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.
Summary 1. Gitogenin, diosgenin, kogagenin, ruscogenin, and tokorogenin have been isolated for the first time fromFunkia ovata Spr.2. Structures of two new steroid glycosides — funkiosides E and G — have been determined.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 69–72, January–February, 1977.  相似文献   

2.
The Raman (3200 to 10 cm–1) and far infrared (380 to 60 cm–1) spectra of gaseous fluorocyclobutane,c-C4H7F, have been recorded. A series of Q-branches observed in both of these spectra beginning at 166 cm–1 with successive transitions falling to lower frequencies have been assigned to the ring puckering vibrations of both the low energy equatorial and high energy axial conformers. These data have been fit to an asymmetric potential function of the form:V (cm–1)=(1.76±0.05)103X+(4.88±0.28)104X2+(2.12 ±0.16)103 exp(–5.66±0.41)10X2 with a reduced mass function ofg 44= 0.00386–0.00295X+0.03485X2+0.1228X3 +0.3459X4, whereX is the ring puckering coordinate. Utilizing this potential, the difference between the puckering angles for the two conformers was calculated to be 4° with the equatorial conformer having the larger value of 28°. This potential function is consistent with an energy difference between the equatorial and axial forms of 447 cm–1 (1.28 kcal/mol) and a barrier to ring inversion from the equatorial to the axial conformation of 713 cm–1 (2.04 kcal/mol). Experimental values for the enthalpy difference between the two conformers have been determined for both the liquid (400±30 c–1) and gas (413±43 cm–1) from investigations of the Raman spectra at variable temperatures. The conformational stability, enthalpy difference, structural parameters, and fundamental vibrational frequencies, which have been determined experimentally, are compared to those obtained from ab initio Hartree-Fock calculations employing the 3-21G, 6-31 G*, and 6-31 G** basis sets.For part LVIII, seeStruct. Chem. 1991,2, 195.Taken in part from the thesis of M. J. Lee, which has been submitted to the Department of Chemistry in partial fulfillment of the Ph.D. degree, May 1991.  相似文献   

3.
Water-soluble polysaccharides have been isolated from two species ofEremurus — E. lactiflorus andE. luteus — with yields of 13.5% and 20.5%, respectively. They contained mainly glucose and mannose in ratios of 1:5 and 1:3.1. The polysaccharides ofE. lactiflorus were separated from a column of DEAE-cellulose. The yield of neutral fraction was 10.3%. Gel filtration of the polysaccharides on Sephadex G-200 showed their polydispersity. Homogeneous fractions were obtained by fractional precipitation with ethanol. They have been characterized with respect to monosaccharide composition, molecular weight, and IR spectra.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 604–608, September–October, 1979.  相似文献   

4.
In addition to the alkaloids known previously from this plant, haplofoline and folifine, from the epigeal part ofHaplophyllum foliosum we have isolated norgraveoline with mp 288–289°C (decomp. from acetone), and myrtopsine with mp 201–202°C (from chloroform), []D-5° (c 0.05; methanol), which were first obtained fromHaplophyllum dubium andMyrtopsis sellingii, respectively. We have confirmed by the PMR-spectroscopic method the positions of the substituents in the dihydrofuran ring of myrtopsine suggested previously on the basis of biogenetic considerations. In addition, it has been established that the substituents are present in the trans form. This is the first time that myrtopsine has been detected in plants of the genusHaplophyllum.Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 613–616, September–October, 1981.  相似文献   

5.
Summary The structures of aloperine and allylaloperine (fromSophora alopecuroides L.) — alkaloids of a new structural type for the genusSophora — have been established by chemical and spectral methods. A number of parameters, NMR spectra, and mass spectra characterizing this class of compounds has been obtained. The partial synthesis of allylaloperine has been performed.All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 30–37, January–February, 1975.  相似文献   

6.
Summary Two new steroid glycosides of the furostanol series have been isolated fromAllium narcissiflorum Wills., and their structures have been shown.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 184–188, March–April, 1976.  相似文献   

