Synthesis of 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl esters of acids with phytohormonal activity. New modification of the koenigs-knorr method

2,3,4,6-Tetra-O-acetyl--D-glucopyranosyl esters were synthesized by the reaction of tetralkylammonium salts of 4-amino-3,5,7-trichloropicolinic, 2,4-dichlorophenoxyacetic, and -indolylacetic acids with 2,3,4,6-tetra-O-acetyl--D-glucopyranosyl bromide. According to the PMR spectral data, substitution occurs stereospecifically to give the anomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1374–1375, October, 1981.     

Experimental study of particle-to-liquid mass transfer in two-phase fixed and fluidized beds

Primary experimental results for local particle-to-liquid mass transfer in two-phase fixed and fluidized beds and in free flows are reported. A hypothesis on the mechanism of the effect of turbulent pulsations is suggested.

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Discrimination between catalyst deactivation mechanisms by kinetic measurements in open systems

Two competitive mechanisms of catalyst deactivation caused by either the starting substance or the reaction product are considered. The problem of the possible discrimination between these mechanisms according to kinetic measurements in open systems can be solved by a numerical experiment on a computer.

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— , . , . .

     

Conversion of methanol to hydrocarbons over metal-zeolite catalysts

Ni²⁺, Cr³⁺ and Pb²⁺ exchanged CaY zeolites including mixed forms like CrNiCaY and PbNiCaY were used to study methanol conversion. The selectivity of the reaction to olefin and paraffin formation depends on the type of samples, the activation of the catalyst and the reaction conditions.

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CaY , Ni²⁺, Cr³⁺ Pb²⁺- , CrNiCaY PbNiCaY, . - , .

     

Preparation of micron-size monodisperse polymer microspheres having chloromethyl group

Micron-size monodisperse polymer microspheres having chloromethyl groups thereon were prepared by two-step polymerization process as follows. First, micron-size monodisperse polystyrene particles were prepared by dispersion polymerization with 2,2-azobisisobutyronitrile as initiator in ethanol-water medium in the presence of poly(acrylic acid) as stabilizer under various conditions. Secondly, in the presence of the 1.9-m monodisperse polystyrene particles produced under the optimum conditions, seeded copolymerization for styrene and chloromethyl styrene was carried out. The seeded copolymerization proceeded smoothly without producing new particles, and it was confirmed by x-ray photoelectron spectroscopy that the chloromethyl group existed more at the surface of the produced microsphere than at that of film cast from the benzene solution in which the microspheres were dissolved.Part CVI of the series Studies on Suspension and Emulsion.     

Floroselin, a new coumarin from the roots of Seseli sessiliflorum

Conclusions A new coumarin has been isolated from the roots ofSeseli sessiliflorum for which the structure of 3-angeloyloxy-2,2-dimethyl-4-(trans-3-methylthioacryloyloxy)-3, 4-dihydropyrano-5,6:8,7-coumarin has been proposed. This is the first time that esters of 3-methylthioacrylic acid have been found in the coumarin series.All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 517–521, September–October, 1970.     

Kinetics and mechanism of the interaction of DL-methionine with cis-diaquaethylenediamine platinum(II) perchlorate in aqueous medium

The kinetics of the interaction of DL-methionine with [Pt(en)(H2O)2]2+ have been studied spectrophotometrically as a function of [Pt(en)(H2O)22+], [DL-methionine], PH and temperature. The reaction proceeds via a rapid outer sphere association followed by two slow consecutive steps having first order dependence on the aqua ion and methionine concentrations. Activation parameters have been evaluated using the Eyring equation. The low H1 (15.6 kJ mol–1) and large negative value of S1 (–230 J K–1 mol–1) as well as H2 (19.5 kJ mol–1) and S2 (–226 J K–1 mol–1) indicate an associative mode of activation for both the aqua ligand substitution processes in the two consecutive steps.     

Spectroscopic investigation of cyclodextrin monomers,derivatives, polymers and azo dyes (1)

Circular dichroism (CD) and visible spectra of inclusion compounds between Methyl Orange (MO) analogues and -, -, -cyclodextrin (cdx), 2,6-dimethyl-and 2,3,6-trimethyl--cdx, water soluble -, -, -cdx polymer products were investigated. In the CD-spectroscopic investigation, the complex with -cdx epichlorohydrin condensate showed a large amplitude and splitting of the induced ^* band. Fractions of glyceryl ether of less than 2000 and polymer of more than 10000 dalton molecular mass were separated. Complexes of above two fractions and MO showed the same splitting spectral pattern. Job's plots from visible spectra showed the formation of the 11 complex and CD-data suggested the co-existence of the 21 MO-cdx complex. This splitting pattern showed the reversal of the signs when -cdx-ethyleneglycol-bis(epoxypropyl) ether was used and disappeared when larger host molecules and azo dyes were used. The splitting was explained by exciton interaction.     

