Applications of1H and13C NMR spectroscopy in structural investigations of Vinca indole alkaloids

This review considers the laws connecting the parameters of the¹H and¹³C NMR spectra with the structure of the substances and the use of these laws for solving structural and stereochemical problems of theVinca indole alkaloids and other compounds of closely related structure. For each type of alkaloids, characteristic features of the PMR and¹³C NMR spectra are given that permit the structures of similar bases to be established and their stereochemical identification to be performed.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 3–15, January–February, 1986.     

13C-NMR studies on the cevanine alkaloids : the application of 13C-NMR spectrum for structure elucidation of new alkaloids,baimonidine and isoverticine

The ¹³C-NMR spectra of seven cavanine alkaloids isolated from Veratrum and Fritillaria plants were measured and their signals were assigned, and these results were applicated for structure elucidation of two new cevanine alkaloids, baimonidine and isoverticine, isolated from mature Fritillaria verticillata.     

Alkaloids of Papaver fugax

Papaver fugax growing on the shore of Lake Kazenoi Am in the Checheno-Ingushskii ASSR at the boundary with the Dagestan ASSR has yielded 0.39% of alkaloids. Seven alkaloids have been isolated, of which cheilanthifoline, scoulerine, and reticuline have been detected in this species for the first time, while it is the first time that d-remeroline has been found in a plant of thePapaver genus.Pyatigorsk Pharmaceutical Institute. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 559–562, July–August, 1988.     

An investigation of the alkaloids of Ammothamnus lehmanni the structure of lehmannine

Summary 1. The qualitative and quantitative composition of the combined alkaloids from the leaves, stems, seeds, and roots ofAmmothamnus lehmanni Bge. according to its vegetation periods have been studied.2. It has been found that the young plant contains predominantly the N-oxide forms of the matrine alkaloids, and as the plant develops these are reduced to the free bases.3. A new base lehmannine, C₁₅H₂₂ON₂ has been isolated for which 12,13-dehydromatrine is proposed as the most probable structure.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 377–380, May–June, 1975.     

The biosynthesis of the alkaloids of Goebelia pachycarpa

Summary 1. Qualitative and quantitative compositions of the main alkaloids in five development phases of theGoebelia pachycarpa C. A. Mey. have been determined.2. The radioactivities of the alkaloids isolated after feeding the plant with assumed precursors -[2-¹⁴C] lysine and [1,5-¹⁴C] cadaverine — show that vigorous synthesis of alkaloids takes place in the flowering and budding periods.3. The results of an investigation of the oxidation products and of the alkaloids introduced and isolated after the feeding of plants with labelled matrine and labelled sophocarpine show that the alkaloids undergo interconversion without intramolecular changes.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh, Soedinenii, No. 4, pp. 549–552, July–August, 1977.     

Synthesis of trans -N-2-aryl(heteryl)ethenamidines

2-Amino-2-arylethylamides1 carrying electron-donating substituents in thepara position are transformed by hot POC1₃ to the the title compounds2, presumably via iminochlorides 7 and imidazolium derivatives8. Amides lacking this para-substituent give rise to chloroamidines11 under these conditions.m-Methoxyphenethylamide1t and POCl₃ form, besides11f, an isoquinoline derivative3. The involvement of an imidazolium compound8 in the formation of ethenamidines has been verified by the synthesis of2a from10. Reaction of amide1w with PCl₅ in the cold leads to, besides the chloroamidine11c, thecis-ethenamidine12 which equilibrates with thetrans-isomer2o in hot toluene. Thienylethyl urea13 converted by hot POCl₃ to the imidazoline16, while phenylpropylamide17 forms only the iminochloride18a. Contribution No. 752 from Research Centre     

Extraction of the total alkaloids from the epigeal part of Aconitum orientale

The process of extracting the total alkaloids fromAconitum orientale with aqueous solutions of a number of electrolytes has been investigated. It has been established that it is most desirable to use 2% solutions of H₂SO₄ and 5% solutions of CH₃COOH. The optimum parameters of the process have been found, under which the degree of extraction of the total alkaloids averages 96%.I. G. Kutateladze Institute of Pharmacochemistry, Georgian Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 816–821, November–December, 1991.     

Extraction of the total alkaloids from the epigeal part of Aconitum orientale

The process of extracting the total alkaloids fromAconitum orientale with aqueous solutions of a number of electrolytes has been investigated. It has been established that it is most desirable to use 2% solutions of H₂SO₄ and 5% solutions of CH₃COOH. The optimum parameters of the process have been found, under which the degree of extraction of the total alkaloids averages 96%. I. G. Kutateladze Institute of Pharmacochemistry, Georgian Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 816–821, November–December, 1991.     

