Alkaloids ofOxytropis. III. Trichophydine

A new alkaloid, which has been named trichophydine, has been isolated from the epigeal part ofOxytropis trichophysa growing in Mongolia. On the basis of the spectral characteristics of the hydrochloride, the structure of 2-O-benzoyl-2(β)-phenylethylamine, which has been synthesized previously, has been established for trichophydine.     

E.S.R. of hydrazoxyl radicals: Evidence for conformational isomers.

Thermolysis of azocarboxylates has been investigated by e.s.r. Experimental evidence for the existence of conformational isomerism in acylnitroxides has been obtained.     

Diterpenoids ofPulicaria salviifolia. III. The structure of salvicinin

The new diterpene acid salvicinin has been isolated from the epigeal part ofPulicaria salviifolia and its structure has been established as 15-acetoxy-6α-hydroxy-trans-cleroda-3,13-dien-19-oic acid. A capacity of salvicinin for undergoing lactonization in the presence of acetic anhydride has been revealed, and the lactone formed has been isolated and chracterized.     

Alkaloids ofNitraria komarovii. V. Structure and synthesis of komarovicine

The new alkaloid komarovicine has been isolated from the epigeal part of the plantNitraria komarovii Iljin et Lava. Its structure has been established on the basis of spectral and experimental results and its synthesis has been performed. A transition has been made to the alkaloids komarovine and komarovidine isolated previously.     

Rubbing-induced surface textures in nematic MBBA layers and their behaviour under applied d.c. or a.c. voltages

Surface irregularities (for example, rubbing-induced domains, and bumps) have been observed in MBBA nematic cells after special treatment of the electrodes using a conventional soap. Various techniques such as polarizing microscopy, the shadowgraph technique and computer processing of the images have been used. The behaviour of the rubbing-induced domains under a.c. or d.c. electric fields has been studied. A new flexoelectric effect has been observed leading to the dividision of the rubbing-induced domains. A simple model has been proposed (a modification of the Saupe model), which explains the structure and dividision of the rubbing-induced domains.     

Rubbing-induced surface textures in nematic MBBA layers and their behaviour under applied d.c. or a.c. voltages

Surface irregularities (for example, rubbing-induced domains, and bumps) have been observed in MBBA nematic cells after special treatment of the electrodes using a conventional soap. Various techniques such as polarizing microscopy, the shadowgraph technique and computer processing of the images have been used. The behaviour of the rubbing-induced domains under a.c. or d.c. electric fields has been studied. A new flexoelectric effect has been observed leading to the dividision of the rubbing-induced domains. A simple model has been proposed (a modification of the Saupe model), which explains the structure and dividision of the rubbing-induced domains.     

Carbohydrates of allium IX. Polysaccharides of A. suvorovii

The carbohydrate compositions of all the organs ofAllium suvorovii Rgl have been determined and it has been established that the bulk of the fructose accumulates in its bulbs. The dynamics of the accumulation of glucofructans in the bulbs has been studied and it has been found that this accumulation is a maximum in the dormancy stage.     

Alkaloids ofOxytropis. III. Trichophydine

A new alkaloid, which has been named trichophydine, has been isolated from the epigeal part ofOxytropis trichophysa growing in Mongolia. On the basis of the spectral characteristics of the hydrochloride, the structure of 2-O-benzoyl-2()-phenylethylamine, which has been synthesized previously, has been established for trichophydine.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, FAX (3712) 62 73 48. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 414–416, May–June, 1994.     

Stoffwechselprodukte von Mikroorganismen. 50. Mitteilung. Die Konfiguration der Arcanose

The L -xylo configuration of arcanose, a sugar from the antibiotic lankamycin, has been proven by its transformation into cladinose. The determination of the absolute configuration at C-3 of arcanose and cladinose has been accomplished utilizing a new procedure.     

Flavonoids ofDatisca cannibina. VI. Properties of datiscin

An authentic individual sample of datiscin has been obtained, its physicochemical constants have been determined, and additional information concerning its structure as 2′,3,5,7-tetrahydroxyflavone 3-O-[6″-(O-α-L-rhamnopyranosyl)-β-D-glucopyranoside] has been obtained.     

Polysaccharides of Polygonatum. VII. A glucofructan from P. sewerzowii

A glucofructan has been isolated from the rhizomes ofPolygonatum sewerzowii Bunge and has been called pseverin. According to its chemical and spectral characteristics, pseverin is a polysaccharide containing both inulin, 2 1, and leven, 2 6, glycosidic bonds. The problem of the correlation between the molecular structure of a glucofructan and its supermolecular organization has been considered. X-radiographic and electron-microscope studies have been made of pseverin and its acetate. It has been established that on precipitating from solution pseverin forms globular particles which aggregate to give elongated necklace-like formations. Fine lamellar structures are characteristic for the acetate.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 15–20, January–February, 1986.     

