Polysaccharides of Saponin-Bearing Plants. XV. Structure of Glucoarabinogalactan from Acantophyllum Borszczowii Roots

The structure of the branched polysaccharide glucoarabinogalactan was investigated by periodate oxidation, methylation, and ¹³C NMR spectroscopy. The main chain consists of -16-bonded galactopyranoses. 12-Bonded D-glucopyranoses and 13-bonded D-galactopyranoses are located on the unreducing ends. There is a short side chain with -13-bonded L-arabinopyranoses.     

MO LCAO calculations and the electronic spectra of the anions of cyclopent-4-ene-1,3-diones and indane-1,3-diones

The Hückel approximation in MO LCAO is used to show that the anion system of cyclopent-4-ene-1,3-dione should have two ^* transitions: a weak one at long wavelengths, NV₁, and a strong one at short wavelengths, C=C(1,3)V₁. An ethylene, phenyl, or acyl group at position 2 gives rise to a new strong band, NC=C(2), Nbenz, or NC=O (2). A p-nitrophenyl group at position 2 gives rise to a strong NNO₂ band, which overlaps the weak NV₁ band, while the Nbenz band becomes weak and is virtually lost from the spectrum.     

Copper(II)-disulphide interaction: a spectroscopic and electrochemical study of the interaction of copper(II) with an imidazole-containing disulphide

Summary The interaction of copper(II) salts with the imidazole-containing disulphide 5-(1,2,5-dithiazaepan-5-ylmethylene)-4-methyl-2-ethyl imidazole (MAMI) in MeOH have been investigated. The 11 Cu(ClO₄)₂MAMI system exhibited a single ligand field band at ca. 12200cm^-1, an intense shoulder at ca. 31500 cm^-1 and a less intense split feature at 24400 and 25300cm^-1 assignable to S() Cu^II and S() Cu^II charge transfer (CT) transitions, respectively. The e.p.r. parameters suggested the presence of a CuN₂SO chromophore, however; the 11 Cu(NO₃)₂MAMI system did not exhibit a S Cu^II CT band and the g value was comparatively high. An electrochemical study of the 11 Cu(ClO₄)₂MAMI system in MeOH revealed that the copper-disulphide interaction, though weaker, would confer a high redox potential as well as reversibility, similar to the copper-thioether interaction.     

Cyclic voltammetric and e.s.r. studies of a tetraaza 14-membered macrocyclic copper(II) complex derived from 3-salicylideneacetylacetone ando-phenylenediamine: stabilization and activation of unusual oxidation states

Summary A 14-membered macrocyclic Schiff base derived from 3-salicylideneacetylacetone ando-phenylenediamine acts as a tetradentate and strongly conjugated ligand to form a cationic solid complex with CuCl₂. U.v.-vis. and e.s.r. spectral data reveal a strong ligand to metal -interaction in the square planar complex. C.v. data reveal that the title ligand is able to stabilize the copper(III) oxidation state more effectively than comparable saturated or partially unsaturated macrocyclic ligands and confers a weaker tendency for reduction of copper(II) to copper(I) and copper(0). While the inclusion of a PPh₃ ligand suppresses the Cu⁰ Cu^I Cu^II oxidation, imidazole and pyridine strongly enhance the Cu^II Cu^III oxidation of the complex.     

Excited Π states of divinyl chalcogenides and chalcophenes

Electron transitions in divinyl chalcogenides (CH₂=CHXCH=CH₂, where X is S, Se, or Te) have been analyzed using UV absorption spectra of dialkyl and alkyl vinyl chalcogenides. The following relations for the orbital energies are found: ^* < ^* < ^* < ^* for Te and ^* < ^* < ^* < ^* for S and Se. For chalcophenes, a correlation between the energy of the excited state (E ^*) of specific symmetry, the ionization potential (I) and the electron affinity (EA) is obtained:E ^*=const+(I+EA)/2. The electron affinity of divinyl chalcogenides is estimated. The correlation between the excited ^* states of divinyl chalcogenides and chalcophenes is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 831–835, May, 1994.     

