Thermal Behaviour of the Complexes of Zinc Amino Acids

The eight solid complexes of zinc with L--methionine or L--histidine were prepared. The thermal decomposition processes of these complexes were determined by means of TG-DTG. The results show that their decomposition processes can be divided into three steps except for the complex Zn(Met)₂ the decomposition of which is completed in one step. All the final products are ZnO.This revised version was published online in November 2005 with corrections to the Cover Date.     

Simple synthesis of benzo[f] pyrrolizidine and benzo[g]indolizidine with the use of products of the reductive allylation of indole and quinoline

Benzo[f]pyrrolizidine and benzo[g]indolizidine were synthesized by hydroboration-oxidation-intramolecular cyclization of the corresponding products of the reductive -allylation of indole (2) and quinoline (6) with allylboranes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No, 11, pp. 2807–2809, November, 1996,     

Separation and identification ofα, ω-diiodoperfluoroalkanes in gas chromatography

Summary The separation of ,-diiodoperfluoralkanes on a glass capillary column coated with OV-101 methylsilicone was investigated. Retention indices were determined at three temperatures (140, 150 and 160°C). The correlation between the retention indices and the boiling points of the investigated compounds was studied.     

Synthesis and biological activity of yuccagenin bisrhamnoside

The two hydroxyls of yuccagenin can be glycosylated by Koenigs-Knorr condensation with acetobromorhammose in dichloroethane in the presence of mercuric cyanide. The bisrhamnoside of yuccagenin markedly lowers the cholesterol and triglyceride content in blood serum of healthy animals and animals with experimental hyperlipidemia.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 242–243, May–June, 2000.     

Effects of α-tocopherol and its acetate on the hydrolytic activity of phospholipase D in egg yolk phosphatidylcholine bilayers

Effects of -tocopherol (Toc) and -tocopherol acetate (TocA) on the hydrolysis activity of phospholipase D (fromStreptomyces chromofuscus) were studied in small unilamellar vesicles (SUV) of egg yolk phosphatidylcholine (PC). Choline produced in the reaction was monitored by use of a choline oxidase — oxygen electrode. Addition of 18 mol% Toc into SUV (2 mM PC) brought about a twofold rate of choline production. On the other hand, the effect of 18 mol% TocA in SUV was very small. The apparent maximum velocity,V _max(app), increased by addition of Toc in SUV. The apparent Michaelis constant,K _m(app), was unchanged by addition of Toc and TocA in SUV. The Toc and TocA molecules did not have significant effects when PC was solubilized in the micelles of heptaethylene glycol dodecyl ether. The effects of Toc and TocA are, therefore, not due to specific ones on the enzyme itself, but rather upon the bilayer-organization of the substrate. Measurements of spreading pressure showed complete miscibility of PC and Toc, and limited mutual solubility of PC and TocA, suggesting stronger attractive interactions between Toc and PC than those between TocA and PC in the bilayers.     

Amino- und Hydroxylaminosubstituierte α-Azidozimtsäureester und α-Aminozimtsäureester durch kathodische Reduktion ungesättigter Nitroazidoester

Cathodic reduction of nitro-substituted azidocinnamic esters on mercury under aprotic and protic conditions was studied. Nitro and azido groups behave as independent entities so that selectively amino- resp. hydroxylamino--azido compounds are obtained, which could not be synthesised by conventional methods. Under aprotic conditions, with added acetic anhydride, medium yields of acylated 4-hydroxylamino- and 4-amino--cinnamic acid derivatives are isolated. Evidence of homogeneous electron transfer from nitroanion radicals to azido groups is given.

     

Asymmetric reduction of acetophenone and propiophenone by NaAl(IPTOLate)H2 combined with enantiomeric enrichment of the reaction product as an inclusion complex with IPTOL

An improved procedure was developed for asymmetric reduction of acetophenone and propiophenone by the chiral reagent NaAl(IPTOLate)H₂. This procedure is based on isolation of the chiral alcohol that formed as a crystalline host—guest complex with the IPTOL ligand. The enantiomeric enrichment of the product was as high as 97% ee. The ability of IPTOL and its analogs to form host—guest complexes with a number of ether-type solvents, 1-phenylethanol, and 1-phenylpropan-1-ol as well as thermal stabilities of IPTOL-containing complexes with these alcohols were studied.     

Thermolytic transformations of polyfluoroorganic compounds

Copyrolysis of 4-chlorotetrafluorobenzotrichloride with chlorodifluoromethane (as the source of difluorocarbene) gave 4-chlorodifluoromethyl--chlorohexafluorostyrene, 1,4-dichlorotetrafluorobenzene, and 4-(chlorodifluoromethyl)chlorotetrafluorobenzene along with 4-chloro--chlorohexafluorostyrene. Possible routes for the formation of these products have been offered.For Part 30, see Ref. 1.Translated fromIzevstiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2199–2202, December, 1994.     

Linear and cyclicN-acyl-α-arylglycines III. Synthesis and chemiluminescence studies of naphthol and phenanthrol amidoalkylation products

Summary The synthesis of new linear and cyclicN-acetyl--arylglycine derivatives (2–10) and of the desoxybenzoin amidoalkylation product13 is described. In addition, an investigation of the chemiluminescence observable upon base-induced oxidation with oxygen is reported.

