The crystal and molecular structure of the β-cyclodextrin inclusion complex with aspirin and salicylic acid

The crystal structure of the -cyclodextrin (-CyD) molecular complex with aspirin (acetylsalicylic acid), salicylic acid, and water, (C₄₂H₇₀O₃₅)₂ (C₉H₈O₄)₂ (C₇H₆O₃) 23.3H₂O, was determined by X-ray structure analysis. The crystal data is space group Pl, a=19.777(5), b=15.247(3), c=15.475(4) Å, =102.63(2)°, =116.96(2)°, =104.12(2)°, V=3729(2) ų, D_m=1.409(2) g/cm³, D_X=1.419 g/cm³, and Z=1. The two -CyDs form a dimer unit with hydrogen bond networks among the secondary hydroxyl groups of both -CyDs. This -CyD dimer includes three guest molecules of two different types in its hydrophobic cavity. Two of them are aspirin, which are separately included in each cavity of the -CyD unit, with their hydrophobic benzene rings protruding into the hydrophobic cavities of the host -CyDs. The remaining guest molecule is the hydrolyzed product of an aspirin, that is salicylic acid, which is sandwiched in the space constructed by the -CyD dimer formation, and is statistically disordered at three sites.     

Culcitosides C2 and C3 from the starfishCulcita novaeguineae

Two steroid glycosides not previously described have been isolated from the digestive system of the starfishCulcite novaeguiniae, and these have been called culcitosides C₂ and C₃. With the aid of chemical and spectral methods, the chemical structure of C₂ has been established as 24-methyl-5-cholestane-3,4,6,8,15,16,28-heptaol 28-O-[O-(2,4-di-O-methyl--D-xylopyranosyl)-(1 2)--L-arabinofuranoside, and that of C₃ as its 4-deoxy analogue.Pacific Ocean Institute of Bioorganic Chemistry of the Far Eastern Scientific Center of the USSR Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 592–596, September–October, 1986.     

Radiation-induced reactions of cholesterol in an aqueous medium

⁶⁰Co -ray radiolysis of cholesterol /3-hydroxy-5-cholestene/ /I/ in the two-phase system /water-ethyl acetate/ and in the presence of air has been studied using TLC and GC methods. The following products were observed in the irradiated mixture: 3, 7-dihydroxy-5-cholestene /II/, G O. 36, 3-hydroxy-7-keto-5-cholestene /III/, G 1.48, 3-hydroxy-7-keto-5-cholestane /IV/, G 0.22, 3,5,6-trihydroxy-5-cholestane /V/, G 0.83, 5,6-epoxy-3-hydroxy-5-cholestane /VIa/, G 0.26, 5,6-epoxy-3-hydroxy-5-cholestane /VIb/, G 0.24, and 2, 3-dihydroxy-5-cholestene /VII/, G 0.22. The dose dependence of the formation of these products shows that the cholesterol derivatives substituted in the position 7 /II–IV/ are formed from a common precursor — the radical Ia. On the other hand, the products of the 5–C=C double bond reactions /V and VI/ are formed independently. Also the product VII is formed independently. A reaction scheme that is in agreement with these results is proposed.     

Crystal and molecular structures of the sesquiterpene lactone ajafinin

An x-ray structural analysis has been made with the aim of reliably determining the spatial structure of the sesquiterpene lactone ajafinin. It has been established that it has the structure and configuration of 1,2--epoxy-3,4,10-trihydroxy-5,6(H),7(H)-guai-11(13)-en-6,12-olide.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 291–295, May–June, 1986.     

New polyhydroxysteroids from the far-eastern starfish Henricia sp.

From the far-eastern starfishHenricia sp. we have isolated and characterized the new polyhydroxysteroid (24S)-5-cholestane-3,4,6,8,15,24-hexaol and three new glycosides: (24S)-5-cholestane-3,4,6,8,15,24-hexaol 3-O-(2,4-di-O-methyl--D-xylopyranoside) (henricioside H₁), 24-methyl-5-cholesta-4,22E-diene-3,6,8,15,16,26-hexaol 3-O-(2,3-di-O-methyl--D-xylopyranoside) (henricioside H₂), and the 22,23-dihydro derivative of henricioside H₂ (henricioside H₃).Pacific Ocean Institute of Bioorganic Chemistry, Far-Eastern Scientific Center, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 249–253, March–April, 1993.     

