共查询到20条相似文献,搜索用时 15 毫秒
1.
Furukawa S Takagi N Ikeda T Ono M Nafady AM Nohara T Sugimoto H Doi S Yamada H 《Chemical & pharmaceutical bulletin》2002,50(3):439-440
Two new long-chain alkanoic acid esters of lupeol were isolated together with known triterpenoids, alpha-amyrin, beta-amyrin, cycloartenol, lanosta-7,24-diene-3beta-ol and lupeol from Alecrim-propolis collected in Brazil. The structures were characterized by spectroscopic means. 相似文献
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M. K. Mamedov 《Russian Journal of Applied Chemistry》2006,79(3):408-410
The reaction of benzene with ethylene and propylene oxides in a helium atmosphere with aluminum chloride as a catalyst and the esterification of the resulting alcohols with saturated monocarboxylic acids in the presence of the heterogeneous catalyst KU-2-8 were studied. 相似文献
4.
Katsuyuki Ogura Kunio Sanada Kazumasa Takahashi Hirotada Iida 《Tetrahedron letters》1982,23(39):4035-4038
Ethyl 2-acetylalkanoate gave ethyl 2-(methyl- or phenylthio)alkanoate in high yield on treatment wiht CH3SSO2CH3, PhSSO2Ph, or PhSSPh in the presence of small excess of EtONa in EtOH. Application of the present method to synthesis of pellitorine and the queen substance is also described. 相似文献
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A new furanodihydrobenzoxanthone, artomandin (1), together with three other flavonoid derivatives, artoindonesianin C, artonol B, and artochamin A, as well as β-sitosterol were isolated from the stem bark of Artocarpus kemando. The structures of these compounds were determined on the basis of spectral evidence. All of these compounds displayed inhibition effects to a very susceptible degree in cancer cell line tests. Compound 1 also exhibited significant antioxidant capacity in the free radical 1,1-diphenyl-2-picrylhydrazyl tests. 相似文献
7.
Protium subserratum (Burseraceae) is a neotropical tree species that is comprised of several habitat-specific ecotypes having distinct defense chemical profiles. A previously unknown triterpene, 25,30-dicarboxy-26,27,28,29-tetraacetoxy-10,11,14,15-tetrahydrosqualene, was isolated from P. subserratum young leaf tissue of one ecotype growing in Peru. The structure of 1 was determined by spectroscopic study, including 1 and 2D nuclear magnetic resonance experiments. 相似文献
8.
Shu-Pei Chang Thomas K. Miwa Ivan A. Wolff 《Journal of polymer science. Part A, Polymer chemistry》1967,5(10):2547-2556
Brassylic acid was partially esterified at 77°C. in toluene solution with ethyl, 2-methylpentyl, or nonyl alcohol and with p-toluenesulfonic acid used as catalyst. Half-esters were isolated from the respective reaction mixtures in yields of 28, 34, and 32% after reaction times of 2,6, and 8 hr. Both recovered brassylic acid and byproduct dialkyl ester were successfully used as starting materials in subsequent esterifications. Consequently, conversion of starting materials to half-ester would be increased in a process that involved continuous recycling of byproducts. Alkyl hydrogen brassylates were vinylated at 165°C. for 8 hr. with acetylene at 360 psig. The zinc salt generated in situ from zinc oxide served as catalyst and toluene as solvent. Yields were 80–88% and purities of products were 94–95%. Samples of 2-methylpentyl vinyl brassylate and nonyl vinyl brassylate of much higher purity were obtained by preparative gas–liquid chromatography or molecular distillation. Physical properties and experimental conditions for gas–liquid chromatographic analyses of both the alkyl hydrogen and alkyl vinyl brassylates are reported. 相似文献
9.
Bankeu JJ Mustafa SA Gojayev AS Lenta BD Tchamo Noungoué D Ngouela SA Asaad K Choudhary MI Prigge S Guliyev AA Nkengfack AE Tsamo E Shaiq Ali M 《Chemical & pharmaceutical bulletin》2010,58(12):1661-1665
Two new sphingolipids mucusamide (1) and mucusoside (2) have been isolated from methanol soluble part of the stem bark of Ficus mucuso WELW., together with fifteen known secondary metabolites including cellobiosylsterol (3), β-sitosterol (4), stigmasterol (5), β-sitosterol 3-O-β-D-glucopyranoside (6), lupeol acetate (7), ursolic acid (8), procatechuic acid (9), 2-methyl-5,7-dihydroxychromone 8-C-β-D-glucoside (10), apigenin (11), (-)-epicatechin (12), (+)-catechin (13), N-benzoyl-L-phenylalanilol (14), α-acetylamino-phenylpropyl α-benzoylamino-phenylpropionate (15), asperphenamate (16) and bejaminamide (17). Structures of compounds 1 and 2 were elucidated by spectroscopic analysis and chemical methods. 相似文献
10.