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Lineare und CyclischeN-Acetyl--arylglycine, 3. Mitt. Synthese und Chemilumineszenz-Untersuchungen von Naphthol- und Phenanthrol-Amidoalkylierungsprodukten

Zusammenfassung Es wird über die Darstellung von linearen und cyclischenN-Acetyl--arylglycinderivaten (2–10) sowie jene des Desoxybenzoin-Amidoalkylierungsprodukts13 berichtet. Weiters wird die Chemilumineszenz, welche bei basisch induzierter Oxidation mit Sauerstoff zu beobachten ist, untersucht.

     

Certain Transformations of Anabasine and Nicotine

Electrocatalytic reduction of the alkaloids anabasine and nicotine was investigated. 1-,-Dipiperidyl and hexahydronicotine were prepared. The reactions of anabasine and the hydrogenated alkaloids with dicarboxylic acid anhydrides were studied.     

Study of modified silicas by inverse gas chromatography. Part I: Influence of chain length on grafting ratio

Summary Silica has been modified by an esterification reaction using either n-alcohols or - diols. The grafting ratios were evaluated by elemental analysis of carbon or by the weight loss of the grafted silica heated to 700°C. The grafting ratio can be easily fixed by changing the silica to reactant impregnation ratios. In the case of n-alcohols, the grafting ratios do not vary monotonously with the number of carbon atoms of the grafts and the density of the grafted layer is 25% higher for - diols than for n-alcohols. This observation needs further investigation.     

Elektrolyse substituierter Azidozimtsäure- und Azidoacrylsäureester

Several ring-substituted -azidocinnamic and -heterocyclic -azidoacrylic esters are subject to cathodic reduction under aprotic and protic conditions. Good to excellent yields of rather labile dehydroaminoacid derivatives resp. stableN,N-diacylated enaminoesters are selectively obtainable. The compounds are characterised by spectroscopic methods (¹H-NMR, IR, MS).

     

Polyimides from complexes of benzophenonetetracarboxylic acid diesters with diamines. 5. Mechanism of thermal cyclization of H-complexes

The results of a study, by thermal mass spectrometric analysis and NMR spectroscopy, of the polycondensation of H-complexes are presented from which it is possible to propose a mechanism for the reaction. It is shown that conversion of the H-complexes into polyimides takes place through the formation of intermediate zwitterions with an amino acid bond after initial separation of methanol, following which elimination of water commences in one stage to form an imide ring. The role of theortho position of the functional groups in the acid ester during the formation of the hydrogen bond is discussed.Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004 St. Petersburg. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2517–2524, November, 1992.     

Cyclodextrin-accelerated oxidation of iodide by oxygen in aqueous solutions containing HClO4

The oxidation of iodide to I ₃ ^– by oxygen dissolved in water containing HClO₄ has been found to be accelerated by -cyclodextrin (-CD). Among -, -, and -CDs, -CD is the most effective mediator for the oxidation reaction of iodide by oxygen. The oxidation rate of iodide is first order in the concentrations of -CD and HClO₄, whereas it is second order in the KI concentration.Part of this work was carried out at Department of Physics, Miyazaki Medical College, Miyazaki 889-16, Japan.     

Selective liquid-liquid extraction of xylene isomers and ethylbenzene through inclusion by branchedα-cyclodextrins

Branched-cyclodextrins (CDs) such as glucosyl--CD(G--CD) were found to be very effective reagents for selective liquid-liquid extraction of xylene isomers and ethylbenzene since their inclusion complexes did not precipitate and handling of solids was not necessary. Reaction temperatures higher than room temperature did not increase the yield. The inclusion complexation proceeded fast. The liquid-liquid extraction process was found to be energy-saving and not time-consuming.     

Synthesis of 1,3,5-triazabicyclo[3.1.0]hexanes containing the fragments of α-amino acids and their esters at the N(3) atom

With 3,3-pentamethylene-1,2H-diaziridine as an example, it was shown that 3,3-dialkyl-1,2H-diaziridines can undergo cyclocondensation with -amino acids and their esters to give the corresponding N(3)-substituted 1,3,5-triazabicyclo[3.1.0]hexanes, including pure enantiomers.     

Electronic structure of monosubstituted benzenes and X-ray emission spectroscopy

The electronic structure of the benzaldehyde molecule has been studied by X-ray emission spectroscopy. The gas-phase O-K- and C-K-spectra of this compound have been obtained. MNDO quantum-chemical calculations have been carried out. The structure of the MO's of benzaldehyde has been compared with those of benzene and formaldehyde molecules. The character of the p-p interaction of the phenyl and formyl fragments has been considered. The contribution of the latter to the highest occupied molecular orbitals of the-system has been shown to be small.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1033–1037, June, 1994.     

Tetracyclic triterpenes. Part 5. The synthesis of epimeric 9,11-epoxides in the tri-, hexa-, and octa-norlanostane series

Lanosterol was converted by degradation of the side chain followed by transformations within rings B and C into a series of 9,11-epoxy-7-oxo-4,4,14-trimethylsteroids.Part IV.Paryzek, Z., Wydra, R., Bull. Acad. Polon. Sci., Ser. sci. chim.26, 591 (1978).     

Dimethyl dichloromalonate as a new synthetic equivalent of methyl dichloroacetate in the Darzens condensation

Dimethyl dichloromalonate reacts with aldehydes in the presence of sodium methoxide to form-chloropyruvates,-chloroglycidates, or,-dichlorohydrins, depending on the nature of the aldehyde.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1544–1545, August, 1995.