Glycosides of marine invertebrates. Structure of holothurin A2 from the holothurianHolothuria edulis

The structure of a new glycoside fromHolothuria edulis, holothurin A₂, has been established with the aid of periodate oxidation, methylation, Smith degradation, and¹³C NMR spectroscopy. The structure of the glycoside has been determined as holost-9(11)-ene-3,12,17-triol 3-0-{2-0-[3-0-methyl--D-glucopyranosyl-(13)-0--D-glucopyranosyl-(14)-0--D-quinovopyranosyl]-4-0-sulfate--D-xylopyranoside}.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 215–219, March–April, 1982.     

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.     

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 1,2,3,14,20R,22R,24,25-octahydroxy-5--cholest-7-en-6-one.Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii. No. 4, pp. 522–525, July–August, 1985.     

Die γ-Bestrahlung von synthetischem β-Carotin

Zusammenfassung Das feste -Carotin ist gegen -Strahlung ziemlich stabil. Bei Bestrahlung unter Sauerstoffbegasung treten deutliche -Carotin-Verluste erst bei der hohen Dosis von 12 Mrad auf; bei Bestrahlung an der Luft werden ähnliche Radiolyseerscheinungen erst durch wesentlich höhere Strahlendosen ausgelöst. Spaltungsprodukte, die bei 12 Mrad und Sauerstoffbegasung auftraten und dünnschichtchromatographisch aufgetrennt werden konnten, waren Isozeaxanthin, -Carotin-5,6-5, 6-diepoxid, -Carotin-5,8-5,8-diepoxid, -Apo-12-carotinal, -Apo-10-carotinal, 3,3,6-Trihydroxy--carotin-5,8-epoxid und Vitamin-A-Alkohol. Es ist bemerkenswert, daß ein Teil der Radiolyseprodukte (z. B. Vitamin-A₁-Alkohol, -Apo-12-carotinal und -Apo-10-carotinal) Vitamin-A-Wirksamkeit besitzt.

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The -Irradiation of synthetic -carotene. Some physico-chemical and thin-layer chromatographic studies of radiolysis products

Solid -carotene is remarkably stable to -irradiation. In an oxygen atmosphere doses as high as 12 Mrad were required to bring about significant losses of -carotene, whereas in air even larger doses had to be applied in order to effect a comparable degree of radiolysis. Cleavage products which arose in O₂ at a dose of 12 Mrad and which could be separated from each other by thin-layer chromatography were isozeaxanthin, -carotene-5,5-5,6-diepoxide, -apo-12-carotenal, -apo-10-carotenal, 3, 3, 6-trihydroxy--carotene-5,8-epoxide and vitamin A₁. It is notable that some of the radiolysis products (e.g., vitamin A₁, -apo-12-carotenal and -apo-10-carotenal) possess vitamin A activity.

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Herrn Prof. Dr.O. Hromatka zum 65. Geburtstag gewidmet.     

Glycosides of marine invertebrates. XIII. New holothurinogenins of holothurin B1 fromHolothuria floridana

We have isolated for the first time the native aglycone of a triterpene glycoside of the holoturin series — holothurin B₁ — and have established its structure as holost-9-ene-3,12,17-triol. The structures of two new holostane derivatives have been established — holosta-8,11-diene-3,17-diol and 3,17-dihydroxyholost-9-en-12-one. A scheme of transformation of the native genin of holothurin B₁ under the conditions of the acid splitting of the glycoside has been put forward.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 323–327, May–June, 1982.     

Phase solubility analysis in studying the interaction of nifedipine with selected cyclodextrins in aqueous solution

The solubilizing potential and complexing tendencies of six cyclodextrins (CyD) with nifedipine in aqueous solution were evaluated using phase solubility methods. Solubility curves of nifedipine with -CyD, 2-hydroxypropyl--CyD (2HP--CyD) and 2-hydroxypropyl--cyclodextrin (2HP--CyD) were classified as type A_L, while for heptakis (2,6-dimethyl)--CyD (DIMEB), randomly methylated--CyD (RAMEB) and -CyD, A_p type phase behaviour was observed. Stability constants, calculated from phase solubility diagrams, decreased in the order: DIMEB > RAMEB > -CyD > 21HP--CyD > -CyD > 2HP--CyD.     

