首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Pectins have been isolated from five species of wild apples and have been characterized. They contain galacturonic acid, galactose, glucose, and arabinose residues. The titrimetric indices of the substances isolated have been determined. It has been shown by IR spectroscopy the pectins isolated are extracted partially in the form of pectic acids.  相似文献   

2.
Summary 1. The dioxane lignins of healthy and wilt-affected cotton plants of variety Tashkent-1 have been isolated and have been studied comparatively in relation to the vegetation period. On the basis of elementary and functional analysis, semiempirical formulas of the dioxane lignins isolated (DLCT-I to -VII) have been determined and it has been established that the dioxane lignins isolated from the wilt-affected plants contain more OCH3 groups per phenyl-propane structural unit than the lignins of healthy plants.2. The molecular-weight distributions of the dioxane lignins have been studied and it has been shown that all the dioxane lignins isolated are polydisperse, those of the affected plants to a greater degree.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 260–264, March–April, 1978.  相似文献   

3.
Chemistry of Natural Compounds - 1. C-Glycosides have been isolated from a plant of the familyScrophulariaceae for the first time. 2. Four new C-monoglycosides of apigenin have been isolated from...  相似文献   

4.
A new clerodane- and two new ent-rosane-type diterpenoids have been isolated from the New Zealand liverworts Heteroscyphus billardierii and Plagiochila deltoidea, respectively. The known bisbibenzyl compounds and acetophenones have also been isolated from Schistochila glaucescens and Plagiochila fasciculata. Their structures were established by extensive NMR techniques. Chemosystematics of the Plagiochila species have been discussed.  相似文献   

5.
Pectins have been isolated from five species of wild apples and have been characterized. They contain galacturonic acid, galactose, glucose, and arabinose residues. The titrimetric indices of the substances isolated have been determined. It has been shown by IR spectroscopy the pectins isolated are extracted partially in the form of pectic acids.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbekistan Republic, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 355–357, May–June, 1993.  相似文献   

6.
Recently many bioactive indole alkaloids have been isolated from marine organisms. Many of them have novel ring systems which are not found in the indole alkaloids isolated from higher plants and molds on the land. We have chosen β-carboline alkaloids, eudistomins and manzamines, as targets for total synthesis.  相似文献   

7.
Reversed-phase and normal-phase variants of microcolumn high-performance liquid chromatograph (HPLC) for the separation of the preparation Teféstrol, isolated from the roots ofFerula tenuisecta have been developed. Minor components have been isolated. The amounts of the major and minor components in Tefestrol have been determined.  相似文献   

8.
New naturally occurring nitrogenous compounds 1 and 2, along with a new dimeric lignan glucoside 3, have been isolated from the ethyl acetate soluble fraction of Centaurea iberica. Their structures have been elucidated through spectroscopic techniques. All the isolated compounds showed significant platelet aggregation inhibition.  相似文献   

9.
Four alkaloids were isolated from Anisocyclea grandidieri (Fam. Menispermaceae). Trilobine and stebisimine have already been found in other menispermaceous plants, whereas (?)-epistephanine and 12′-O-desmethyltrilobine have not been isolated before.  相似文献   

10.
Several new K and Hg(II) complexes derived from crown ethers (DC18C6, DB18C6) have been prepared by tribochemistry reactions. The isolated solid complexes have been characterized by I.R. spectral measurements. The isolated solid complexes are compared with the corresponding metal complexes prepared in solution. Also, the IR and NMR spectra of the solid complexes have been used to determine the strength of bond between Hg(II) ion and the crown ether.  相似文献   

11.
The new 2(S)-2′,5-dihydroxy-7-β-D-glucopyranosyloxyflavanone has been isolated from the epigeal part ofScutellaria ramosissima M. Pop. Oroxylin A, woganin, 2′,6′-trihydroxy-6,7,8-trimethoxyflavone, and vanillic and syringic acids, and also the new substance 5,6-dihydroxy-7,8-dimethoxyflavone, have been isolated from the roots of this plant for the first time. The structures of the flavonoids isolated have been established on the basis of chemical transformations and spectral characteristics.  相似文献   

