The chemistry of indole

The opening of the pyrazolidine ring at the nitrogen-nitrogen bond in 1-arylpyrazolidine under the influence of acidic agents which leads to the formation of N-(3-aminoalkyl)indoles is described. The method enables one to obtain indoles with branched aminoalkyl radicals.For part XIII see [1].     

Bromination of 3-acyl-2-aminoindoles

Unlike 3-acylindoles, 3-acyl-2-aminoindoles display high selectivity on being electrophilically attacked in the benzene ring, and are substituted at the 6-position. At the same time, an unco-subsitution of the acyl group takes place (to the greatest extent — the formyl group). Direct bromination of 3-acyl- and 3-cyano-2-aminoindoles provides the 6-bromo- and 6,4-dibromo-2-aminoindoles and their derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 486–490, April, 1990.     

Reactions of Hydroxyazolidines with π-Donor Heterocycles. 3. Reaction of 1-Acetyl-5-hydroxypyrazolidines with Oxindoles

The reaction of oxindoles with 5-hydroxypyrazolidines on the surface of potassium fluoride-modified alumina leads to 3-(5-pyrazolidinyl)oxindoles. The structure of these products was studied.     

Reactions of hydrazine derivatives

Conditions were worked out for the synthesis of a number of 1-arylpyrazolidines with alkyl groups in the 4 and 5 positions of the five-membered ring by reduction of the corresponding 3- or 5-pyrazolidones with lithium aluminum hydride.See [1, 2] for communications XLVI And XLVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 118–121, January, 1971.     

Synthesis of new functional derivatives of pyrazolidine from 1-acetyl-3-methyl-5-nitromethyl-2-phenylpyrazolidine

3-Nitromethylpyrazolidine reacts with derivatives of unsaturated acids and reducing agents with the formation of polyfunctional compounds of the pyrazolidine nucleus. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1365–1369, September, 2006.     

Preparation and properties of azinium salts of the 2-pyrazoline series

Azinium salts containing pyrazoline fragments have been obtained by the reaction of 2-pyrazolines with aromatic and heteroaromatic aldehydes, acetylacetone, and acetoacetic ester in the presence of H₂SnCl₅ and HBF₄. Reactions of nucleophilic addition to the multiple bonds and also some cycloaddition reactions among the arylidene derivative have been studied. From the azinium salts of a series of -dicarbonyl compounds have been obtained previously unknown enamino carbonyl compounds of the 2-pyrazoline series.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 101–105, January, 1984.     

Indefinite binary quadratic forms with large class numbers

This article describes all discriminants D for which the length of the period of the expansion of D in a continued fraction is equal to 2, 3, 4, or 6. It is proved that such discriminants are small. Similar propositions are proved for prime discriminants D=.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova Akademii Nauk SSSR, Vol. 185, pp. 13–21, 1990.     

Synthesis of high-purity lower silicon alcoholates for new technology

Purification of a number of silicon derivatives (chloride, lower alcoholates) formed in processing of high-purity silicon for electronic and electrical industries was considered. It was found that high-purity substances suitable for use in electronics and optics can be produced from industrial wastes.     

Solid Echo in Three-Spin Groups with Arbitrary Constants of Dipole–Dipole Interaction

Applied Magnetic Resonance - The suggested approach allowed us to derive analytical expressions for modeling the shape of solid-echo signal and its time evolution for a system of three-spin groups...     

Catalytic system based on nickel(II) acetate and hypophosphorous acid for the selective hydrodeoxygenation of guaiacol

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