The role of intra- and intermolecular hydrogen bonds in the formation of β-cyclodextrin head-to-head and head-to-tail dimers. The results of ab initio and semiempirical quantum-chemical calculations

The conformation of a free -cyclodextrin molecule optimized by the MNDO/PM3 quantum-chemical calculations has C₇ symmetry. The right orientation of the interglucose hydrogen bonds in -cyclodextrin, in which the 2-OH groups act as the proton donors and the O atoms of the nearby 3"-OH groups function as the proton acceptors, is advantageous for thermodynamic reasons. The ring of seven H bonds thus formed stabilizes the symmetrical form of -cyclodextrin. The -cyclodextrin head-to-head dimer has D ₇ symmetry and consists of molecules whose 2-OH groups partcipate as proton donors in the formation of fourteen complementary intermolecular hydrogen bonds. The energy of H bonds in the -cyclodextrin monomer and dimer was estimated to be 1.0--1.4 kcal mol^–1. Of the two possible -cyclodextrin dimers, the head-to-tail dimer is more thermodynamically stable. The thermodynamic preference of the right orientation of the inter-glucose H bonds in -cyclodextrin was confirmed by the MP2/6-31G(d,p)//6-31G(d,p) ab initio calculations for maltose (-glucodioside). The maltose molecule with inter-glucose H bonds of the type 2-OHO(3")-H is more stable than the structure with the H-(2)OH-O(3") orientation of H bonds with a difference of 2.7 kcal mol^–1. According to the MNDO/PM3 method, the maltose structure with the right H bond orientation is more stable by 3.1 kcal mol^–1.     

Rearrangement ofα -trifluoromethyl-β-dialkylamino-β-fluoroacrylic acid N.N-dialkylamides

Conclusions When heated in the presence of a catalytic amount of BF₃ etherate,-trifluoromethyl--diethylamino--fluoroacrylic acid N, N-dimethylamide is reversibly isomerized to-trifluoromethyl--dimethylamino--fluoroacrylic acid N, N-diethylamide. The methyl esters of-trifluoromethyl--diethylammo--fluoroacrylic acid and-trifluoromethyl--phenoxy--fluoroacrylic acid N,N-dimethylamide are not isomerized under the same conditions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.1, pp.137–141, January, 1976.     

Übergangsmetall-Chalkogensysteme, 3. Mitt.: Das System Nickel-Tellur

Zusammenfassung Auf Grund thermischer und röntgenographischer Unter-suchungen wurde das vollständige Phasendiagramm Ni–Te aufgestellt. Die Anlage für die thermische Analyse wurde teilweise automatisiert, so daß ausgewählte Temperaturintervalle mit einstellbaren Heiz- udn Kühlgeschwindigkeiten periodisch durchlaufen werden konnten. Zwischen Ni und der kub. f. z. Hochtemperaturphase ₁ (Ni_3±x Te₂) liegt ein Eutektikum bei 34 At% Te und 1004,5°C. ₁ schmilzt kongruent bei 38 At% Te und 1021,5°C und hat eine maximale Phasenbreite von 37 At% Te (1004,5°C) bis 43,5 At% Te (880°C). Nickelreiches ₁ wandelt sich zwischen 796 und 789°C in eine Ordnungsphase ₁ um, die bei 37,7 At% Te und 731°C eutektoidisch in Ni und ₂ zerfällt. ₁ und ₁ wandeln sich unterhalb bei 790°C in die tetragonale ₂-Phase um, deren maximaler Homogenitätsbereich von 38,8 At% Te (731°C) bis 41 At% Te (775°C) reicht. Bei 42,5 At% Te und 775°C zerfällt ₁ eutektoidisch in ₂ und ₂. Die ₂-Phase (NiTe_0,85) bildet sich peritektisch bei 880°C und zerfällt bei 690°C nach _{2 1} + . Orthorhombisches ₁ disproportioniert sich peritektoidisch bei 742,5°C in ₂ und ₂. ₂ bildet bei 873°C und 49,5 At% Te ein Eutektikum mit der -Phase vom NiAs-Typ. hat einen kongruenten Schmelzpunkt von 900,5°C bei 56 At% Te und eine maximale Phasenbreite von 52 At% Te (690°C) bis 66,6 At% Te (448,5°C). Mit Te bildet die -Phase ein entartetes Eutektikum bei 448,5°C. Die Phasen ₂, ₁ und wurden röntgenographisch verifiziert und die Abhängigkeit der Gitterparameter der -Phase von der Konzentration vermessen.