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.     

The mass spectra of 10,10-dimethyl-9,10-dihydro-10-sila-2-azaanthracenes with heterocyclic substituents at C9

The major pathways for the fragmentation of dihydrosilaazaanthracenes, containing an azetidine substituent, spiro--lactam ring, or spirotetrahydrofuryl residue at C⁹ upon electron impact are related to the presence of these rings. The azetidine ring may be eliminated as a radical or by splitting in half to give [M-Me]⁺ ions. Splitting of the spiro--lactam ring in half leads to the two strongest ions M⁺. The loss of the tetrahydrofuryl ring leads to ions of 9-methylene- and 9-oxosilaazaanthracenes. The dlmethylsilyl group loses a methyl radical at various stages of the decomposition.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1182–1185, May, 1990.     

Steroid glycosides XXI. The structure of polygonatoside E′ and protopolygonatoside E′ from the leaves ofPolygonatum latifolium

Summary The chemical structures of two new steroid glycosides from the leaves ofPolygonatum latifolium have been shown. Polygonatoside E is 3-[0--D-glucopyranosyl-(1 3)-0--D-glucopyranosyl-(1 4)-0--d-galactopyranosyl-(1 3)--D-glucopyranosyloxy]-(25R)-spirost-5-ene, and protopolygonatoside E is 26--D-galactopyranosyl-(1 3)--D-glucopyranosyloxy]-(25R)-furost-5-en-22-ol.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kishenev. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 350–354, May–June, 1978.     

Oxidative coupling of 5-membered heterocyclic compounds catalyzed by palladium(II)

Coupled heterocycles (bithiophenes, bifurans, furyl thiophenes) have been obtained in high yields via the reaction of thiophene and furan with palladium salts in solution at 50–100°C.

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50–100° (, , ) .

     

Glycosylation of triterpene alcohols of the lupane series

The glycosylation of lupeol, allobetulin, 3-28-dihydroxy-18-lupene, 3-28-dihydroxy-18, 19-epoxylupane and of betulin monoacetates in acetonitrile with mercury cyanide has been studied. The 3- and 28-mono- and the 3,28-di-O--D-glucopyranosides of 3-28-dihydroxy-18-lupene and of 3-28-dihydroxy-18, 19-epoxylupane have been synthesized for the first time. Preparative methods for the synthesis of glucosides of lupeol, of allobetulin, and of betulin 3- and 28-monoacetates are proposed.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 212–217, March–April, 1988.     

Studies of the reactions of Br(2P3/2) and Br(2P1/2) with SiH4

Photobromination of SiH₄ under uv-irradiation at various wavelengths has been studied. Rate constants for the elementary reactions Br(²P_3/2)+SiH₄HBr+SiH₃ (k=3.2×10^–11 exp(–21.8±2.5)/RT, cm³/s) and Br^* (²P_1/2)+SiH₄HBr+SiH₃ (k^*=(3±1)×10^–13 cm³/s) have been determined in the temperature range from 300 to 415 K.

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- . Br(²P_3/2)+SiH₄HBr+SiH₃, k=3,2×10^–11 exp (–21,8±2,5)/RT ³/ Br^*(²P_1/2)+SiH₄HBr+SiH₃, k^*=(3±1)×10^{–13 3}/ 300–415 K.

     

Studies on the V2O5?TiO2 system, V. Equilibrium pressures

The oxygen equilibrium pressures from pure V₂O₅ and co-precipitated V₂O₅–TiO₂ system were measured in the range of 200–450 °C. The behavior of the equilibrium pressure with changes of temperature of the samples with and without TiO₂ is attributed to Ti⁴⁺ interaction with the V₂O₅ lattice.

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V₂O₅ - V₂O₅–TiO₂ 200–450°C. TiO₂ Ti⁺⁴ V₂O₅.