Caneppele D Vieira PC Dall'Oglio EL da Silva LE Sousa PT 《Natural product research》2008,22(10):846-853
The present work describes the fractionation of the crude hexane extract (EBHEX) from Calophyllum brasiliense (Clusiaceae) stem bark. Derivatization of DCM(2-9) fraction with diazomethane afforded the chromanones inophylloidic acid, isobrasiliensic acid, as well as, a mixture containing isobrasiliensic and brasiliensic acids, in the form of their more stable O-methoxy-methyl esters derivatives 1, 2, and 3, respectively. The isolation of 1 from C. brasiliense is described for the first time herein. The use of two-dimensional NMR methods ((1)H-COSY, HMQC, and HMBC) allowed the precise determination of (13)C and (1)H chemical shifts of compounds 1, 2, and 3. 相似文献
11.
E. V. Rudyakova A. N. Mirskova G. G. Levkovskaya 《Russian Journal of Organic Chemistry》2008,44(10):1517-1521
(1-Benzyl-1H-pyrrol-2-ylsulfanyl)acetic acid, 2- and 3-(1-benzyl-1H-pyrrol-2-ylsulfanyl)propionic acids, 1,1′-[1,4-phenylenebis(methylene)]bis[(1H-pyrrol-2-ylsulfanyl)acetic acid], and 1,1′-(hexane-1,6-diyl)bis-[(1H-pyrrol-2-ylsulfanyl)acetic acid] were synthesized for the first time by reactions of 1-benzyl-1H-pyrrole, 1,1′-[1,4-phenylenebis(methylene)]bis(1H-pyrrole), and 1,1′-(hexane-1,6-diyl)bis(1H-pyrrole) with thiourea, iodine, and the corresponding halogen-substituted alkanoic acids. 1-(4-Nitrophenyl)-1H-pyrrole failed to react with thiourea and iodine. 相似文献
12.
Rodrigue T. Kengap Gilbert D. W. F. Kapche Jean‐Paul Dzoyem Ingrid K. Simo Pantaleon Ambassa Louis P. Sandjo Berhanu M. Abegaz Bonaventure T. Ngadjui 《Helvetica chimica acta》2011,94(12):2231-2238
A new triterpene, conrauidienol ( 1 ), and a new dihydroflavonol, conrauiflavonol ( 2 ), along with β‐amyrin acetate ( 3 ), betulinic acid ( 4 ), ursolic acid ( 5 ), 6β‐hydroxystigmasta‐4,22‐dien‐3‐one ( 6 ), 8‐prenylapigenin ( 7 ), β‐sitosterol glucoside ( 8 ), and 3,4′,5‐trihydroxy‐6″,6″‐dimethylpyrano[2,3‐g]flavone ( 9 ) were isolated from the stem barks of Ficus conraui Warburg (Moraceae). Their structures were elucidated by spectroscopic analysis. The hexane, AcOEt, and MeOH extracts, as well as the new isolated compounds exhibited selective antimicrobial activities varying from weak to moderate. 相似文献
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Intermolecular cyclization of 1,3-dipolar aroylnitrile oxides to terminal alkynols followed by phase transfer catalyzed oxidation provided a short, convenient route to several novel (3-aroylisoxazol-5-yl)alkanoic acids. 相似文献
14.
M. A. Allakhverdiev N. A. Akperov V. M. Farzaliev B. R. Gasanov V. V. Goryachev 《Chemistry of Heterocyclic Compounds》1988,24(12):1337-1338
The reactions of some dibasic carboxylic acids with thioepichlorohydrins in the presence of interphase catalysts were studied. The first representatives of bis(thietanyl) esters of dicarboxylic acids were synthesized and characterized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1619–1620, December, 1988. 相似文献
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Cardoso-Lopes EM Maier JA da Silva MR Regasini LO Simote SY Lopes NP Pirani JR Bolzani Vda S Young MC 《Molecules (Basel, Switzerland)》2010,15(12):9205-9213
Esenbeckia leiocarpa Engl. (Rutaceae), popularly known as guarant?, goiabeira, is a native tree from Brazil. Bioactivity-guided fractionation of the ethanol stems extract afforded the isolation of six alkaloids: leiokinine A, leptomerine, kokusaginine, skimmianine, maculine and flindersiamine. All isolated compounds were tested for acetyl cholinesterase inhibition, in vitro and displayed anticholinesterasic activity. The alkaloid leptomerine showed the highest activity (IC?? = 2.5 mM), similar to that of the reference compound galanthamine (IC?? = 1.7 mM). The results showed for the first time the presence of alkaloids leptomerine and skimmianine in E. leiocarpa (Engl.) with potent anticholinesterasic activity. 相似文献
16.
