Reduction of Alkyl-2-amino-5,6-dialkyl-3-cyanopyridine-4-carboxylates

Reduction of alkyl-2-amino-5,6-dialkyl-3-cyanopyridine-4-carboxylates with sodium borohydride in protic solvents gave rise to 4-amino-3-imino-6,7-dialkyl-1,3-dihydrofuro[3,4-c]pyridines that at hydrolysis in acid medium afforded the corresponding lactones.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 288–291.Original Russian Text Copyright © 2005 by Vasil’ev, Lyshchikov, Nasakin, Kayukov, Tafeenko.     

Structure of 6-β-[(hexahydro-1H-azepin-1-yl)methyleneamino]penicillanic acid sulfoxide

The oxidation of 6--[(hexahydro-1H-azepin-1-yl)methyleneamino]penicillanic acid with potassium periodate or m-chloroperbenzoic acid leads to the corresponding sulfoxide. Its structure was proved by alternative synthesis by splitting out the N-phenylacetyl group from the benzylpenicillin sulfoxide and condensation of the 6-aminopenicillanic acid sulfoxide with N-formylhexamethyleneimine dibutylacetal.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 649–651, May, 1982.     

Pyridylethylation of some heterocyclic thioamides and potential mercaptans

2-Pyridylethylation of benzazothiones-2 which are potential mercapto compounds (benzothiazolethione-2, benzoxazolethione-2, 1-methylbenzoimidazolethione-2, benzoimidazolethione-2, 5, 6-dimethylbenzoimidazolethione-2), is described, as well as preparation of 5, 6-dimethylbenzoimidazolethione-2 by direct oxidation of 5, 6-dimethylbenzoimidazole.     

Triterpene glycosides ofSapindus mukorossi

Conclusions The structure of two triterpone glycosides fromSapindus mukorossi Gaertn. has been established. It has been shown that sapindoside A is hederagenin 3-O--L-arabinosyl-(2 1)--L-rhamnopyranoside and sapindoside B is the 3-O--L-arabopyranosyl-(2 1)-O--L-rhamnopyranosyl-(3 1)--D-xylopyranoside.     

Influence of mobility of medium on dynamics of metallotropy in tin-containing 2-R-oxyphenoxyls

The rate of intramolecular migration of the triphenylstannyl group in 3,6-ditert-butyl-2(triphenylstannyl) oxyphenoxyl decreases with increasing viscosity of the medium. A linear relationship _ex=·_c is observed between the characteristic time of stannotropy _ex and the correlation time for reorientational motions of the radical _c within a range of temperature variation no greater than 30°C. The parameter depends on the medium; this is explained by the possibility of complexation of the radical with the solvent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 781–786, April, 1990.     

Reduction of 2,3,4-substituted quinolines with sodium borohydride

1,2-Dihydroquinolines were obtained by the reduction of 3-substituted 2-methyl-4-phenylquinolines with sodium borohydride in aliphatic carboxylic acids; N-alkyl derivatives are also formed. The corresponding 1,4-dihydroquinoline was obtained in the reaction of 2-methyl-3-nitroquinolinium perchlorate with sodium borohydride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1680–1686, December, 1991.     

Heterogeneous-catalytic fischer reaction

The catalytic synthesis of 7-azaindole and its 2-methyl derivative has been accomplished for the first time by cyclization of acetaldehyde and acetone 2-pyridylhydrazones in the presence of -Al₂O₃ and fluorinated aluminum oxide. The temperature dependence of the yields of reaction products — azaindoles and 2-aminopyridine — was studied. The cyclization of acetaldehyde 2-pyridylhydrazone proceeds under more severe conditions. The maximum yield of 7-azaindole is 15% at 450° on fluorinated aluminum oxide. The yield of 2-methyl-7-azaindole reaches 50% at 315°. Fluorinated aluminum oxide displays higher catalytic activity.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 656–658, May, 1972.     

EPR study of the mechanism of interaction of NO and NO2 molecules with zeolite surfaces

The adsorption of the paramagnetic molecules of NO and NO₂ by zeolites in the alkali and alkaline earth cationic forms has been studied by EPR and reflectance spectroscopic methods. The change in the EPR spectra of adsorbed nitric oxide with increase in the degree of covering of the surface of the alkali cationic form of the zeolites, and also the nature of the change in the spectra when oxygen is adsorbed on zeolites on which NO has previously been adsorbed, indicate the existence of two types of adsorption center. At low degrees of covering of the surface, on the order of 10¹⁸ g^–1, as can be judged from the EPR spectra, the adsorbed NO molecule is strongly polarized and the unpaired electron is almost completely localized on the oxygen atom. At high degrees of covering, for an appreciable proportion of the NO molecules, the bond with the surface is weaker. In this case, the EPR spectra show a hyperfine structure (HFS) with a constant which changes with change in the cation in the order Li⁺ Na⁺ K⁺. The replacement of the singly charged Na⁺ by the doubly charged Ca²⁺ produces a marked change in the adsorption properties of the zeolite. The adsorption of NO on CaA leads not only to polarization of the adsorbed molecule but also to transfer of the electron from the nitrogen atom to the atoms of the adsorbent; this is recorded in the EPR spectrum in the form of an F-center. On further adsorption, the NO molecules are adsorbed both on the nitrogen atom and on the oxygen atom of the first molecule; thus, NO₂ and N₂O are formed.