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Transition metal-chalcogene systems, III: The system Ni–Te

Based on thermal and X-ray measurements the complete Ni–Te phase diagram was constructed. The equipment for thermal analysis was partially automated so that selected temperature intervals could be periodically scanned by programmed heating and cooling rates. Between Ni and thefcc high temperature phase ₁ (Ni_3±x Te₂) a eutectic exists at 34 at% Te and 1004.5°C. ₁ melts congruently at 38 at% Te and 1004.5°C, and has a maximum phase width from 37 at% Te (1004.5°C) to 43.5 at% Te (880°C). Nickel-rich ₁ transforms between 796 and 789°C into an ordered phase ₁ which decomposes eutectoidally into Ni and ₂ at 37.7 at% Te and 731°C. ₁ and ₁ transform at temperatures below 790°C into the tetragonal ₂-phase which has a maximum range of homogeneity from 38.8 at% Te (731°C) to 41 at% Te (775°C). At 42.5 at% Te and 775°C ₁ decomposes eutectoidally into ₂ and ₂. The ₂-phase (NiTe_0.85) is formed by the peritectic reactionL + _{1 2} at 880°C and decomposes at 690°C according to _{2 1} + . Orthorhombic ₁ disproportionates peritectoidally at 742.5°C into ₂ and ₂. ₂ forms at 873°C and 49.5 at% Te a eutectic with the -phase of the NiAs-type. has a congruent melting point of 900.5°C at 56 at% Te and a maximum phase width from 52 at% Te (690°C) to 66.6 at% Te (448.5°C). Te and the -phase form a degenerate eutectic at 448.5°C. The phases ₂, ₁, and were verified by X-ray diffraction and the lattice parameters of the -phase were determined as a function of concentration.

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Mit 2 Abbildungen     

Oligomeric proanthocyanidin glycosides ofRhodiola pamiroalaica. II

In a continuation of investigations of proanthocyanidins of the roots ofRhodiola pamiroalaica, we have isolated proanthocyanidins RP-3 and RP-4. Their compositions, structures, and relative configurations have been investigated: RP-3 is 7-O-(6-O-galloyl--D-Glcp)-3-O-galloyl-(-)-epigallocatechin-(4-8)-[(-)-epicatechin-(4-8)-(3-O-galloyl-(-)-epigallocatechin)]₂-(4-8)-[5-O-(-D-GlcpO--D-Glcp)-(+)-catechin], and RP-4 is 7-O-(6-O-galloyl--D-Glcp-3-O-galloyl-(-)-epigallocatechin-(4-8)-[3-O-galloyl-(-)-galloyl-5-(-D-GlcpO--D-Glcp)-(-)-epigallocatechinTranslated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 42–49, January–February, 1999.     

Structures of some lilioglycosides from the bulbs ofLilium regale

Six steroid glycosides, which gave been called lilioglycosides B, C, E, F, H, and I have been isolated from fresh bulbs ofLilium regale Wills. The structure of each compound has been determined by methods of physicochemical analysis. This is the first time that lilioglycosides B, C, H, and I, have been described; they are, respectively: (25S)-spirost-5-ene-3,27-diol3-O--D-glucopyranoside; (25R)-spirost-5-ene-3,27-diol3-O--D-glucopyranoside27-(3-hydroxy-3-methylglutarate); (25S)-spirost-5-ene-3,27-diol3-O-{[O--L-rhamnopyranosyl-(12)],[O--D-glucopyranosyl-(13)]--D-glucopyranoside}; and (25S)-spirost-5-ene-3,27-diol 3-O-{[O--L-rhamnopyranosyl-(12)],[O--D-glucopyranosyl-(13)]-O--D-glucopyranoside} 27-[(S)-3-hydroxy-3-methylglutarate].Institute of Genetics, Academy of Sciences of the Republic of Moldava, 2002, Kishinev, ul. Padurilor, 20. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 841–847, November–December, 1997.     

