Polysaccharides ofUngernia. VII. Partial hydrolysis of the mannan of the bulbs ofU. vvedenskyi

4-O--D-Manopyranosyl-D-mannose, O--D-mannopyranosyl-(l4)-O--D-mannopyranosyl-(14)-D-mannose, and 0--D-mannopyranosyl-(14)-O--D-mannopyranosyl-(l4)-O--D-mannopyranosyl-(l4)-D-mannose have been isolated fron the products of the partial hydrolysis of ungeromannan-V, obtained fron the bulbs ofUngernia vvedneskyi, and have been identified. This set of oligosaccharides confirms the regular structure of the carbohydrate chain of ungeromannan-V, which consists of a linear sequence of -14-bound D-mannose residues.DeceasedTranslated from Khimiya Prirodnykh Soedineii, No. 4, pp. 434–436, July–August, 1981.     

The phenomenon of conglomerate crystallization. XX. Spontaneous resolution in coordination compounds. XVIII.

The title compound, [cis-Co(en)₂(NO₂)₂](NO₂) (1), crystallizes in the polar, nonenantiomorphic, monoclinic space group, Cc, with lattice constants:a=9.198(2) Å,b=12.444(2),c=9.963(3), and=96.76(2)°;V=1132.39 ų andd(calc;Z=4) =1.860 g cm^–3. Thus, with NO_2– as the counteranion, [cis-Co(en)₂(NO₂)₂] crystallizes in a heterochiral lattice containing racemic pairs of cations. A total of 2699 data were collected over the range of 4°270°; of these, 1859 (independent and withI3(I)) were used in the structural analysis. Data were corrected for absorption (=15.465 cm^–1) and the relative transmission coefficients ranged from 0.9934 to 0.7112. Refinement was carried out for both lattice polarities and the finalR(F) andR _w (F) residuals were, respectively, 0.0242 and 0.0202 for (–––) and 0.0264 and 0.0243 for (+++). Thus, the former was selected as correct for our specimen.Unlike all previous X-ray diffraction studies of the structural properties of the cation [cis-Co(en)₂(NO₂)₂]⁺, which are found to have a pair of oppositely configured en rings [i.e., () or ()], we find that in1 the cations are in the lowest energy conformation and configuration; i.e., () or (). We attribute this change in configuration to the formation of strong interionic hydrogen bonds between nitrite anion oxygens and the axial—NH₂ hydrogens, which markedly weaken the intermolecular and intramolecular hydrogen bonds between ligand—NO₂ oxygens and the hydrogens of those same amine moieties. Thus, the nitrite anions behave exactly as nitrate anions, except that the hydrogen bonds found here are stronger than those formed by the latter. This is as expected since the negative charge is delocalized over two, instead of three, oxygens.     

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.     

Furanverbindungen, 11. Mitt.

Zusammenfassung Es wird über die Synthese einiger angulärer Furoxanthone mit einer Methylgruppe in -oder -Stellung oder einer Phenylgruppe in der -Stellung des Furanrings berichtet. Ausgegangen wurde von einem Hydroxyxanthon mit einem Orcinkern.

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The synthesis of a few angular furano-xanthones carrying a methyl group either in -or in -position or a phenyl group in the -position of the furan ring, starting with an hydroxy xanthone possessing an orcinol nucleus is recorded.

     

Saponins of dioscorea XV. Caucasosaponin and caucasoprosapogenin fromD. caucasica

Summary Two new saponins have been isolated from the rhizomes ofD. caucasica: the water-soluble caucasosaponin—a rhamnosotriglucoside of 25 D-22-spirost-22-en-3-ol—and the water insoluble caucasoprosapogenin—a glucosotrioside of 25 D-22-spirost-5-en-3-ol-, and also the previously known rhamnosidodiglucoside of 25 D-22-spirost-5-en-3-ol—gracillin.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 4, pp. 237–241, 1967     

The inclusion of non-nearest neighbor ß terms in pariser-parr-pople type S.C.M.O. calculations

The calculation of -electron properties by an S.C.M.O. method including all _core terms has been extended to nitrogen and oxygen containing systems. The singlet ^* electronic transitions and -ionization potentials (where available) are in reasonable agreement with experiment. A comparison is made with the non-empirical all electron calculations of Clementi for pyrrole, pyridine and pyrazine.

