首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 93 毫秒
1.
    
The isomerization of 5-vinyl-2-norbornene (1) has been studied in the presence of Co (R1-COCHCOR2)x–Et6–yAl2Cly (x=2, 3; y=2–4) catalytic systems. Co(acac)2–AlEt3 and Co(acac)3–AlEt3 systems isomerize1 to 5-ethylidene-2-norbornene (2), whereas the Co(PhCOCHCOPh)2–AlEt3 system selectively forms 3-vinylnortricyclene (3).2 is always accompanied by formation of ethylidene norbornane (4). A possible mechanism for formation of products is proposed.  相似文献   

2.
The composition of the fatty mono- and dihydroxy acids of the fruit ofRumex paulsenianus Rech. fil. (familyPolygonaceae) has been determined by a combination of IRS, UVS, GLC, and mass-spectrometric methods. (22) Monohydroxy acids of the C14–C20 series, including isomers and isologues, and four dihydroxy acids from C18 to C20, including a new isomeric 9-OH-10, 12–17:2 acid have been detected.Institute of the Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 762–765, November–December, 1991.  相似文献   

3.
Summary From the neutral fraction of an acetone extract of the roots of plants of the genusFerula,F. gummosa Boiss.,F. pseudoreoselinum Rgl. et Schmalh. (K-Pol.) andF. Samarkandica Eug. Kor., we have isolated a coumarin gummosin with the composition C24H30O4, mp 176–177°C, [a]D –54°C. The structure of gummosin corresponds to formula (III).With respect to structure, gummosin is a spatial isomer of farnesiferol A; it differs from the latter by the fact that the secondary OH group in gummosin is axial.Khimiya Prirodynkh Soedinenii, Vol. 2, No. 6, pp. 383–387, 1966  相似文献   

4.
Summary The leaves ofFraxinus mandschurica Rupr. and the bark ofF. potamophila Herd. have yielded esculetin, fraxinol, and a new coumarin C10H8O5, mp 228–230°C which we have called isofraxetin. On the basis of NMR and UV spectroscopy it has been established that isofraxetin is 5,7-dihydroxy-7-methoxycoumarin.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Institute of Chemistry, Academy of Sciences of the Turkmen SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 493–497, July–August, 1973.  相似文献   

5.
29Si NMR peaks due to species with the double four-membered ring siloxane backbone composed of both Si(O)4/2 and CH3Si(O)3/2 units, (CH3) n Si8O 20 – n /(8 – n) – (n=1–3), formed by co-hydrolysis of tetraethoxysilane and methyltriethoxysilane in the presence of tetramethylammonium ions in methanol have been assigned. It has been found that 29Si NMR peaks due to Si(OSi)3(O) units shift to lower frequencies by replacement of the adjacent Si(O)4/2 units by CH3Si(O)3/2 units, in other words, with increasing m value in Si[OSi(O)3]3 – m [OSi(CH3) (O)2] m (O) (m=0–2). Peaks from CH3 Si(OSi)3 units in the species have also appeared as separated due to the kind of neighbor structural units. On the basis of the assignments, positions of CH3Si(O)3/2 units in the cubic octameric siloxane framework of (CH3) n Si8O 20 – n /(8 – n) – (n=2, 3), for both of which three isomers are present, have been estimated.  相似文献   

6.
Summary 1. The content of total alkaloids in the hypogeal parts ofAndrachne rotundifolia C. A. Mey. (family Euphorbicease) is 0.2–0.3% and in the epigeal parts 0.06–0.08%.The total alkaloids in both the hypogeal and the epigeal parts ofAndrachne rotundifolia consist of five or six non-phenolic bases.2. Three individual substances have been isolated: andrachnine C11H17NO2, which is a new alkaloid; base (II), giving a perchlorate with mp 139°–140° C; and base (III) with mp 135°–136° C.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 4, pp. 257–260, 1966  相似文献   

7.
Summary The roots ofFerula tschimganica Lipsky have yielded two new compounds with the compositions C18H24O4 (mp 85°C) and C17H22O3 (mp 155°C), which have been calledchimganin andchimgin. On the basis of their UV, IR, and NMR spectra and the products of alkaline hydrolysis, it has been shown that chimganin is the ester of 4-hydroxy-3-methoxybenzoic acid and chimgin that of 4-hydroxybenzoic acid with (+)-borneol.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 59–63, January–February, 1972.  相似文献   

8.
Summary From an acetonic extract of the roots ofFerula samarcandica Kor. have been isolated farnesiferol A, gummosin, and two new coumarin substances, samarcandin C24H30–32O5 and samarcandone C24H28–30O5. Samarcandin has been converted into samarcandone and their probable structures-I and II-have been established.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 2, pp. 73–77, 1968  相似文献   

9.
Summary We have isolated from the tubers ofAconitum karakolicum collected in the Kirghiz SSR, Kungei Alatau range, songorine, napelline, a base with mp 159–160°C, and the new alkaloids karakoline and a base with mp 222–224°C.The results of a study of the chemical reactions and spectral characteristics of karakoline have shown that it consists of a lycoctonine skeleton with N-ethyl and C4-methyl groups, hydroxyls at C1, C8, and C10 and a methoxy group at C15.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 199–205, March–April, 1973.  相似文献   

10.
Conclusions From the racemes ofC. xanthifolia Fresen. have been isolated a sesquiterpene lactone C16H20O4, the structural (+)-isomer of (–)-coronopilin, which has not been studied previously; structure I has been proposed for it.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 5, pp. 375–377, 1969  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