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1.
Gmeliniin A, a new pentacyclic triterpene of ursane series isolated from the aerial parts of Echinops gmelinii, is elucidated structurally as 1 on the basis of 1D and 2D NMR spectroscopic studies. 相似文献
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Summary The structure of a previously unknown pentacyclic triterpene isolated fromCentaurea squarrosa Willd. has been established. It is urs-20(3)-en-3-ol (I).A. L. Mndzhoyan Institute of Fine Organic Chemistry, Academy of Sciences of the Armeniam SSR, Erevan. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 59–69, January–February, 1977. 相似文献
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Two new and one known compounds were isolated from the methanol extract of Sesamum indicum leaves. By means of spectroscopic methods, their structures were elucidated and identified to be 3-epibartogenic acid (1), kaempferol 3-O-[2-O-(trans-p-coumaroyl)-3-O-α-L-rhamnopyranosyl]-β-d-glucopyranoside (2) and epigallocatechin (3). Compound 1 and 3 strongly inhibited α-amylase with the IC50 values of 146.7 and 303.9 μM, respectively, in comparison with acarbose (IC50 124.0 μM). 相似文献
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Alécio Antonio Pimenta Jr. Sílvia Ribeiro de Souza e Silva Grácia Divina de Fátima Silva Luiz Cláudio de Almeida Barbosa Javier Ellena Antonio Carlos Doriguetto 《Structural chemistry》2006,17(1):149-153
A pentacyclic triterpene, 3β,30-dihydroxy-lup-20(29)-ene, was isolated from the powder extract of Maytenus imbricata. The structure and stereochemistry of the compound were established by spectroscopic techniques and unambiguously determined by single crystal X-ray crystallography. The crystal structure shows one molecule in the asymmetric unit. The crystal packing is stabilized by O–H···O intermolecular hydrogen bonds, which give rise to infinite helical chains along the c unit cell axis. The intra-molecular geometry was analyzed using MOGUL, a knowledge base of molecular geometry derived from the Cambridge Structural Database (CSD). 相似文献
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A new pentacyclic cucurbitane glucoside and a new triterpene from the fruits of Gymnopetalum integrifolium 总被引:1,自引:0,他引:1
Sekine T Kurihara H Waku M Ikegami F Ruangrungsi N 《Chemical & pharmaceutical bulletin》2002,50(5):645-648
A new pentacyclic cucurbitane glucoside, named aoibaclyin (1) and a new triterpene (2) have been isolated from the EtOH extract of the fruits of Gymnopetalum integrifolium Kurz (Cucurbitaceae), together with three known compounds, bryoamaride (3), 25-O-acetylbryoamaride (4) and beta-sitosterol 3-O-beta-D-glucopyranoside (5). The structures of these compounds were elucidated by spectroscopic analyses. 相似文献
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Giuliana Severini Ricca Bruno Danieli Giovanni Palmisano Helmut Duddeck M. Hani A. Elgamal 《Magnetic resonance in chemistry : MRC》1978,11(4):163-166
The 13C NMR spectra of some pentacyclic triterpenoids, 3β-acetoxy-11-oxo-olean-12-ene-30-oic acid methyl ester, 3β-acetoxy-11-oxo-olean-12-ene-29-oic acid methyl ester, the corresponding 11-desoxo methyl esters, 3β-acetoxy-11-oxo-18α-olean-12-en-30-oic acid methyl ester and 3β-acetoxy-11-oxo-18α-olean-12-en-29-oic acid methyl ester are discussed. The shielding data are interpreted in term of the different orientation of the carbomethoxy group and of the change in configuration at the D/E ring junction and are diagnostically valuable for the differentiation of the mentioned compounds. 相似文献
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从玉柏石松中分得三个新的△^1^4-serratene型的五环三萜酯(1-3), 根据其理化性质和波谱数据, 运用二维核磁共振新技术异核远程相关谱(HMBC), 证明1为16-oxo-lyclanitin-30-yl-p-coumarate, 2为16-oxo-diepilycocryptol-30-yl-p-coumarate, 3为diepilycocryptol-30-yl-p-coumarate, 并指定了1中所有碳和氢、2和3中所有碳和部分氢的NMR信号的归属。 相似文献
9.
Hideyuki Shigemori Kazusei Komatsu Yuzuru Mikamia Junichi Kobayashi 《Tetrahedron》1999,55(52):2297-14930
A new anthracycline-derived pentacyclic metabolite, seragakinone A (1), was isolated from the mycelium of an unidentified fungus, which was separated from the Okinawan marine rhodophyta Ceralodictyon spongiosum, and the structure was elucidated by spectroscopic data. 相似文献
10.