Improvements in the thin-layer chromatography of natural products. I. Thin-layer chromatography of the aflatoxins.

During the period which has elapsed since the aflatoxins were first isolated, one of the main problems has been the separation of the individual aflatoxins in pure form from aflatoxin-containing extracts. This separation has been best effected by thin-layer chromatography, and in this paper we describe how some of the difficulties may be overcome by using an appropriate combination of solvent system and silica gel preparation. For the examination of aflatoxin-containing extracts from the mycelia of Aspergillus flavus moulds, an initial freeze-drying step has been found to improve appreciably the quality of the chromatograms obtained.     

Withasteroids of Physalis. VIII. Vamonolide

A new withasteroid — vamonolide — has been isolated from the epigeal part ofPhysalis angulata L. (Solanaceae). On the basis of spectral characteristics, its structure has been established as 5α,14α-dihydroxyl-l-oxo-6α,7α-epoxy-20R,22R-with-2-enolide.     

Carbohydrates of allium IX. Polysaccharides of A. suvorovii

The carbohydrate compositions of all the organs ofAllium suvorovii Rgl have been determined and it has been established that the bulk of the fructose accumulates in its bulbs. The dynamics of the accumulation of glucofructans in the bulbs has been studied and it has been found that this accumulation is a maximum in the dormancy stage.Institute of Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedienii, No. 6, pp. 622–624, November–December, 1992.     

Porphyrins. 23. Synthesis and properties of ethanebisporphyrins

It has been shown that copper complexes of meso-hydroxy(alkoxy)methylporphyrins in trifluoroacetic acid readily dimerize to give copper complexes of ethanebisporphyrins. Selective removal of one copper atom from the dimer molecule has been achieved. The previously unknown conversion of ethanebisporphyrins to ethylenebisporphyrins has been found to take place.For Communication 22, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 24, No. 3, pp. 339–344, March, 1988.The authors wish to thank L. I. Krasovskaya for recording the mass spectra.     

Cardenolide glycosides ofCheiranthus allioni. XV. Glucocheiranthoside

Another new cardenolide glycoside has been isolated from the plantCheiranthus allioni Hort., and has been named glucocheiranthoside. Its chemical structure has been established as 3β-(4′-O-β-D-glucopyranosyl-β-D-gulmoethylpyranosyloxy)-14-hydroxy-19-oxo-5β,14β-card-20(22)-enolide. State Scientific Center for Drugs, Ukraine, 310085, Kharkov, USSR. ul. Astronomicheskaya, 33. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 269–271, March–April, 1994.     

Phytoecdysteroids ofSilene nutans. III. Nusilsterone

A new ecdysteroid — nusilsterone — has been insolated from the whole plantSilene nutans L. It has been shown that it is 1β,2β,3β,14α,20R,22R,24ζ,25-octahydroxy-5-β-cholest-7-en-6-one.     

Nonstationary processes in an ion-exchange membranes-diaphragm-ion-exchange resin system. 2. Electroosmosis

Electroosmosis through a diaphragm and/or an ion-exchange resin layer has been experimentally studied at different relative positions thereof. The velocity of electroosmosis has been calculated with allowance for averaged field strengths found for the diaphragm and ion-exchange resin from the potential drop values measured for cell sections. It has been shown that the time dependences of electroosmosis velocity are related to nonstationary polarization processes proceeding in the system.     

Diterpenoids ofPulicaria salviifolia. III. The structure of salvicinin

The new diterpene acid salvicinin has been isolated from the epigeal part ofPulicaria salviifolia and its structure has been established as 15-acetoxy-6-hydroxy-trans-cleroda-3,13-dien-19-oic acid. A capacity of salvicinin for undergoing lactonization in the presence of acetic anhydride has been revealed, and the lactone formed has been isolated and chracterized.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, Fax (3712) 62 73 48. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 246–249, March–April, 1994.     

Structure of diepoxide–diamine network polymers. II. Soluble chemical species

Gel permeation chromatography has been used to separate diepoxide–diamine oligomers, produced at a variety of stoichiometric ratios, into individual chemical species. Probability theory has been applied to calculate expressions for the amounts of each of these compounds and close agreement has been found with the experimental results. In conjunction with previous conclusions, this provides compelling evidence in favor of a purely random reaction mechanism, contrary to the inhomogeneous network-forming mechanism suggested by other workers. The effect of adding an inert diluent prior to reaction has been investigated and it is evident that the fraction of intramolecularly formed bonds increases as the concentration of polymer decreases.