Synthesis and Dehydrohalogenation of 3 β-Chloro-5 α,7 α-dibromo-6-ketosteroids of the Stigmastane and Cholestane Series

3-Chloro-5,7-dibromo-6-ketosteroids 5a and 5b are synthesized from -sitosterol (1a) and cholesterol (1b). Dehydrohalogenation of these forms 7-bromo-2,4-dien-6-ones (6a-b), 2,4-dien-6-ones (7a-b), and 14-hydroperoxy-2,4,7-trien-6-ones (8a-b). Woodward hydroxylation of dienone 6a produces 2-iodo-7-bromo-3-acetoxy-⁴-6-ketone 9 and 7-bromo-2,3-diacetoxy-⁴-6-ketone 10. 2-Iodo-3-acetoxy-^4,7,14-trien-6-one 11 is prepared analogously from trienone 8a.     

Acidity and catalytic activity of polyfunctional zeolite catalysts in the benzene-propene-diisopropylbenzene system

Studies on the effect of the acidity of polyfunctional zeolite catalysts on their activity in benzene alkylation by propene and its transalkylation by diisopropylbenzene (DIPB) have revealed that alkylation and transalkylation of aromatics proceed on catalytic centers of different acidity.

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. , .

     

Synthesis of chromenes with isoprenoid side chains and their selective ozonolysis

The reactions of trimethylhydroquinone with isoprenoid allylic alcohols catalyzed by a Pentasil type zeolite in the H-form gave trimethyl-1,4-benzoquinones with the corresponding isoprenoid group, which were subsequently transformed into the target ³-chromenes on treatment with pyridine. Partial ozonolysis of chromenes proceeded selectively at the -bond of the side chain, resulting in the corresponding chromenes with an -carbonyl group.     

Transmethylation of trimethylbenzenes and toluene on H- and Ni/H-mordenites

Under pressure in the presence of hydrogen the calculated transmethylation equilibrium composition was approached on synthetic H-mordenite at 350°C, on natural H-mordenites at 450–500°C. The high activity of H-mordenite is maintained without deactivation by using the reduced Ni, H-form of synthetic mordenite with a nickel content of 2.4 mass %.

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- 350°C - 450–500°C. - , Ni, - 2,4 . %

     

Structure-Activity Relationship of Insecticidal Steroids. IV. 3β-Chlorosubstituted Derivatives of Cholesterol and β-Sitosterol

The toxicity of 3-chlorosteroids 1-8 for colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by a contact-intestinal method. The most active insect growth and development regulators of the studied compounds are 3-chlorocholest-5-ene (1a), 3-chloro-5,6-diol 6-formate (3b), 3-chloro-7-hydroxy-6-ketone (4a), and 3-chloro-5-bromo-⁴-6-ketone (8).     

Reaction of Pregnenolone and 3α,5-Cyclo-5α-pregnan-6β-ol-20-one with Trifluoroperacetic Acid

The reaction of pregnenolone and 3,5-cyclo-5-pregnan-6-ol-20-one with trifluoroperacetic acid produces the trifluoroacetates, hydrolysis of which gives the 3,5alpha;,6-triol.     

Oxidation of L-sorbose and 2,3;4,6-di-O-isopropylidene-α-L-sorbose over supported platinum and palladium catalysts

Oxidation of L-sorbose and 2,3;4,6-di-O-isopropylidene--L-sorbose by oxygen (air) has been studied over supported Pt and Pd catalysts. The results indicate that the activity and stability of these catalysts are greatly dependent on their composition and preparation conditions.

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L- 2,3;4,6--O---L- () . , .

     

Etude thermoanalytique de quelques steroides I — Monovalerianate d'estradiol et estriol

A thermoanalytical study of estradiol monovalerate (a) and estriol (b) revealed the thermal stability, the decomposition kinetics, and the temperatures and intervals of fusion. The degree of purity was calculated only for estradiol monovalerate: 99.72 ± 0.11 mol %. The fusion enthalpy (29.45±0.47 kJ mol^–1) and entropy for this compound were evaluated by differential scanning calorimetry. It was also possible to detect the polymorphism and the pseudopolymorphism of (a) and (b) after recrystallization from several solvents.