7.
Two steroid glycosides belonging to the furostan series — funkioside B and protodioscin — have been isolated from the seeds of the plantMelilotus tauricus (Bieb.).Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 766–770, November–December, 1994.  相似文献   

8.
Ten individual compounds have been isolated from the epigeal part ofAlhagi sparsifolia Shap. in various stages of vegetative growth. Their structures have been established by a study of PMR spectra, physicochemical properties, and the products of chemical transformations: (–)-epicatechin, (–)-epigallocatechin, (–)-epigallocatechin gallate, (+)-catechin, (+)-gallocatechin, proanthocyanidin B-2, (–)-epigallocatechin-(4–8)-(–)-epicatechin, epigallocatechin gallate-(4–8)-(–)-epicatechin, proanthocyanidin B-1, and (–)-epicatechin-(4–8)-gallocatechin.The materials of this paper were presented at the Second International Symposium on the Chemistry of Natural Compounds (SCNC, Eskiehir, Turkey, October 22–24, 1996).Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 232–237, March–April, 1997.  相似文献   

9.
Three new alkaloids have been isolated from the epigeal part ofNitraria komarovii — peganine N-oxide, N-allylschoberine, and dehydronitramidine. Their structures have been determined on the basis of chemical transformations and spectral results.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 780–783, November–December, 1994.  相似文献   

10.
The structures of two new steroid glycosides of the spirostan series isolated from inflorescences of the plantAllium karataviense Rgl. (family Alliaceae) — karataviosides E and F — have been shown on the basis of chemical transformations and spectral characteristics.Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 69–73, January–February, 1984.  相似文献   

11.
Two steroid glycosides belonging to the spirostan series — trillin and dioscin — have been isolated from the seeds of the plantMelilotus tauricus (Bieb.) Ser.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 770–772, November–December, 1994.  相似文献   

12.
The infrared (3200 to 400 cm–1) spectra of gaseous and solid and Raman (3200 to 20 cm–1) spectra of liquid and solid ethyl chlorosilane-Si-d2, CH3CH2SiD2Cl, have been recorded. Both the gauche and trans conformers have been identified in the fluid phases, but only the gauche conformer remains in the solid phase. Variable temperature (–105 to –150°C) studies of the infrared spectra of CH3CH2SiH2Cl dissolved in liquid krypton have been carried out. From these data, the enthalpy difference has been determined to be 78±11 cm–1 (0.93±0.13 kJ/mol), with the gauche conformer the more stable form. Utilizing the frequencies of the silicon-hydrogen stretches, from the chlorosilane-Si-d isotopomer, Si—H bond distances of 1.481 and 1.480 Å have been obtained for the gauche conformer and 1.481 Å for the trans conformer. Complete vibrational assignments are proposed for both isotopomers which are consistent with the predicted frequencies utilizing the force constants from ab initio MP2/6-31G(d) calculations. Both the infrared intensities and the Raman activities and depolarization values have been obtained from the ab initio calculations. Complete equilibrium geometries have been determined by ab initio calculations employing the 6-31(d), 6-311++G(d,p), and 6-311+G(2d,2p) basis sets with full electron correlation by the Moller–Plesset (MP) perturbation method to second order. Continuing the previously reported rotational constants from five different isotopomers and the ab initio predicted structural parameters, adjusted r 0 parameters have been calculated, which are compared to the corresponding r s parameters. The results are discussed and the theoretical values are compared to the experimental values when appropriate.Taken in part from the dissertation of Y. E. Nashed, which will be submitted to the Department of Chemistry in partial fulfillment of the Ph.D. degree  相似文献   

13.
Two new diterpenoids of the clerodane series — salvin and salvinin — have been isolated from the epigeal part ofPulicaria salviifolia Bgl. in Mem. A structure and a most probable stereochemistry are proposed.Presented at the VIIth Indo-Soviet Symposium on the Chemistry of Natural Compounds [16].Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 201–205, March–April, 1985.  相似文献   

