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.     

Electrophilic addition of phenols to 1-vinyl-4,5,6,7-tetrahydroindole

Both uncatalyzed and acid-catalyzed (CH₃COOH) addition of phenols to 1-vinyl-4,5,6,7-tetrahydroindole gave 1-(1-aroxyethyl)-4,5,6,7-tetrahydroindoles. With increasing acidity of the phenol and in the presence of CF₃COOH the yield of adducts was lowered because of the oligomerization of 1-vinyl-4,5,6,7-tetrahydroindole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 604–606, May, 1989.     

Electrical conductivity of copolymers of 1-vinyl-1,2,4-triazole with N-vinyl-4,5,6,7-tetrahydroindole

New copolymers of 1-vinyl-1,2,4-triazole with N-vinyl-4,5,6,7-tetrahydroindole of different compositions were synthesized. The processes of doping them with diiodine and electrophysical properties were studied. An increase in the electrical conductivity of the diiodinedoped copolymers by seven orders of magnitude due to the formation of charge-transfer complexes was observed.     

Copolymerization of vinyl chloride with 1-vinyl-4,5,6,7-tetrahydroindole and 2-methyl-5-vinylpyridine

The radical copolymerization of vinyl chloride with 2-methyl-5-vinylpyridine and 1-vinyl-4,5,6,7-tetrahydroindole is accompanied by dehydrochlorination. In the vinyl chloride-2-methyl-5-vinylpyridine system, the evolved hydrogen chloride interacts with a pyridine hydrogen atom to give charged units of a heterocycle. In the vinyl chloride-1-vinyl-4,5,6,7-tetrahydroindole system, the hydrogen chloride being formed initiates the cationic dimerization of a nitrogen-containing monomer. The synthesized copolymers based on vinyl chloride surpass the commercial poly(vinyl chloride) in terms of thermal stability and solubility in organic solvents.     

1-Vinyl-1,2,4-triazole in copolymerization reaction with 1-vinyl-4,5,6,7-tetrahydroindole: synthesis and properties of copolymers

A radical copolymerization of 1-vinyl-1,2,4-triazole (VTA) with 1-vinyl-4,5,6,7-tetrahy-droindole (VTHI) was studied. New thermally stable functional copolymers of different composition, well soluble in organic solvents were synthesized. It was found that VTA has higher reactivity as compared to VTHI. A new soluble polymeric nanocomposite with metallic silver nanoparticles encapsulated into the matrix of synthesized copolymer was obtained.     

Copolymerization of N-Vinyl-4,5,6,7-tetrahydroindole with Acrylamide

Radical copolymerization of N-vinyl-4,5,6,7-tetrahydroindole with acrylamide in dimethylformamide was studied, and the relative activity constants of the monomers were determined.     

A preparative synthesis of indole by dehydrogenation of 4,5,6,7-tetrahydroindole over catalysts with a low palladium content

Catalysts containing 0.15–0.5 % of Pd are highly active and selective in the dehydrogenation of 4,5,6,7-tetrahydroindole to indole when γ-Al₂O₃ or Sibunite are used as supports. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1832–1833, October, 1993.     

Pyrroles from ketoximes and acetylene 8. Synthesis of 4,5,6,7-tetrahydroindole and its 1-vinyl derivative

4,5,6,7-Tetrahydroindole or 1-vinyl-4,5,6,7-tetrahydroindole was obtained in 81 and 93% yields, respectively, by reaction of cyclohexanone oxime with acetylene at 90–140C in the presence of alkali metal hydroxides or alkoxides in dimethyl sulfoxide (DMSO) or mixtures of DMSO with low-polarity or nonpolar solvents. The reaction is effective both in an autoclave (initial pressure 8–16 gage atm) and at atmospheric pressure.See [1] for communication 7.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 197–199, February, 1979.     