12.
Twenty-five pure environmentally relevant toxaphene components have been isolated from photochemically modified technical toxaphene by means of a combination of column chromatography on silica gel and preparative high resolution liquid chromatography. These compounds are 6 chlorinated camphenes (1–3, 5, 7, and 11) and 19 chlorinated bornanes (4, 6, 8–10, 12–16, 18–24, 26, and 27 according to Table 1). Two further chlorobornanes (17 and 25) have been isolated from a highly chlorinated mixture obtained by the excess chlorination of 2-exo,10-dichlorobornane. The structural elucidation of the isolated compounds has been carried out with spectroscopical methods.  相似文献   

13.
《Tetrahedron》2004,60(1):159-164
Three new sesquiterpenoids bearing sulfurated ester groups have been isolated from the roots of Thapsia villosa L. Their structures have been elucidated by spectroscopic means. This is the first time that a methylthiopropionic acid ester is isolated from natural sources.  相似文献   

14.
Cortical granules are secretory vesicles bound to the inner surface of the plasma membrane of sea urchin eggs. Intact granules can be isolated by shearing away the cytoplasm of eggs which have been bonded to a protamine-coated surface. When Ca2+ is added to preparations of isolated granules the granules fuse with each other and release their contents. It is believed that isolated cortical granules may be an excellent model system for the biochemical study of exocytosis.  相似文献   

15.
Methods of alkylation of α-, β- and γ-cyclodextrins have been optimized with regard to the parameters of reaction, degree of alkylation and yields. The analysis of the reaction mixtures and of the isolated single species has been performed by high temperature GC and HPLC. The phase systems of the preferably applied HPLC have been carefully adjusted by variation of both the stationary and mobile phases to the very different hydrophobicities of the various alkylated CD species which have been synthesized. Several partially or fully alkylated CD species were isolated from preparative scale HPLC separations in high purity.  相似文献   

16.
The alkaloids of the epigeal part and roots ofCorydalis stricta have been studied. Of the 23 alkaloids isolated, N-methylcorypalline proved to be new, and its structure has been determined. Stilopine hydroxymethylate and pycnarrhine have been isolated from the genusCorydalis for the first time, and cheilanthiofoline isocorypalmine, scoulerine, isoboldine, reticuline, N-methylcoclaurine, coreximine, juziphine, pancorydine, corypalline, wilsonirine, stilopine, adlumidine, dihydrosanguinarine, adlumine, and bicucculine have been isolated from this species of plant for the first time.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 490–493, July–August, 1983.  相似文献   

17.
Six flavanones have been isolated for the first time from Siberian tansy, and two of them have proved to be new compounds.  相似文献   

18.
The coumarin composition of the epigeal part ofStellera chamaejasme has been studied. Together with the known coumarins daphnoretin, daphnetin, daphnin, and daphnorin, we have isolated the new bicoumarin glycoside chamaejasmoside and have established its structure by chemical transformations and a study of its spectral properties. Of the known coumarins, this is the first time that daphnorin and daphnin have been isolated from this plant. Deceased.  相似文献   

19.
蓝翠雀花(Delphinium caeruleum Jacq.ex Camb.)~[1]在甘肃西南部、西藏、青海等地分布较广,藏民常用其治疗牙痛、跌打损伤.其化学成分迄今未见报道.我们将其全草用乙醇浸泡,石油醚脱脂,乙醚除去色素,酸碱常法处理,氯仿萃取得总生物碱.用氧化铝、硅胶进行多次柱层析及硅胶薄层制备层析,分得碱(1)~(4).  相似文献   

20.
We report the isolation and characterization of bis- and tris-adducts of fulleropyrrolidine derivatives. First, all eight N-methyl regioisomers with two addends on the C60 sphere have been isolated; second, C60 was used as starting material for the synthesis of tris-adducts, and the products formed in detectable quantities have been isolated and characterized. Third, the same compounds were obtained by introducing the third addend on each previously isolated bis-derivative: this approach facilitated the assignment of the relative geometry through chromatographic comparison of the diverse reaction mixtures. Finally, the obtained tris-adducts have been characterized by means of ES-MS, UV-vis, 1H NMR, as well as comparison with UV spectra and elution order of Bingel and Diels-Alder tris-adducts described in the literature.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号