     

Thermal Investigation of 1,2-propanediamine complexes of nickel(II) in the solid phase

Thermal studies have been carried out on [NiL₃]X₂·n H₂O, whereL=1,2-propanediamine;X=Cl^–, Br^–, SCN^–, 1/2SO ₄ ^2– and 1/2 SeO ₄ ^2– ; andn= 2, 1.5 and 0. [Ni₂L₅(NCS)₂](SCN)₂ and [NiL₂SO₄] have been synthesized pyrolytically in the solid-state from their mother diamine complexes. The deaquation behaviour of [NiL₃]SO₄·2 H₂O appears interesting, and its monohydrate undergoes a solid-state reaction (88–102°) without mass loss, showing an exothermic peak at 95 °C (H=– 5.1 kJ mole^–1).

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Zusammenfassung Thermische Untersuchungen wurden an [NiL₃]X₂,n H₂O ausgeführt, wobeiL-1,2-Propandiamin;X=Cl^–, Br^–, SCN^–, 1/2 SO ₄ ^2– und 1/2 SeO ₄ ^2– ;n=2, 1.5 und 0. [Ni₂Ls(NCS)₂](SCN)₂ und [NiL₂SO₄] wurden ausgehend von den entsprechenden Diaminkomplexen pyrolytisch im festen Zustand synthetisiert. Das Dehydratisierungsverhalten von [NiL₃]SO₄·2 H₂O scheint interessant zu sein, und beim entsprechenden Monohydrat wird eine ohne Massenverlust verlaufende Festkörperreaktion (88–102°) beobachtet, die sich durch einen exothermen Peak bei 95 °C (H=– 5.1 kJ mol^–1) zu erkennen gibt.

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[N³L₃]₂· n₂O, L=1,2-,=l^–, Br^–, SCN^–, 1/2 SO ₄ ^2- , 1/2SeO ₄ ^2- , an=2, 1.5 0. [Ni₂L₅(NCS)₂](SCN)₂ [NiL₂SO₄] . [N³L₃]S₄·2 ₂ , 88–102° , 95 ° =– 5.1 ·^–1.

     

Biosynthesis of asterosaponins from cholesterol and other sterols under the conditions ofin vitro homogenates of starfish gonads and pyloric ceca

Conditions have been selected for performing thein vitro biosynthesis of asterosaponins from cholesterol and other sterols in homogenates and cultures of the gonads and pyloric ceca of Far Eastern starfish. It has been shown that the aglycone moiety of an asterosaponin can be biosynthesized from cholesterol, cholesterol sulfate, 5-cholestanol, and 3,6-dihydroxy-5-cholestane but not from 3, 6-dihydroxy-5-cholestane. Of the give precursors studied, cholesterol was transformed into asterosaponins most completely.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 663–667, September–October, 1985.     

Reaction of trans-tetracyanodioxomolybdate(IV) with salicylaldehyde as an important stage in the Schiff base ligand formation. Kinetics and mechanism

The kinetics of the reaction between the protonated species of trans-[Mo(CN)4O2]4– and salicylaldehyde (Hsal) was studied in the 7.8–12.0 pH range in H2O-MeOH mixtures. Spectroscopic characterization of the product indicates that the aqua and cyano ligands are substituted by sal– with formation of the [Mo(CN)3O (sal- 2O,O)]2– ion. The formation quotient, Kf for the overall reaction=31 (±1) at 25°C. In the presence ofan excess of ligand, the rate law is of the formd[Mo(CN)3O(sal- 2O,O)2–]/dt =kobs[Mo(CN)4O (H2O)2–]. The kobs value is equal to 2.9 (±8)×10–3 at 25°C. The activation parameters H (kobs) and S (kobs) are 103 (±9)kJmol–1 and 45 (±8)JK–1mol–1, respectively. The amount of the product formed decreases with increasing pH but the rate of the product formation increases. The reaction mechanism and the possible formation of Schiff base ligands in the presence of amines are discussed.     

51V NMR studies of systems V2O5-KHSO4 and V2O5?K2SO4

Systems V₂O₅–KHSO₄ and V₂O₅–K₂SO₄ have been studied by the⁵¹V NMR method. The first system demonstrates the same states of vanadium as the previously studied V₂O₅–K₂S₂O₇, in this system a compound with an equimolar ratio of components has been found. In V₂O₅–K₂SO₄ the state of vanadium differs from the above systems and the formation of a compound with V/K=4 is observed.

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⁵¹V KHSO₄–V₂O₅ K₂SO₄–V₂O₅. , K₂S₂O₇–V₂O₅, . K₂SO₄–V₂O₅ V/K4.