The electronic spectrum of acrylonitrile

The vapor absorption spectrum of acrylonitrile CH₂CHCN has been measured in the vacuum ultraviolet region. In addition, an all-valence-electron molecular orbital calculation has been used to calculate the electronic structure and spectrum of the molecule. On the basis of the MO calculation, as well as a vibrational analysis of the observed spectrum, several electronic transitions are assigned. The lowest energy absorption band (2107Å, = 150) is assigned as an n ^* transition. Absorption bands at 2030Å (=1600), 1725Å ( = 2100), and 1570Å ( = 1920) are assigned as 0–0 bands associated with transitions that are, respectively, ^*,^*, and ^* in character.

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Zusammenfassung Das UV-Absorptionsspektrum von dampfförmigen Acrylnitril wurde gemessen und eine CNDO/2-Rechnung für die Elektronenstruktur durchgeführt. Auf dieser Basis konnten unter Zuhilfenahme der Analyse der Schwingungsstruktur im beobachteten Spektrum mehrere Banden zugeordnet werden: die 2107-Å-Bande ( = 150) einem n^*-Übergang, die drei Banden bei 2030Å ( = 1600), 1725Å ( = 2100) und 1570 Å ( = 1920)0-0-Übergängen von ^*-, ^*- bzw. ^*-Banden.

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Résumé Mesure du spectre d'absorption en phase vapeur de l'acrilonitrile CH₂CHCN dans la région de l'ultraviolet. Par ailleurs, la structure électronique et le spectre de la molécule ont été calculés à l'aide d'une méthode des orbitales moléculaires semi-empirique pour tous les électrons de valence. Sur cette base, ainsi que sur une analyse vibrationnelle du spectre expérimental, on procède à l'attribution de plusieurs transitions électroniques. La bande d'absorption de plus basse énergie (2107 Å, = 150) est attribuée à une transition n ^*. Les bandes d'absorption à 2030Å ( = 1600), 1275Å ( = 2100) et 1570Å ( = 1920) sont considérées comme des bandes 0 - 0 associées à des transitions ^*, ^* et ^* respectivement.

     

Triterpene Glycosides of Tetrapanax papyriferum. II. Isolation and Structure Determination of Glycosides St-E2, St-F2, St-J2, and St-K2 from Stem Bark

Stem bark ofTetrapanaxpapyriferum yielded the new triterpene glycosides 3-O-[-D-glucopyranosyl-(13)]--D-galactopyranosyl-(12)-O--L-arabinopyranosides of oleanolic and echinocystic acids and their 28-O--L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl esters. Their structures were established using chemical and physicochemical methods     

Triterpene glycosides of alfalfa. VI. Medicoside L

A new triterpene pentaglycoside — medicoside L — has been isolated from the roots ofMedicago sativa L. (Leguminosae). It has the structure of medicagenic acid 28-O--D-glucopyranoside 3-O-{[O--D-glucopyranosyl-(1 2)][O--L-rhamnopyranosyl-(1 3)]-O--D-glucopyranosyl-(1 2)}--D-glucopyranoside.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 221–228, March–April, 1990.     

Triterpene glycosides of Hedera taurica

From the leaves of Crimean ivy we have isolated the previously known glycosides 3-O--L-Ara_p-28-O-[O--L-Rha_p-(14)-O--D-Glc_p-(16)--D-Glc_p]hederagenin, 3-O-[O--L-Rha_p-(12)--L-Ara_p]-28-O-[O--L-Rha_p-(14)-O--D-Glc_p-(16)--D-Glc_p]oleanic acid and -hederagenin, and 3-O-[O--L-Rha_p-(12)--L-Ara_p]-28-O-[O--D-Glc_p-(16)--D-Glc_p]hederagenin and a new one: tauroside H₁ — 3-O-[O--L-Rha_p-(12)-O--L-Ara_p]-28-O-[O--L-Rha_p-(14)-O--D-Glc_p-(16)--D-Glc_p]echinocystic acid.M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 522–528, September–October, 1992.     