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Zusammenfassung Die thermische Stabilität, die Zersetzungskinetik sowie die Schmeiztemperaturen und -intervalle von Estradiol-Monovalerianat (a) und Estriol (b) wurden thermoanalytisch ermittelt. Nur der Reinheitsgrad von (a) wurde berechnet (99,72 ± 0,11 mol %). Die Schmelzenthalpie (29,45±0,47 kJ · mol^–1) und Schmelzentropie dieser Verbindung wurden mittels DSC bestimmt. Nach Rekristallisation in verschiedenen Lösungsmitteln konnten Polymorphie und Pseudopolymorphie für (a) und (b) nachgewiesen werden.

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, . 99,72±0,11 %. (29,45±0,47 · ^–1) . , .

     

Synthesis of 2β, 3β, 14α-trihydroxy-Δ4,7-6-ketosteroids and their derivatives

A scheme using -sitosterol as an example for synthesizing 2, 3, 14-trihydroxy-^4,7-6-ketosteroids and their derivatives from 3-hydroxy-⁵-steroids was developed.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141, Belarus, Minsk, ul, akad. Kuprevicha, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 244–248, May–June, 2000.     

Effect of the network structure on the flammability ofcis-1,4-polyisoprene vulcanizates

The combustibilities ofcis-1,4-polyisoprene and its peroxide and sulphur vulcanizates have been investigated by means of the oxygen index method. The temperature distribution in the sample and the molecular weight of the liquid products formed as a result of elastomer destruction in the combustion zone have been measured. It has been found that the combustibility ofcis- 1,4-polyisoprene diminishes as its cross-link density increases. This effect is much stronger for sulphur than for peroxide vulcanizates. The investigations lead to the conclusion that a mechanism of network degradation and volatile sulphur compounds penetrating to the flame are responsible for this difference.

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Zusammenfassung Die Brennbarkeit des unvernetztencis-1,4-Polyisoprens und seiner Peroxid- und Schwefelvulkanisate wurde mit der Sauerstoffindexmethode untersucht. Messungen der Temperaturverteilung im Prüfling wurden ebenfalls ausgeführt und das Molekulargewicht der infolge der Zersetzung der Elastomere in der Verbrennungszone entstehenden flüssigen Produkte mit der Methode der dynamischen Osmometrie bestimmt. Es wurde festgestellt, daß die Brennbarkeit des cis-1,4-Polyisoprens mit zunehmender Vernetzungsdichte abnimmt, und zwar viel ausgeprägter im Falle der Schwefel- als im Falle der Peroxidvulkanisate. Es wurde gefolgert, daß flüchtige, in die Flamme gelangende Schwefelverbindungen als Verbrennungsinhibitoren wirken.

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-1,4- . , . , -1,4- . . , .

     

Triterpene glycosides ofFatsia japonica. I. Isolation and structure of glycosides fromFatsia japonica seeds

The known triterpene glycosides hederagenin 3-O--L-arabinopyranoside, hederagenin 3-O-\-D-glucopyranoside, oleanolic acid 3-O--sophoroside, hederagenin 3-O--sophoroside, and their 28-O--gentiobiosyl esters, respectively, in addition to the new triterpene glycoside 3-O--sophorosyl-28-O--L-rhamnopyranosyl-(14)-O--gentiobiosyl hederagenin are isolated fromFatsia japonica (Araliaceae) seeds. The structures of these glycosides are established using chemical and spectral methods.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 131–133, March–April, 2000.     

Ab initio studies of the low-lying π-states of borazine

Self-consistent-field and configuration-interaction studies were performed on borazine, using a double-zeta basis set augmented by six diffuse -functions. Low-lying singlet and triplet states of the A ₁ , A ₂ and E species were calculated, corresponding to ^* excited valence and Rydberg states. A selection out of singly and doubly excited configurations relative to a set of reference configurations was made for each species. Calculated vertical excitation energies (in eV) are 7.12 for ¹ A ₂(V), 8.45 for ¹ E (3p-R), 8.57 for ¹ A ₁(V), 8.9 for ¹ E(V-R), 9.55 for ¹ E(3d-R), 6.98 for ³ A ₁(_V), 7.27 for ³ E(V), 7.82 for ³ A ₂(V), 8.30 for ³ E(3p-R), and 9.5 for ³ E(3d-R), where V and R refer to valence or Rydberg character. The results are compared with experimental excitation energies, previous ab initio studies of borazine, and with recent ab initio studies of benzene.Dedicated to Professor Dr. H. Hartmann on the occasion of his 65th birthday.     

