Recyclization of the pyridine ring under the influence of nucleophiles

Alkyl- and dialkylanilines are formed by the action of primary and secondary amines on nitropyridinium salts. An alkylamino or dialkylamino group is included in the final product in the step involving the open form. Aqueous methylamine may lead to opening of the ring of nonquaternized nitropyridines with subsequent formation of the benzene ring of alkylanilines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 98–102, January, 1979.     

Action of nucleophilic agents on the pyrimidine ring

It is shown that 2-alkylpyrimidine methiodides in which the alkyl group is activated by electron-acceptor substituents undergo recyclization to the corresponding 2-methylaminopyridines in an alcohol solution of methylamine. Similar recyclization also takes place without quaternization of the pyrimidine ring when there is a strong electron-acceptor substituent (a nitro group) in the ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1400–1405, October, 1978.     

The action of acetic anhydride on N-methyltryptophans

Summary A new furocoumarin of composition C₂₁H₂₂O₇ has been isolated from the fruit ofLibanotis transcaucasica Schischk. It has been established that libanotin is a derivative of 8-isopropyloxy-8,9-dihydroangelicin. The side groups of libanotin — acetic and 2-methyl-cis-crotonic acids — are attached to the main part of the molecule by ester bonds.Khimiya Prirodnykh Soedinenii, Vol. 1, No. 3, pp. 215–220, 1965     

Mass-spectrometric behavior of isomeric nitro- and nitroaminoindolizines and indoles

Peaks of [M — NO]⁺ and [M — NO₂]⁺ ions are characteristic for the mass spectra of nitroindolizines, whereas peaks of ions of the indole type, viz., [M — HCN]⁺ and [M- H,- HCN]⁺ (for alkylindoles), are not characteristic. In the mass spectra of nitroindoles the latter ions give more intense peaks, while the loss of a nitro group or its rearrangement is a considerably less significant process. When a dialkylamino group is introduced in the nitroindolizine molecule, the primary processes in the fragmentation of such compounds are due to fragmentation of the alkylamino group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 765–768, June, 1982.     

Nitropyridines: III. Synthesis of meta-terphenyls by recyclization of nitropyridinium salts

A two-component Hantzsch synthesis was applied to preparation of nitropyridines and their quaternary salts from various enamines and chalcones based on nitroacetophenone. The recyclization of nitropyridinium quaternary salts under the treatment with an aqueous-alcoholic alkali led to preparation of 5′-methylamino-2′-nitro-m-terphenyl derivatives.     

Chemistry of indole

,-Unsaturated ketones form pyrimido[1,2-a]indoles with 2-aminoindole, while 1-alkyl-2-aminoindoles under these conditions are converted to the corresponding -carbolines. The structures of the compounds obtained were confirmed by alternative synthesis.See [1] for communication XIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 61–64, January, 1971.     

Chemistry of indole

Condensation of 1-alkyl-2-aminoindoles with malonic ester gives -carbonyl derivatives which, on the basis of the their UV, IR, and NMR spectra, and their chemical properties, are assigned the 2-oxo-4-hydroxy--carboline structure.For Part XVIII, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1207–1211, September, 1970.     

Condensation of 2- tosylaminoindole with aromatic aldehydes

The condensation of 2-tosylaminoindole and 1-methyl-2-tosylaminoindoline with aromatic aldehydes gives primarily trans-3-arylidene derivatives, which exist in two tautomeric forms in solution.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 343–347, March, 1976.     

The Mechanism of Isomerization Recyclization of Diacetyl Derivatives of Pyridinium Salts

A mechanism has been considered for the recyclization of pyridinium salts using their diacetyl derivatives as an example. The enthalpies of formation of the intermediates were estimated by the molecular mechanics method (MMX88). The nature of the rate-determining step of the reaction is discussed.