Kinetics and mechanism of the decomposition of CS2, OCS,and SCl2 in a radiofrequency pulse discharge

The identification of transient species in r.f. discharges and measurement of rate coefficients for their reactions contributes to the understanding of the complex mechanisms in r.f. plasma chemistry. Using kinetic spectroscopy in conjunction with a short-duration r.f. pulse to investigate the decomposition of CS₂, OCS, and SCl₂ at low pressure, it has been shown that the predominant primary dissociation steps are CS₂CS+S, OCSCO+S(¹D), and SCl₂S+Cl+Cl. With OCS the most important subsequent steps involved the formation and removal of S₂: S(¹D)+OCSCO+S₂(a¹), S₂(a¹)+MS₂(X³)+M, (13), and 2S₂+MS₄+M(15). Taking the previously published value of k₁₂, computer simulation gave the rate coefficient values k₁₃=6.4±2.4×10⁸ mol^–1 dm³ s^–1 and k₁₅=1.8±0.5×10¹³ mol^–2 dm⁶ s^–1 at 295±3 K.     

Triterpene glycosides of Pulsatilla dahurica structures of glycosides A,B, C,and D

The isolation of four triterpene glycosides from the roots of the dahurian anemonePulsatilla dahurica (Fisch. ex DC) Spreng, is described together with their identification, on the basis of chemical transformations, spectral characteristics, and literature analogies, as hederagenin 3-O--L-arabinoside, hederagenin 3-O-[O--D-glucopyranosyl-(12)--L-arabinopyranoside], hederagenin 3-O--L-arabinopyranoside 28-O-[O--L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranoside], and hederagenin 3-O-[O--D-glucopyranosyl-(14)--L-arabinopyranoside] 28-O-[O--L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranoside].Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 349–356, May–August, 1992.     

Triterpene glycosides of the holothurian Eupentacta pseudoquinquisemita

The holothurianEupentacta pseudoquinquisemita Deichmann collected in Kraternaya Bay, Ushishir Islands has yielded two triterpene pentaosides — the previously known cucumarioside C₂, and cucumarioside H, which is a new glycoside. With the aid of¹³C NMR spectroscopy and solvolytic desulfation its structure has been determined as 6-acetoxy-3-([3-O-methyl--D-xylopyranosyl-(1 3)--D-glucopyranosyl-(1 4)] [-D-xylopyranosyl-(1 4)] [-D-xylopyranosyl-(1 2)]--D-quinovopy-ranosyl-(1 2)-(4-O-sulfato--D-xylopyranosyloxy)holosta-7,22,24(trans)-triene. Cucumarioside H was also identified inEupentacta (=Cucumaria)fraudatrix from Posyet Bay, Sea of Japan.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 221–225, March–April, 1988.     

The UV spectra of arsines and arsine selenides

Short-wavelength n_Se ^* and long-wavelength n_Se ^* bands are observed in the UV spectra of saturated trialkylarsine selenides in the near-UV region. The n_x ^* band in going from arsine selenides to arsine sulfide and then to arsine oxides is shifted hypsochromically, as in the corresponding phosphorus compounds. The n_x ^* band is only slightly sensitive to the chalcogen. Saturated trialkylarsines, in contrast to alkylphosphines, absorb in the near UV region (the n_As ^* band is at 208 nm).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 940–942, April, 1990.     

Synthesis of 3, 6-anhydrocellulose by the saponification of 6-O-tosyl-2, 3-di-O-acetylcellulose

Summary 1. Derivatives of cellulose containing 3, 6-anhydro rings have been synthesized by the following route: cellulose 6-O-tritylcellulose 6-O-trityl-2, 3-di-O-acetylcellulose 2, 3-di-O-acetylcellulose 6-O-tosyl-2, 3-di-O-acetylcellulose 3, 6-anhydrocellulose.2. The composition of the 3, 6-anhydrocellulose has been studied by exhaustive acetylation, nitration, and periodate oxidation, and also by IR spectroscopy.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 6, pp. 372–375, 1966     

Triterpene glycosides ofHedera helix II. Determination of the structure of glycoside L-6d from common ivy leaves

A new hederagenin pentaoside — glycoside L-6d — has been isolated from the leaves of common ivyHedera helix L., fam. Araliaceae, and its structure has been determined by using various NMR-spectroscopic methods. Glycoside L-6d is hederagenin 3-O-[O--L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl-(14)-O--L-rhamnopyranosyl-(12)--L-arabinopyranoside.Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 746–752, November–December, 1994.     

