbaniani G. Zaikov T. Tatrishvili G. Titvinidze N. Mukbaniani 《Macromolecular Symposia》2007,247(1):364-370
The dehydrocondensation reactions of α,ω–bis(trimethylsiloxy)methylhydridesiloxane with saturated primary n-alcohols in the presence of anhydrous powder-like potassium hydroxide or platinum on the carbon (Pt/C-5%) at 1:30 ratio of initial compounds, at various temperature (40–60 °C) was carried out, and methylsiloxane oligomers with n-alkyloxy substituted groups in the side chain were obtained. It was shown that completely dehydrocondensation of all active Si H groups do not take place. Dehydrocondensation reaction order, activation energy and rate constants were found. The synthesized oligomers were characterized by 1H, 13C NMR, Cosy and FTIR spectra data. Gel-permeation chromatography, differential scanning calorimetric, thermogravimetric and wide-angle X-ray investigations of synthesized oligomers were carried out. 相似文献
20.
WanShengCHEN ZhaoYangTAO WeiDongZHANG LianNaSUN 《中国化学快报》2003,14(7):711-712
Neo-przewaquinone A was isolated from the root of Salvia przewalskii Maxim. The structure elucidation and ^1H, ^13C NMR assignments were achieved by spectroscopic method. 相似文献