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Zusammenfassung Die Berechnung von -Elektronen-Eigenschaften mittels einer SCMO-Methode, die alle _core-Terme einschließt, wurde auf Systeme mit Stickstoff- und Sauerstoffatomen ausgedehnt. Die Singulett- ^*-Übergänge und -Ionisierungsenergien sind in vernünftiger Übereinstimmung mit dem Experiment. Es wird einen Vergleich mit den nichtempirischen Rechnungen mit allen Elektronen von Clementi an Pyrrol, Pyridin und Pyrazin angestellt.

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Résumé Le calcul des propriétés des électrons par une méthode S.C.M.O. tenant compte de tous les termes _coeur a été étendu aux systèmes contenant de l'azote et de l'oxygène. Les transitions électroniques singulet ^* et les potentiels d'ionisation (lorsqu'ils sont connus) sont en accord raisonnable avec l'expérience. Les résultats sont comparés aux calculs non-empiriques de tous les électrons effectués par Clémenti pour le pyrrole, la pyridine et la pyrazine.

     

Triterpene glycosides of alfalfa. IV. Medicoside J

A new triterpene glycoside has been isolated from the roots ofMedicago sativa L. (family Fabaceae) — medicoside J, and its structure has been established as a medicagenic acid 3-O--D-glucopyranoside 28-O-[O--D-xylopyranosyl-(1 4)-O--L-rhamnopyranosyl-(1 2)--L-arabinopyranoside].Institute of the Chemistry of Plant Substances of the Uzbek Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 610–613, September–December, 1986.     

George Martine,M.D., F.R.S. (1700–1741) an early thermal analyst?

A study of the life and work of George Martine, who seems to have been the first to have used the principle of differential thermal analysis, reveals that his stature scientifically (and perhaps medically) has not as yet been fully appreciated. A complete bibliography of his writings is appended.

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Zusammenfassung Durch das Studium von Leben und Werk von George Martine, der augenscheinlich der erste Anwender der Prinzipien der Differentialthermoanalyse war, wird offenkundig, daß sein Wesen bisher wissenschaftlich (und möglicherweise auch medizinisch) nicht gebührend gewürdigt wurde. Eine komplette Bibliographie seiner Schriften ist beigelegt.

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The author expresses his sincere gratitude to Mr R. N. Smart of the University of St. Andrews Library, Mr A. J. Clark, Deputy Librarian of the Royal Society, Mrs. J. Currie and Ms. J. Archibald of Edinburgh University Library, Dr. H. MacDonald of the National Library of Scotland, Ms. J. A. Beavan of Aberdeen University Library and all those contacted regarding the existence of a portrait of George Martine for their information and assistance, without which this article could not have been compiled.     

Studies on lanthanoid sulfites. Part VIII. Thermogravimetric study of europium sulfite trihydrate

When Eu₂(SO₃)₃·3H₂O is heated in air it forms after dehydration two sulfite-sulfate phases: Eu₂(SO₃)₂SO₂ and Eu₂SO₃(SO₄)₂. The latter phase is thermally remarkably stable and decomposes above 700°C via Eu₂O₂SO₄ to Eu₂O₃. Anhydrous Eu₂(SO₃)₃ and Eu₂O₂SO₄ were also found as intermediates before Eu₂O₃ when the TG experiments were carried out in nitrogen but in other details the decomposition mechanism differs from that in air.