PMR spectra of 2-substituted pyrazines and the corresponding pyrazine N-oxides and N,N′-dioxides

The PMR spectra of pyrazine, its 2-substituted derivatives, and the corresponding N-oxides and N,N-dioxides were investigated. The character of the change in the chemical shifts in the N-oxides and N,N-dioxides of unsubstituted pyrazine indicates the electron-donor effect of the NO group. An additive effect of the NO groups on the chemical shifts of the ring protons is observed in pyrazine N,N-dioxide. An appreciable interaction of the substituent with the N₍₁₎O group and a weak interaction with the N₍₄₎O group occur in N-oxides and N,N-dioxides of 2-substituted pyrazines. A significant increase in the ortho and meta spin-spin coupling constants of the ring protons is noted when the nitrogen atoms are oxidized. The sign of the spin-spin coupling constant (J₃₅) through the NO group was determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 266–273, February, 1972.     

Proanthocyanidins of Polygonum coriarium. I

Six proanthocyanidins have been isolated from the roots ofPolygonium coriarium. The structures of three oligomeric proanthocyanidins have been established: taranin, consisting of [epigallocatechin gallate]-(48)-[epigallocatechin gallate]-(48)-[epigallocatechin-(48)-epigallocatechin₂-(48)-epigallocatechin; taranoside A - [epigallocatechin gallate]-7-0-[-(16)--D-Glcp]₃-(48)-[epigallocatechin-(48)-epigallocatechin]₂-(48)-gallocatechin; and taranoside B - [epigallocatechin gallate]-7-O-[-(16)--D-Glcp]₄-(48)-[epigallocatechin-(48)-epigallocatechin]₂-(48)-epigallocatechin-(48)-[epigallocatechin gallate).Institute of the Chemistry of Plant Substances, Uzbekistan Republic Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 59–67, January–February, 1992     

Triterpene glycosides ofSophora japonica seeds

We have isolated from the seeds of Sophora japonica the known soyasaponogenol B-3-[O--D-glucopyranosyl-(12)-O--D-glucopyranuronoside] (adzukisaponin II), soyasapogenol B [3-O--galactopyranosyl-(12)-O--L-glucopyranuronoside] (soyasaponin III), soyasapogenol B 3-(O--L-rhamnopyranosyl-(12)-O--L-glucopyranosyl-(12)-O--D-glucopyranuronoside] (adzukisaponin V), soyasapogenol B 3-(O--D-rhamnopyranosyl-(12)-O--D-galactopyranosyl-(12)-O--D-glucopyranuronoside] (soyasaponin I), and the new glycoside (1) — soyasapogenol B 3-[O--D-glucopyranuronoside]. The structure of this glycoside has been established on the basis of the results of enzymatic, complete, and partial hydrolyses and¹³C NMR spectra.Simferopol' State University and Kursk State Medical Institute, Kursk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 709–713, September–October, 1995. Original submitted March 3, 1995.     

Secondary metabolites of Astragalus danicus Retz. and A. inopinatus Boriss.

The chemical composition of the above-ground parts of Astragalus danicus and A. inopinatus collected in the Baikal region (Eastern Siberia) was studied for the first time. From A. danicus, pentacyclic triterpene saponins were isolated and identified, viz., 3-O-(-glucuronopyranosyl)-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-d-xylopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-d-glucopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-l-rhamnopyranosyl)-(12)-O-(-d-xylopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-l-rhamnopyranosyl)-(12)-O-(-d-glucopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-methyl-d-chiro-inositol, and linolenic acid. In A. inopinatus, the same saponins were identified as well as tricosan-1-ol and tetracosan-1-ol, 5,7,4"-trihydroxyflavon (apigenin), and a tetracyclic triterpenoid, 20(R),24(S)-epoxycyclolanost-9(11)-ene-3,6,16,25-tetrol (cycloastragenol). All reported compounds from the both genus of Astragalus were isolated for the first time. Methanolic extracts of A. danicusand A. inopinatus exhibited low inhibitory activity with respect to the growth of HeLa cells. The chloroform fraction of A. danicus showed a strong antimicrobial activity against Staphylococcus aureus and a strong cytotoxic activity against HeLa cells.