The structure of vinerine and vineridine

Summary 1. The epigeal part ofV. erecta gathered in the Tashkent Oblast in the early vegetation period contains a mixture of alkaloids (2.7%). Separation of the total alkaloids gave vincanine, vincanidine, vinervine, akuammine, kopsinine, pseudokopsinine, and the new bases vinerine and vineridine.2. The structure of vinerine has been established by a study of the IR, NMR, and mass spectra. Vineridine is isomeric with vinerine at C₃ and C₇.3. A new base, hydroxyindole reserpinine, has been obtained from reserpinine.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 4, pp. 260–265, 1966     

A study of the alkaloids of plants of the genusStephania

Summary Four alkaloids have been isolated from the tubers ofStephania glabra (Roxb.) Miers. (synonymSt. rotunda Lour.) collected in the Democratic Republic of Vietnam:l-tetrahydropalmatine and three previously undescribed bases (A -C₁₉H₁₈O₂N, C - C₂₀H₂₅O₄N, and D -C₂₁H₂₅O₄N).Khimiya Prirodnykh Soedinenii, Vol. 1, No. 6, pp. 392–394, 1965.The substances in this paper are denoted by letters. The novelty of these substances has not been established, which contradicts the rules of this journal. The paper is printed as an exception (Editiorial Board).     

Investigation of Aconite alkaloids

Summary The composition of the alkaloids in plants of the genus Aconitum —A. kirinense,A. altaicum, A. coreanum, andA. nemorosum — has been studied. Four new alkaloids of composition C₂₆H₄₁O₈N·HNO₃, C₃₅H₄₁O₁₀N·HBr, C₂₀H₂₅O₃N, and C₂₃H₂₉O₆N have been isolated.Khimiya Prirodnykh Soedinenii, Vol. 1, No. 2, pp. 113–116, 1965.     

Alkaloids of the epigeal part of Aconitum talassicum. Structure of actaline

The epigeal part ofAconitum talassicum M. Pop. has yielded, in addition to five alkaloids known previously, kobusine, pseudokobusine, and the new alkaloid actaline. The structure of the latter has been established on the basis of an x-ray structural analysis. Actaline is the first C₂₀ diterpene alkaloid with a lycoctonine skeleton.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, Vol. 1, pp. 39–44, January–February, 1989.     

Alkaloids ofAndrachne rotundifolia

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     

Binary Mixtures of Liquid Crystalline Ester Bismaleimides

Abstract

A binary system consisting of a chlorohydroquinone-based ester bismaleimide (3-Cl), T _m = 238°C, and a methylhydroquinone-based ester bismaleimide (3-Me), T _m = 251°C, was investigated for the purpose of improving processability by widening the nematic phase range before polymerization. Calculations based on the Schroeder-van Laar equation predicted a system eutectic composition of 41% 3-Me monomer and a eutectic temperature of 202°C. Experiments found the eutectic composition at 35% 3-Me and the eutectic temperature at 218.5°C. Discrepancies between experimental results and theoretical predictions are likely due to error in measured heats of fusion either due to impurities in the samples or due to the reactive nature of the components being considered. Thermal cycling was also found to have a significant melting point depression effect. While significant depression of the system melting point was achieved, polymerization still occurred immediately after melting in all systems evaluated. All mixtures could be polymerized from the nematic phase to yield a solid which retained the nematic orientation of the starting polymer melt.     

Reverse Phase Isolation of Pyrrolizidine Alkaloids

Abstract

A new liquid chromatography method for the isolation of pyrrolizidine alkaloids has been developed. The use of reverse phase high pressure liquid chromatography with a methanol - .01 M KH₂ PO₄ (pH 6.3) solvent system is discussed. Pyrrolizidine alkaloids from Senecio vulgaris, S. longilobus, and S. jacobaea have been isolated and identified.     

2,10-Didemethylcolchicine — A new alkaloid from Merendera robusta

The alkaloid complex ofMerendera robusta Bge. (familyLiliaceae) growing in the Tashkent province of the Uzbek SSR has been investigated. The main alkaloids of this plant are colchicine and colchamine. Eleven tropolone alkaloids and their photochemical isomers have been isolated and identified. A new alkaloid of phenolic nature has been isolated for which the structure of 2,10-didemethylcolchicine has been established.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 67–71, January–February, 1991.     

Structure of the new monoterpenoid liganolide

The structure of the new ester liganolide C₂₇H₃₈O₈, isolated from the roots ofLigularia thomsonii has been established by x-ray structural analysis. Liganolide is a monoterpenoid including a six-membered ring with substitutents at C(2), C(3), and C(4), and an epoxy group at C(1) and C(6).Deceased.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Science, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 799–803, November–December, 1987.     

Alkaloids ofNuphar luteum

Summary 1. The dry rhizomes ofNuphar luteum L. have yielded three sulfur-containing alkaloids: two — thiobinupharidine and neothiobinupharidine — were known substances, the third with composition C₃₀H₄₂O₄N₂S being new and having been given the name of nuphleine.2. A possible structure has been proposed for nuphleine.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 2, pp. 178–182, 1967