Synthesis of new pyridazino[4′,3′:4,5]-thieno[3,2-d]-1,2,3-triazine and pyrimido[4′,5′:4,5]thieno[2,3-c]pyridazine derivatives

Summary 8,9-Diphenylpyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)-one (2), 3-substituted 8,9-diphenylpyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)-ones (3a–c), 3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin-8(7H)-one (4), 8-chloro-3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazine (5), 8-substituted 3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazines (6a–h) and 7-substituted 3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin-8(7H)-ones(7a–c) were synthesized from 5-amino-3,4-diphenylthieno[2,3-c]pyridazine-6-carboxamide (1).

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Synthese neuer Pyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-und Pyrimido[4,5:4,5]thieno[2,3-c]pyridazin-Derivate

Zusammenfassung Folgende Verbindungen wurden ausgehend von 5-Amino-3,4-diphenylthieno[2,3-c]pyridazin-6-carboxamid (1) synthetisiert: 8,9-Diphenylpyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)-on (2), 3-substituierte 8,9-Diphenylpyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)-one (3a–c), 3,4-Diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin-8[7H]-on (4), 8-Chlor-3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin (5), 8-substituierte 3,4-Diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazine (6a–h) und 7-substituierte 3,4-Diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin-8(7H)-one (7a–c).

     

Enhanced dissolution and oral bioavailability of α-tocopheryl esters by dimethyl-β-cyclodextrin complexation

Inclusion complexation of heptakis (2,6-di-O-methyl)--cyclodextrin (DM--CyD) with -tocopheryl acetate and -tocopheryl nicotinate in aqueous solution was studied by the solubility method. The aqueous solubilities of the esters were about 10⁵ times increased by DM--CyD complexation. The phase-solubility diagram of the tocopheryl ester-DM--CyD systems showed a typicalA _p type, and the stability constants (K) of high-order complexes were estimated by analyzing the upward curvature of the diagrams. The solid complex of -tocopheryl nicotinate with DM--CyD in a molar ratio of 12 was prepared by the kneading method. The dissolution rate of the solid complex was much greater than that of the drug itself, and the rapidly dissolving form of -tocopheryl nicotinate, as an example, showed a markedly increased bioavailability (about 70-fold) after oral administration to fasted dogs.     

A mathematical model of simultaneous absorption of two catalytically reacting gases

A mathematical model is suggested for the simultaneous absorption of two gases entering into a catalytic reaction in a plug-flow reactor (PFR). The effect of its parameters on the reaction process is analyzed.

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Thermal decomposition of heavy lanthanide 3-hydroxybenzoates in air and nitrogen atmospheres

The conditions of thermal decomposition of heavy lathanide complexes with 3-hydroxybenzoic acid in air and nitrogen atmospheres have been studied. On heating, the complexes of Gd, Dy, Ho, Yb and Lu decompose in three stages. First, the hydrated complexes lose crystallization water and the anhydrous salts heated in air are then transformed to Ln₂O₃, or in a nitrogen atmosphere to Ln₂O₃ and C. Complexes of Tb(III), Ho and Er are dehydrated in two stages during heating, and the anhydrous complexes are converted in air to Ln₂O₃ and Tb₄O₇, and in a nitrogen atmosphere to a mixture of oxides and C. The carbon content in the decomposition product ranges between 9.7% for Gd and 19.6% for Ho.The dehydration of the complexes is accompanied by endothermic effects. The decomposition of 3-hydroxybenzoates is exothermic in air and endothermic in nitrogen.