Free-radical cooligomerization of N-vinyl-4,5,6,7-tetrahydroindole with butyl vinyl ether

Oligo(N-vinyl-4,5,6,7-tetrahydroindole-co-butyl vinyl ethers) have been synthesized through free-radical cooligomerization with a yield of 84%. The copolymers are readily soluble in organic solvents (benzene, 1,4-dioxane, chloroform, and tetrahydrofuran), stable up to 380–400°C, and paramagnetic. (The concentration of paramagnetic centers is 10¹⁴ spin/g.) In addition, the copolymers exhibit the properties of organic semiconductors. (After being doped with iodine, σ = 1.1 × 10^?7 S/cm.) The analysis of the ¹H and ¹³C NMR spectra has shown that the oligomerization reaction is complicated by intramolecular cyclization involving carbon atoms located at the 2-position of pyrrole rings.     

Copolymerization of 1-Vinyl-4,5,6,7-tetrahydroindole with Vinyl Chloride in the Presence of a Radical Initiator

Copolymerization of 1-vinyl-4,5,6,7-tetrahydroindole with vinyl chloride in the presence of azobis(isobutyronitrile) occurs as a two-step process. The copolymer is initially formed by the radical mechanism. Then, the eliminated hydrogen chloride initiates cationic oligomerization of 1-vinyl-4,5,6,7-tetrahydroindole, enriching the copolymer with units of this monomer.     

One-electron transfer in the vinylation of 4,5,6,7-tetrahydroindole with acetylenes in the system KOH-DMSO

It has been shown by EPR, using 2-methyl-2-nitrosopropane as a radical trap, that vinylation of 4,5,6,7-tetrahydroindole with phenylacetylene in the system KOH-DMSO involves the formation of the 4,5,6,7-tetrahydroindolyl radical by transfer of an electron from the 4,5,6,7-tetrahydroindole anion to the acetylene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 142–144, January, 1990.     

Synthesis and mass spectrometry of 4-oxo-4,5,6,7-tetrahydroindole and 4-oxo-4,5,6,7-tetrahydrobenzofuran derivatives

We describe in this communication the synthesis and mass spectrometry of some l-aryl-2-phenyl-4-oxo-4,5,6,7-tetrahydroindole (IIIb, IVab-VIIIab, VIIIb, IXb) and 2-phenyl-4-oxo-4,5,6,7-tetrahydrobenzofuran derivatives (IIab). The fragmentations of these compounds are characterized by selectivity and the absence of any primary fragmentations involving substituents of the aryl rings. It is suggested that positive charges of the molecular ions of compounds II? IX are localized in the region of the carbonyl group and the conjugated double bond of the heterocycle.     

Condensation of 2-amino-3-cyano-4,5,6,7-tetrahydroindole with Β-dicarbonyl compounds

Depending on conditions, the condensation of 2-amino-3-cyano-4,5,6,7-tetrahydroindole with -dicarbonyl compounds leads to 2-methyl-4-oxo- or 4-methyl-2-oxo-10-cyano-6,7,8,9-tetrahydropyrimido[1,2-a]indoles via the intermediate compounds: 2-(3-ethoxy-carbonyl-prop-2-en-2-yl amino) and 2-(1,3-dioxobutylamino)-3-cyano-4,5,6,7-tetrahydroindoles, respectively.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 833–838. June, 1989.     

Cross-coupling of 4,5,6,7-tetrahydroindole with functionalized haloacetylenes on active surfaces of metal oxides and salts

Screening was performed of metal oxides (MgO, CaO, ZnO, BaO, Al₂O₃, TiO₂, ZrO₂) and salts (CaCO₃, K₂CO₃, ZrSiO₄) as active surfaces for the reaction of ethynylation of 4,5,6,7-tetrahydroindole with ethyl bromopropynoate and bromobenzoylacetylene. It was established that Ca, Mg, Zn, and Ba oxides assist the ethynylation of 4,5,6,7-tetrahydroindole, and their activity in the reaction with ethyl bromopropynoate considerably exceeds that of aluminum oxide. The ethynylation is accompanied with the formation of intermediate E-2-(1-bromoethenyl)-4,5,6,7-tetrahydroindole and side 1,1-di(4,5,6,7-tetrahydroindol-2-yl)ethenes and 1,1-di(4,5,6,7-tetrahydroindol-2-yl)bromoethanes.