Molecular Interactions and Inclusion Phenomena in Substituted β-Cyclodextrins. Simple Inclusion Probes: H2O, C, CH4, C6H6, NH4 +, HCOO−

Using a simple molecular mechanics approach interaction energy profiles of simple probes (C, CH₄, C₆H₆, H₂O, NH₄ ⁺, and HCOO^-) passing through the center of the -CD ring cavity along the main molecular symmetry axis were first evaluated. Molecular Electrostatic Potential (MEP) values along the same path were also evaluated. The effect of the flexibility of the host -CD molecule together with solute-solvent (H₂O) interactions have been represented by averaging structures of MD calculations for -CD alone and -CD surrounded by 133 H₂O molecules. The effect of various substitutions of -CD has also been evaluated. Small symmetric hydrophobic probes (such as C, CH₄, C₆H₆) are predicted to form stable inclusion complexes with non-substituted and substituted -CDs, the probe position typically being near the cavity center. The stability of the inclusion complexes will increase with increasing size and aliphatic character of the probe. Small polar and charged probes (such as H₂O, NH₄ ⁺, HCOO^-) are predicted to prefer the interaction with the solvent (water) in the bulk phase rather than the formation of inclusion complexes with non-substituted and substituted -CDs. Guest–host interactions in the stable inclusion complexes with hydrophobic probes are almost entirely dominated by dispersion interactions. The MEP reaches magnitudes close to zero in the center of the non-substituted -CD ring cavity and in most of the studied substituted -CDs and shows maximum positive or negative values outside of the cavity, near the ring faces. Substitution of -CD by neutral substituents leads to enhanced binding of hydrophobic probes and significant changes in the MEP profile along the -CD symmetry axis.     

The effects of cyclodextrin inclusion of the ferrocenemonocarboxylate anion on the kinetics of its oxidation by bis(pyridine-2,6-dicarboxylato)cobaltate(III) in aqueous solution

The effects of -, -, dm-(heptakis(2,6-di-O-methyl)--) and -cyclodextrins (CD) on the kinetics of the electron-transfer reaction of the ferrocenemonocarboxylate anion (FCA^–) with bis(pyridine-2,6-dicarboxylato)cobaltate(III) have been investigated in aqueous solution (0.20 M Na₂HPO₄, pH 9.2) at 25.0°C. Substantial decreases in the rate constants for the electron-transfer reactions were observed upon cyclodextrin inclusion of the reductant, due to an increase in the FCA^0/– reduction potential and to the insulation of the reductant from oxidant. The inclusion stability constants for {FCA·CD}^– were evaluated from the¹H NMR and kinetic data, and the order of the stability constants was found to be -CDdm-CD-CD>-CD.     

Triterpene glycosides of Hedera taurica. IV. Structure of hederosides A1, A2, D1, and D2 from the berries of Crimean ivy

New triterpene glycosides have been isolated from the berries of Crimean ivyHedera taurica Carr. (family Araliaceae) — hederoside A₁ (methyl ester of 3-O--D-glucopyranosylhederagenin) and hederoside D₁ 3-O-[O--D-glucopyranosyl]-(12)--D-glucopyranosyl]hederagenin and also the known glycosides 3-O--D-glucopyranosyloleanolic acid and 3-O-[O--D-glucopyranosyl-(12)--L-arabinopyranosyl]hederagenin. The structures of these compounds were established on the basis of the results of chemical methods and¹H and¹³C NMR spectroscopy.M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 228–230, March–April, 1990.     

Steroids of the spirostan and furostan series from plants of the genus Allium. XXVII. Alliosterol and allosides A and B from Allium suvorovii and Allium stipitatum — Structural analogs of furostanols

Two new glycosides of the cholestane series (allosides A and B) have been isolated from the fruit of the cocultivatedAllium suvorovii Rgi. andAllium stipitatum Rgl. (family Liliaceae, local name anzur). The acid hydrolysis of both compounds gave a sterol not previously described, which has been called alliosterol and has the structure of (22S)-cholest-5-ene-1, 3, 16, 22-tetraol, and the product of its dehvdration, which is (16S, 22S)-furost-5-ene-1, 3-diol. Alloside A is the 16-O--D-galactopyranoside, and alloside B the 16-O--D-galactopyranoside 1-O--D-glucopyranoside of alliosterol.Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 231–241, March–April, 1991.