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Zusammenfassung Die Bedingungen der thermischen Zersetzung von Komplexen der schweren Lanthanide mit 3-Hydroxybensoesäure in Luft und Stickstoffatmosphäre wurden untersucht. Beim Erhitzen zersetzen sich die Komplexe von Gd, Dy, Ho, Yb und Li in drei Schritten. Zuerst verlieren die hydratisierten Komplexe Kristallwasser, die wasserfreien Salze ergeben dann in Luft Ln₂O₃ und in Stickstoffatmosphäre Ln₂O₃ und C als festen Rückstand. Komplexe von Tb(III), Ho und Er werden während des Erhitzens in zwei Stufen dehydratisiert und ergeben bei höheren Temperaturen in Luft Ln₂O₃ bzw. Tb₄O₇ und in Stickstoffatmosphäre eine Mischung der Oxide mit Kohlenstoff als festen Rückstand. Der Kohlenstoffgehalt des Zersetzungsproduktes liegt zwischen 9.7% für Gd und 19.6% für Ho. Die Dehydratisierung der Komplexe geht mit endothermen Effekten einher. Die Zersetzung von 3-Hydroxybenzoaten ist exotherm in Luft und endotherm in Stickstoffatmosphäre.

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3- . , , , , . , , — . , , — . , 9.7 19.6%. . 3- , — .

     

The electronic structure of molecules by a many-body approach

The vertical valence ionization potentials of cyclopropane, ethylene oxide and ethylene imine are calculated by a many-body Green's function method. For C₃H₆ the ordering of the ionization potentials is 2e(), 1e(), 2a₁(), 1a₂(), 1e(). The assignment of the 2a₁ and the 1a₂ ionization potentials which has been controversial is thus clarified. The ordering is in agreement with the result obtained via Koopmans' theorem. For ethylene oxide and ethylene imine Koopmans' theorem fails in predicting the correct order of ionic states. For C₂H₄O the ordering of the ionization potentials is 2b ₁(), 4a ₁, 1a ₂(), 2b ₂,3a ₁, 1b ₁(), 1b ₂, 2a ₁ and for C₂H₅N 6a, 5a, 3a, 2a, 4a, 3a, 1a, 2a. The agreement of the computed ionization potentials with the experimental values is very satisfactory.     

Beurteilung der thermischen Stabilität von Koksrohstoffen durch thermische Analyse

Zusammenfassung Bei der Untersuchung von Koksrohstoffen konnte ein enger Zusammenhang zwischen ihrer thermischen Stabilität beim Aufheizen auf Verkokungstemperatur und den Daten der thermischen Analyse nachgewiesen werden. Die dabei ermittelten Koksrückstände korrelieren mit der Koksausbeute bei druckloser Verkokung.

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Close connections were found between the thermal stabilities of coke raw materials during heating up to the coking temperature and their thermal analysis data. The obtained coking residues were in correlation with the coke yield of non-pressurized coking.

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Résumé On a trouvé un rapport étroit entre la stabilité thermique des matières premières du coke, lors de leur chauffage jusqu'à la température de cokéfaction, et les données de leurs analyses thermiques. Les résidus de cokéfaction obtenus sont en corrélation avec le rendement en coke dans le procédé de cokéfaction sans pression.

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Novel Synthesis of 22,25-Dideoxyecdysone and Its 5α-Isomer

22,25-Dideoxyecdysone (1) and 5-22,25-dideoxyecdysone (1a) were prepared from cholesterol via a new scheme using the key intermediates 3-chloro-5-bromo-6-ketone 3, 3-chloro-7-bromo-6-ketone 4, and 2,7-dien-6-one 7.     

Die Acetalgruppe, 1. Mitt. Acetale von Halogenmethyl-arylcarbinolen

Several halomethyl-arylcarbinols were prepared, and the influence of substituents on enantiomer selectivity in the acetalisation reaction with [2S-(2,3a,4,7,7a)]-octahydro-7,8,8-trimethyl-4,7-methanobenzofuran-2-ol was examined.

Unserem sehr verehrten Lehrer, Herrn Prof. Dr.Otto Hromatka, mit den besten Wünschen zum 80. Geburtstag gewidmet.