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Zusammenfassung Eu₂(SO₃)₃·3H₂O bildet durch Erhitzen in Luft nach Dehydratation zwei Sulfit-Sulfat-Phasen: Eu₂(SO₃)₂SO₄ und Eu₂SO₃(SO₄)₂·Letztere ist thermisch bedeutend stabiler und zersetzt sich oberhalb 700°C über Eu₂O₂SO₄ zu Eu₂O₃. Bei Durchführung der TG-Experimente in Stickstoff wurden als Zwischenprodukte vor Eu₂O₃ auch wasserfreies Eu₂(SO₃)₃ und Eu₂O₂SO₄ gefunden, in anderen Details weicht jedoch der Mechanismus der Zersetzung von dem der Zersetzung in Luft ab.

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- Eu/SO_3/2SO₄ Eu₂SO₃/SO_4/2. 700° Eu₂O₃ Eu₂O₂SO₄. Eu₂/SO_3/3 Eu₂O₂SO₄ , .

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For Part VII, see ref. 6.     

Triterpene glycosides of alfalfa. II. Medicosides C

The roots of the plantMedicago sativa (family Fabaceae) have yielded, in addition to the medicoside G described previously, two more triterpeneglycosides, caulosaponin B and the new glycoside medicoside C. The latter has the structure of hederagenin 3-O-[-L-arabinoyranosyl-(1 2)--D-glucopyranosyl-(1 2)--L-arabinpyranoside].Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 805–808, November–December, 1985.     

S.C.F.M.O. study of Hafner's hydrocarbons

SCF MO calculations have been made for Hafner's hydrocarbons using neglect of differential overlap after the manner ofPople andPariser andParr. ^* transitions have been calculated by a limited configuration interaction method. The results show that agreement between predicted spectra and observed spectra is quite good for the heptalene derivative and reasonably good for the pentalene derivative. It is suggested that both molecules are aromatic in contradiction to predictions by Craig's rule.

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Zusammenfassung SCF MO-Rechnungen mit zero differential overlap nach der Methode vonPople, Pariser undParr wurden fürHafner's Kohlenwasserstoff angestellt. Mittels begrenzter Konfigurationswechselwirkung (wurden)die ^*-Übergänge berechnet, wobei die Ergebnisse im Fall des Heptalen-Derivates verhältnismäßig gut, in dem des Pentalen-Derivates jedoch nur ungefähr mit dem Experiment übereinstimmen. Darüber hinaus sprechen die Resultate im Gegensatz zur Craig'schen Regel dafür, daß beide Moleküle aromatischen Charakter haben.

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Résumé Nous avons effectué des calculs SCF MO pour les hydrocarbures deHafner, en négligeant le recouvrement différentiel d'aprèsPople etPariser etParr. Quelques transitions ^* ont été calculées par interaction de configurations limitée. L'accord avec l'expérience est assez bon pour le dérivé de l'heptalène, et raisonable pour le dérivé du pentalène. Les deux molécules semblent être aromatiques, contrairement à la règle de Craig.

     

Withasteroids of Physalis. X. Circular dichroism of withasteroids from plants of the genus Physalis

The circular dichroism method has been used to establish the stereochemical features of the structure of the withasteroids. The 22S-configuration of the asymmetric center has been confirmed for physangulide. The 22R-configuration has been confirmed for 14-hydroxyixocarpanolide, vamonolide, ixocarpanolide, 24,25-epoxywithanolide D, and withanolide T. On the basis of changes in the circular dichroism spectra in acid and alkaline media it is suggested that in compounds having a 4-hydroxy-1-oxo-5,6-epoxy-2,3-ene grouping the ^2,3 bond disappears, while in compounds having a 5-hydroxy-1-oxo-6,7-epoxy-2,3-ene grouping dehydration takes place at C-4-C-5. These characteristics can be used in the identification of the withasteroids. The isolation of withanolide T from the leaves ofPhysalis angulata L. is described and its spectral characteristics are given.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 371–376, May–June, 1990.     