Six new triterpene saponins bearing an oxygen bridge between C-13 and C-28 and with pronounced anti-leishmanial activity were isolated from the methanolic extract of leaves of the Vietnamese medicinal plant Maesa balansae. The structure was established on the basis of detailed NMR (COSY, NOESY, HMQC, HMBC, TOCSY and DEPT) and FAB-MS studies along with chemical degradation. All saponins identified contained the same pentaglycosidic side chain, but a different esterification pattern on the triterpenoid part. Biological evaluation of the individual compounds against visceral leishmaniasis (Leishmania infantum amastigotes) revealed a much better activity in vitro compared to the reference compound Pentostam®, which is currently used as first-line treatment for leishmaniasis. 相似文献
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A new pentacyclic triterpene, named ursethoxy acid (1) was isolated from the aerial parts of Lantana camara Linn. Its structure has been elucidated as 3,25-epoxy-3alpha-ethoxy-urs-12-en-28-oic acid through extensive 1D- and 2D-NMR (COSY-45, NOESY, J-resolved, HMQC and HMBC) studies. 相似文献
13.
L. Jurd 《Tetrahedron letters》1976,17(21):1741-1744
14.
David Lontsi B. Lucas Sondengam J. Foyere Ayafor Joseph D. Connolly 《Tetrahedron letters》1987,28(52)
From the methylated polar extract of stem bark of
(Cecropiaceae) a novel triterpenic A-ring seco derivative has been obtained and the structure elucidated by spectroscopic methods. 相似文献
15.
Pfrang C Martin RS Nalty A Waring R Canosa-Mas CE Wayne RP 《Physical chemistry chemical physics : PCCP》2005,7(12):2506-2512
Rate coefficients for reactions of nitrate radicals (NO3) with (Z)-pent-2-ene, (E)-pent-2-ene, (Z)-hex-2-ene, (E)-hex-2-ene, (Z)-hex-3-ene, (E)-hex-3-ene and (E)-3-methylpent-2-ene were determined to be (6.55 +/- 0.78)x 10(-13) cm3 molecule(-1) s(-1), (3.78 +/- 0.45)x 10(-13) cm3 molecule(-1) s(-1), (5.30 +/- 0.73)x 10(-13) cm(3) molecule(-1) s(-1), (3.83 +/- 0.47)x 10(-13) cm(3) molecule(-1) s(-1), (4.37 +/- 0.49)x 10(-13) cm(3) molecule(-1) s(-1), (3.61 +/- 0.40)x 10(-13) cm3 molecule(-1) s(-1) and (8.9 +/- 1.5)x 10(-12) cm3 molecule(-1) s(-1), respectively. We performed kinetic experiments at room temperature and atmospheric pressure using a relative-rate technique with GC-FID analysis. The experimental results demonstrate a surprisingly large cis-trans(Z-E) effect, particularly in the case of the pent-2-enes, where the ratio of rate coefficients is ca. 1.7. Rate coefficients are discussed in terms of electronic and steric influences, and our results give some insight into the effects of chain length and position of the double bond on the reaction of NO3 with unsaturated hydrocarbons. Atmospheric lifetimes were calculated with respect to important oxidants in the troposphere for the alkenes studied, and NO3-initiated oxidation is found to be the dominant degradation route for (Z)-pent-2-ene, (Z)-hex-3-ene and (E)-3-methylpent-2-ene. 相似文献
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Citrinadin A, a novel pentacyclic alkaloid from marine-derived fungus Penicillium citrinum 总被引:4,自引:0,他引:4
Tsuda M Kasai Y Komatsu K Sone T Tanaka M Mikami Y Kobayashi J 《Organic letters》2004,6(18):3087-3089
[structure: see text] A novel pentacyclic alkaloid, citrinadin A (1), was isolated from the cultured broth of the fungus Penicillium citrinum, which was separated from a marine red alga, and the structure was elucidated by spectroscopic data. The relative stereochemistry of the pentacyclic core was assigned on the basis of NOESY data and (1)H-(1)H coupling constants, and the presence of an N,N-dimethyl-L-valine residue in 1 was determined by chiral HPLC analysis of the hydrolysate. 相似文献
19.
An azaanalog of adamantene, 2-azaadamant-1-ene () and 4-azaprotoadamant-3-ene () were generated in the nonstatistical ratio via photolysis of 3-azidonoradamantane (). The highly strained and could not be isolable but were trapped by MeOH. Acidolysis of was also reported, and discussed in comparison with the photolysis. 相似文献
20.
The saponin from the berries of Phytolacca americana yielded one known and two new aglycones. One of the new aglycones was identified as desmethylphytolaccagenin 2, and the other as 3β, 23-dihydroxyolean-12-ene-28, 30-dioic acid-30-methyl ester 3. 相似文献