14.
Water-soluble polysaccharides, pectin substances, and hemicelluloses have been isolated fromMorus leaves, and their qualitative and quantitative compositions have been determined. The polysaccharides obtained by extraction with hot water have been investigated for hypoglycemic activity. A polysaccharide fromMorus alba proved to have the highest sugar-lowering activity.Materials presented at the IInd International Symposium of the Chemistry of Natural Compounds.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 789–791, November–December, 1997.  相似文献   

15.
Two alkaloids of a new type — komarovine and komarovidine — have been isolated from the epigeal part of theNitraria komarovii. Their structures — 3-(quinolin-8'-yl)--carboline and 3-(quinolin-8'-yl)-5,6-dihydro--carboline, respectively — have been established by synthesis.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 192–195, March–April, 1981.  相似文献   

16.
Polysaccharides have been isolated from the epigeal and hypogeal organs ofAcanthophyllum pungens and their qualitative presence and quantitative compositions have been determined. A neutral polysaccharide from the epigeal organs is of the galactan type, while a neutral polysaccharide from the roots is a glucogalactan.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 40 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 693–695, September–October, 1997.  相似文献   

17.
Absttract Berberine, isocorydine, glaucine, thalicmidine, aromoline, oxyacanthine, and the new 1-benzylisoquinoline alkaloid turcomanine have been isolated fromBerberis turcomanica Kar. The structure of the new alkaloid has been established on the basis of chemical transformations and spectral characteristics. This is the first time that isocorydine, thalicmidine, aromoline, and oxyacanthine have been isolated from this plant.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 74–76, January–February, 1996. Original article submitted May 22, 1995.  相似文献   

18.
Summary The leaves ofAjuga turkestanica (Rg1.) Briq. have yielded a new ecdysone — 22-acetyl-cyasterone. The mass spectrum of this new ecdysone and the features of it due to the presence of the acetoxy group at C-22 have been discussed.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 215–219, March–April, 1978.  相似文献   

19.
The values of the second dissociation constant, pK2, and related thermodynamic quantities of 4-(N-morpholino)butanesulfonic acid (MOBS) and N-tris(hydroxymethyl)-4-aminobutanesulfonic acid (TABS) have already been reported over the temperature range 5–55°C including 37{°}C. This paper reports the pH values of twelve equimolal buffer solutions at designated pH (s) with the following compositions: (a) mixtures of MOBS (0.05 mol-kg–1) + NaMOBS (0.05 mol-kg–1); (b) MOBS (0.08 mol-kg–1) + NaMOBS (0.08 mol-kg–1); (c) MOBS (0.08 mol-kg–1) + NaMOBS (0.08 mol-kg–1) + NaCl (0.08 mol-kg–1); (d) TABS (0.05 mol-kg–1) + NaTABS (0.05 mol-kg–1); and (e) TABS (0.08 mol-kg–1) + NaTABS (0.08 mol-kg–1); and (f) TABS (0.08 mol-kg–1) + NaTABS (0.08 mol-kg–1) + NaCl (0.08 mol-kg–1). Two buffer solutions have ionic strengths I= 0.05 mol-kg–1, another two have I=0.08 mol-kg–1, and the remaining two buffer solutions have I= 0.16 mol-kg–1, which is close to that of the clinical fluids (blood serum). These buffers have been recommended as a useful pH standard for the measurements of physiological solutions. Conventional pH values of all six buffer solutions from 5–55°C, as well as those obtained from the liquid junction potential correction at 25 and 37{°}C have been calculated. The flowing-junction calomel cell has been utilized to measure Ej, the liquid junction potential.  相似文献   

20.
Summary 1. The new sesquiterpene lactone tanachin (I) has been isolated from a chloroform extract ofTanacetum pseudoachillea C. Winkl.2. With the aid of double and triple resonances, the chemical shifts and coupling constants of the protons of (I) have been determined. On the basis of these results and by the application of a paramagnetic shift reagent —Eu (FOD)3 — the structure of 1,6-dihydroxygermacr-4,10(14),11(13)-trien-8,12-olide has been established for tanachin. The orientations of the hydroxy groups have been determined.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 462–467, July–August, 1976.  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