Triterpenoid Glycosides of Scheffleropsis angkae. III. Structure of Glycoside L-I1

A new triterpenoid glycoside L-I ₁ , the 28-O--L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl ester of 3,23,27-trihydroxylup-20(29)-en-28-oic acid, is isolated from the leaves ofScheffleropsis angkae(Araliaceae). Its structure is established by chemical methods and various NMR techniques ( ¹ H, ¹³ C, APT, COSY, TOCSY, ROESY, HSQC, HMBC). 3,23,27-Trihydroxylup-20(29)-en-28-oic acid is a new triterpenoid aglycone     

Triterpene glycosides of Astragalus and their genins. XXIII. Cyclocanthogenin from Astragalus tragacantha

The epigeal part of the plantAstragalus tragantha Habl. (Leguminosea) has yielded (in addition to cyclosieversigenin, cyclocyclosiversioside F, and -sitosterol -D-glucopyranoside) a new methylsteroid of the cycloartane series — cyclocanthogenin — the structure of which has been established on the basis of chemical transformations and spectral characteristics, and also of a chemical correlation with the structure of cycloasgenin C, as 24S-cycloartane-3,6,16,24,25-pentaol.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 817–824, November–December, 1987.     

Steroid glycosides of the roots ofCapsicum annuum. II. The structure of the capsicosides

Two tigogenin glycosides and two diosgenin glycosides have been isolated from a methanolic extract of the roots of bush red pepper. An attempt to isolate the individual spirostanol glycosides directly was unsuccessful. These compounds have very similar structures. For their separation, acetylation and epoxidation of the double bond of the aglycon, diosgenin, in the corresponding glycosides was performed. The derivatives obtained were purified by chromatography. To establish the complete chemical structure of each capsicoside we used both chemical and physical methods; complete and partial acid hydrolysis, methylation followed by methanolysis, IR spectroscopy, mass spectroscopy, etc. It was shown that capsicoside A₂ is (25R)-5-spirostan-3-ol 3-O--D-galactopyranoside, capsicoside B₂ is (25R)-5-spirostan-3-ol 3-O-[O--D-glucopyranosyl(14)--D-galactopyranoside], capsicoside A₃ is (25R)-spirost-5-en-3-ol 3-O--D-galactopyranoside, and capsicoside B₃ is identical with funkioside C.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 242–246, March–April, 1987.     

Ferrocene Compounds. XXXI. Structure of 3-Ferrocenylpropanoic Acid

The title compound was prepared by modified procedure and characterized by means of IR, [¹H] and [¹³C] NMR spectroscopy. The structure was also determined by a single-crystal X-ray diffraction (XRD). 3-Ferrocenylpropanoic acid crystallizes as orange prisms in the triclinic space group P with a = 7.645(1) Å, b = 7.953(1) Å, c = 9.961(1) Å, = 81.67(1), = 68.43(1), = 83.76(1), V = 556.3(1) ų, Z = 2, R = 0.0435. In the ferrocene skeleton, Fe-C distances are in the range 2.033(2)–2.052(2) Å and C C distances in the range 1.412(5)–1.431(3) Å. The angle defined by ring centers and Fe atom is 177.7(1). The cyclopentadienyl rings are twisted from the eclipsed conformation by 8.3(2) (average value). In the structure was observed strong intermolecular hydrogen bond of 2.670(3) Å forming cyclic dimers of the R₂ ² (8) type.     

Reaction mechanisms in peptide synthesis. Part 2. Tautomerism of the peptide bond

Summary We had concluded in previous work that ring opening of a 2-alkyl-5(4H)-oxazolone by water or ammonia leads to transient high-energy imidol intermediates which instantly tautomerize to the native amides. Using the MOPAC molecular orbital program, detailed geometric and energetic characteristics of the tautomerism of a peptide bond have been determined on the AM1 level. The results demonstrate that tautomerism of a peptide bond comprises a three-stage process involving three successive transition states and a bimolecular mechanism: (i) EZ peptide bond isomerization followed by dimerization, (ii) concerted double-hydrogen exchange leading to an -hydroxyimine (imidic acid) followed by splitting of the dimer, and (iii) ZE N-methylimine inversion. While pathway (iiiiii) is predicted as a feasible route terminating in the formation of a peptide bond, the inverse route (iiiiii) is excluded as a possible initial step in the generation of a 5(4H)-oxazolone intermediate.