T. P. Vasil'eva V. M. Bystrova M. G. Lin'kova O. V. Kil'disheva I. L. Knunyants 《Russian Chemical Bulletin》1983,32(3):556-560
Conclusions Amides of -mercapto- or -(acetylthio)alkanoic acids were obtained by the reaction of -thiolactones or -(acetylthio)alkanoic acid chlorides with amines.For Communication 2, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 616–621, March, 1983. 相似文献
17.
Torgersen T Wilkins AL Rundberget T Miles CO 《Rapid communications in mass spectrometry : RCM》2008,22(8):1127-1136
Marine algal toxins of the okadaic acid group can occur as fatty acid esters in blue mussels, and are commonly determined indirectly by transformation to their parent toxins by alkaline hydrolysis. Some data are available regarding the identity of the fatty acid esters, mainly of palmitic acid (16:0) derivatives of okadaic acid (OA), dinophysistoxin-1 (DTX1) and dinophysistoxin-2 (DTX2). Other fatty acid derivatives have been described, but with limited mass spectral data. In this paper, the mass spectral characterization of the [M-H](-) and [M+Na](+) ions of 16 fatty acid derivatives of each of OA, DTX1 and DTX2 is presented. The characteristic fragmentation of [M+Na](+) ions of OA analogues provided a useful tool for identifying these, and has not been described previously. In addition, a set of negative ion multiple reaction monitoring (MRM) methods was developed for direct determination of 16 fatty acid esters of OA, 16 fatty acid esters of DTX1 and 16 fatty acid esters of DTX2 in shellfish extracts. The MRM methods were employed to study the profiles of fatty acid esters of OA analogues in blue mussels and to compare these with fatty acid ester profiles reported for other groups of marine algal toxins. 相似文献
18.
Amandeep Singh Hayat Mohammad Mukhtar Hardeep Kaur Lakhvir Kaur 《Natural product research》2020,34(17):2514-2517
AbstractThis study emphasizes on the investigation of antiplasmodial activity of triterpenoids isolated from Ficus benjamina leaves. An unsaponified fraction of petroleum ether extract of plant leaves was subjected to silica gel column chromatography which led to the isolation of two known triterpenoids; namely ursolic acid and lupeol. These compounds were evaluated for antiplasmodial activity by schizont maturation inhibition assay using 3D7 Plasmodium strains. Both, ursolic acid and lupeol were found to exhibit significant antiplasmodial effect with an IC50 value of 18?µg/ml and 3.8?µg/ml, respectively. This study further confirms the traditional role of Ficus benjamina plant in the treatment of malaria which may be attributed to ursolic acid and lupeol. 相似文献
19.
Anodic oxidation of two series of alpha-(2)- and alpha-(4-methoxyphenoxy)alkanoic acids were studied both at the analytical and preparative scales in order to delineate mechanistic aspects of electrochemically induced spirolactonization and to develop synthetically useful orthoquinone bis- and monoketals. Although alpha-monomethylated carboxylic acids and acetic acid derivatives do not undergo any spiroannulation, alpha-dimethylated carboxylic acids furnished spirolactones in high yields. A gem-dimethyl effect is invoked to explain these differences in cyclization capacity. Electrooxidation conditions can be selected to furnish either quinone spirolactone bis- or monoketals. Chemoselective monohydrolysis of bisketals can also be accomplished in a stepwise fashion to furnish the corresponding spirolactone monoketals, but the ortho compound unfortunately dimerized in situ via a Diels-Alder process. An ECEC pathway is proposed to rationalize the observed spirolactonizations on the basis of cyclic voltammetry analyses. 相似文献
20.
V. M. Rogovik N. I. Delyagina E. I. Mysov V. F. Cherstkov S. R. Sterlin L. S. German 《Russian Chemical Bulletin》1990,39(9):1870-1876
2,3-Bis(fluorosulfato)perfluoroalkanes split under the action of CsF in the absence of solvents, giving a mixture of -fluorosulfatoperfluoro ketones, perfluoroalkene sulfates, and perfluoro -diketones. The occurrence of these reactions in solutions results mainly in the formation of oxides of the corresponding fluoroolefins or products of their conversions. The reactions carried out are the first examples of nucleophilic substitution at a secondary carbon atom in a perfluorinated saturated chain.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2057–2063, September, 1990. 相似文献