Dimerization of 1-vinyl-4,5,6,7-tetrahydroindole in the presence of acids

In the presence of Bronsted and Lewis acids, I-vinyl-4,5,6,7-tetrahydroindole is transformed into its dimes, 1-vinyl-2-[1-(4,5,6,7-tetrahydroindolyl)ethyl]-4,5,6,7-tetrahydroindole, and polymers containing units of the dimer and segments of oxidized tetrahydroindole cycles.Translated fromIzvestiva Akademii Nauk. Seriya Khindcheskaya, No. 2, pp. 423–425, February, 1996.     

Synthesis of benzazoles, 1,3,4-oxadiazoles,and 1,3,4-thiadiazoles containingβ-alkylthioethyl radicals

By the condensation of hydrochlorides of iminoesters of-alkylthiopropionic acids with o phenylenediamine, o-aminophenols, hydrazides of acids, and thiosemicarbazide, we have synthesized 2-substituted benzimidazoles and benzoxazoles, 2, 5-disubstituted 1, 3, 4-oxadiazoles, and 2-amino-5-substituted 1, 3, 4-thiadiazoles containing-alkylthiioethyl fragments.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 115–118, January, 1994.     

Gas Chromatographic Determination of Traces of O-Isobutyl S-2-(N,N-Diethylamino)ethyl Methyl Phosphonothioate (VX-Like Compound) in Working Area and Community Air

A gas-chromatographic procedure is proposed for the determination of O-isobutyl S-2-(N,N-diethylamino)ethyl methyl phosphonothioate (mixed ester) at the maximum permissible level for the working area air (5 × 10^–6 mg/m³) and at the safe reference level of impact for the community air (5 × 10^–8 mg/m³). The procedure is based on trapping the mixed ester from air by a chemisorbent. Next, the analyte is extracted by hexane; transformed to O-methyl-O-isobutyl methyl phosphonate by silver nitrate in methanol; and, in the case of the working area air, the methanol solution of the derivative is chromatographed. In the determination of the mixed ester in the community air, a solution of O-methyl-O-isobutyl methyl phosphonate (dialkyl methyl phosphonate) in methanol is passed through a column with an adsorbent and transferred to the chromatographic system with a thermal desorption system. The relative error of the determination of the mixed ester in the working area and community air is no more than 28 and 40 rel. %, respectively.     

Reactions of cyclammonium cations

The polarographic reduction of pyridinium cations with various substituents both in the nucleus and at the heteroatom has been investigated. The reduction mechanism is determined y the substituents in the pyridine nucleus. Substituents attached to the nitrogen atom and to carbon atoms of the ring affect the electrophilicity of pyridinium cations differently.For Communication XXI, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1067–1072, August, 1973.     

Preparation of chloromethyl derivatives of dibenzo-18-crown-6 and syntheses based on them

The reaction of chloromethylated dibenzo-18-crown-6 and some monosubstituted derivatives (4-acetyl-, 4-propionyl-, and 4-tert-butyldibenzo-18-crown-6) was studied. Modification of the chloromethyl group resulted in the synthesis of various dibenzo-18-crown-6 derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 470–474, April, 1989.     

Reactivity of Benzophenone O-Vinyloxime

Benzophenone O-vinyloxime readily takes up bromine and hydrogen chloride to give benzophenone O-(1,2-dibromoethyl)oxime and benzophenone O-(1-chloroethyl)oxime, respectively. Its reactions with methanol, trifluoroacetic acid, and acetic acid lead to formation of the corresponding O-(1-methoxyethyl), O-(1-trifluoroacetoxyethyl), and O-(1-acetoxyethyl) derivatives. Slow heating of the title compound induces its decomposition with formation of benzophenone as the major product; fast heating leads to a complex mixture of products containing benzophenone, benzophenone imine, and acetaldehyde.     

Radical Scavenging Activity of Antioxidants by Cyclic Voltammetry

This work investigates the reactivity of individual antioxidants with the free radicals generated by 2,2′-azobis(isobutironitrile) (AIBN). The consumption of antioxidants was followed by cyclic voltammetry. The fitting of such decay with a kinetic model yielded the rate constant of radical formation and the rate constant of radical inhibition exerted by each antioxidant. The antioxidant efficiency was defined as the ratio between and . The following ranking of antioxidants was obtained: α-tocopherol≫catechin≫retinyl acetate≫hydroxytyrosol≫oleuropein≫caffeic acid. Overall, the approach shows the utility of cyclic voltammetry to investigate the kinetic rates at which antioxidants react with radicals.     

Polynuclear tetrazole-containing amino acid analogs

New analogs of (D,L)-phenylalanine containing tetrazole rings were synthesized. The acidity constants of (D, L)-phenylalanine and (D,L)-tryptophane derivatives containing a tetrazole ring with no substituent on N¹ (pK _a = 3.0–3.1) and of the corresponding carboxylic acids (pK _a = 2.9–3.3) in aqueous methanol were determined by potentiometric titration.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1576–1579.Original Russian Text Copyright © 2004 by Morozova, Esikov, Zubarev, Malin, Ostrovskii.     

Synthesis and modification of 1-vinylpyrrole-2-carbaldehyde polymers

1-Vinylpyrrole-2-carbaldehydes, viz., 5-phenyl-1-vinylpyrrole-2-carbaldehyde, 5-(2-thienyl)-1-vinylpyrrole-2-carbaldehyde, 1-vinyl-4,5,6,7-tetrahydroindole-2-carbaldehyde, and 1-vinyl-4,5-dihydrobenz[g]indole-2-carbaldehyde, are polymerized in the presence of 2,2-azobisisobutyronitrile to form soluble paramagnetic oligomers. A possibility of oligomer modification through the aldehyde moiety with amines and thiols was shown. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2134–2137, November, 2007.