Reactions of heterocyclic cations with N-containing nucleophiles. 13. Investigation of the reaction of 2,4,6-triarylpyrylium salts with hydrazines,semicarbazide, and thiosemicarbazide

The recyclization reactions of 2,4,6-triphenylpyrylium perchlorate with hydrazine and methyl-, phenyl-, benzoyl-, and benzalhydrazines in dimethylformamide (DMF), which proceed differently than in ethanol, were examined. 7-Oxo and 7-thioxo derivatives of 2,3a,5-triphenyl-3H-pyrazolo[1,5-c]pyrimidine were obtained by transformation of 2,4,6-triarylpyrylium salts with semicarbazide and thiosemicarbazide in DMF. The tautomeric forms of the products were established by mass spectrometry and chemical transformations.See [1] For Communication 12.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 695–701, May, 1983.     

Reactions of heterocyclic cations with nitrogen-containing nucleophiles. 12. Reaction of pyrylium salts with azomethines

The reaction of pyrylium salts with azomethines leads to the formation of styrylpyrylium, styrylpyridinium, and 4-arylbenzylaminopyrylium salts. The reaction of the latter with ammonia and amines gave pyridines and pyridinium salts with a tertiary amino group as a substituent.See [1] for Communication 11.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 465–468, April, 1982.     

Reactions of heterocyclic cations with N-containing nucleophiles. 17. Synthesis of pyrylium salts with three-ring azole substituents

2,6-Diphenylpyrylium perchlorate was hetarylated with imidazo- and pyrrolo-[1,2-a]benzimidazoles, and deeply colored 4-azolylpyrylium perchlorates were obtained.See [1] for communication 16.Communication 24 from the series Research on imidazo[1,2-a]benzimidazole derivatives. See [2] for communication 23.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 309–313, March, 1987.     

Ethynyl carbonium ions. 2. Reactions of 4-ethynylpyrylium perchlorates with alcohols and nitrogen-containing nucleophiles

Derivatives of -alkoxy- and -(phenylamino)styrylpyrylium salts, the hydrolysis of which leads to phenacylpyrylium salts and 4-benzoylmethylenepyrans, are formed in the reaction of 4-phenylethynylpyrylium salts with alcohols and aromatic amines. Ethynyl-substituted pyridines and pyridinium salts were synthesized by the action of ammonium acetate and methylamine, benzylamine, and butylamine. A -methylaminostyryl-1-methyl-substituted pyridinium salt is formed with excess methylamine.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 299–306, March, 1990.     

A C-13 study of the reaction of 2,4,6-triarylpyrylium cations with amines

The reaction of primary and secondary amines with 2,4,6-triarylpyryliums is shown by C-13 NMR to proceed by fast ring opening to a vinylogous amide; in the case of primary amines this closes slowly to a pyridinium salt. The reaction in DMSO gives the pyridinium salt quantitatively when 2 moles of amines are used, with less amine significant quantities of a diketone intermediate are produced which results in slower conversion.     

Reactions of heterocyclic cations with nitrogen-containing nucleophiles. 11. Reaction of 2,6-diphenylpyrylium perchlorate with primary amines,hydrazine, and hydroxylamine

The reaction of 2,6-diphenylpyrylium perchlorate with methylamine and various anilines in acetic acid leads to pyridinium salts; 3,4-bispyridinium perchlorates were obtained in dimethylformamide. The reaction of 2,6-diphenylpyrylium perchlorate with hydrazine and the sodium salt of hydroxylamine leads to 3-phenyl-5-phenacyl-2-pyrazoline and -2-isoxazoline.See [1] for Communication 10.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 461–464, April, 1982.     

Ring transformations of heterocyclic compounds. XV. N-(2-hydroxyphenyl) substituted 2-alkylamino-4,6-diarylbenzophenones by ring transformation of 2,4,6-triarylpyrylium salts with anhydrobases of benzoxazolium salts

The synthesis of hitherto unknown N-(2-hydroxyphenyl) substituted 2-alkylamino-4,6-diarylbenzophenones 3 from 2,4,6-triarylpyrylium salts 1 and 3-alkyl-2-methylbenzoxazolium salts 2 in the presence of triethylamine in ethanol by a 2,5-[C₄+C₂] pyrylium ring transformation is reported. Structure elucidation is performed by an X-ray crystal structure determination of the benzophenone 3a. Spectroscopic data of the transformation products and their mode of formation via anhydrobases of the salts 2 are discussed.     

Reactions of N-alkylazinium cations. 3. Quaternary pteridinium salts. Synthesis,structure, and reactions with simple nucleophiles

4-Morpholinopteridine reacts with triethyloxonium tetra-fluoroborate to give two types of isomeric quaternary salts, viz., 1-ethyl- and 8-ethyl-4-morpholinopteridinium tetrafluoroborates. The structures of the pteridinium cations were proved by the ¹H and ¹³C NMR spectra and also by chemical transformations in reactions with simple nucleophiles.See [1] for communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1257–1264, September, 1985.     

Reactions of heterocyclic cations with n-containing nucleophiles. 15. Reaction of 2,6-diphenylpyrylium perchlorate with semi- and thiosemicarbazides

The reaction of 2,6-diphenylpyrylium perchlorate with semi- and thiosemicarbazides in ethanol leads to 1-carbamoyl- and 1-thiocarbamoyl-3-phenyl-5-phenacyl-4,5-dihydropyrazoles, the cyclization of which yields 2,5-diphenyl-7-oxo(thio)-pyrazolo[1,5-c]pyrimidines. The tautomeric form of the latter is established by comparing their electronic absorption spectra with the spectra of the methyl derivatives.For Communication 14, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1635–1640, December, 1986.     

Reactions with heterocyclic diazonium salts. Synthesis of several new azolylhydrazones

Several new stable azolylhydrazones could be synthesized via coupling of diazotised cycliuc amidines with active methylene reagents. The obtained compounds were utilised for synthesis of several, otherwise not readily accessible fused azoles.     

Reactions of heterocyclic cations with N-containing nucleophiles. 16. Study of the interaction of 2,6-diphenylpyrylium perchlorate with diazoles

The direct interaction of 2,6-diphenylpyrylium perchlorate with pyrazoles and pyrazolones led to the synthesis of 4-azolylpyrylium salts, which readily cleave a molecule of perchloric acid in the case of the N-unsubstituted pyrazolones, being converted to pyranylidene derivatives.For Communication 15, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 182–187, February, 1987.     

Reactions of 1,2-bis(trifluoroacetyl)benzene with nucleophiles leading to heterocyclic compounds

The reaction of 1,2-bis(trifluoroacetyl)benzene (II) with ammonia, hydrazine, hydroxylamine and L-alanine has been investigated and the resulting heterocyclic compounds fully characterized on the basis of spectral data. The reaction of II with $\text{o}$-aminophenol and $\text{o}$-phenylenediamine led to the formation of tetracyclic compounds XI and XII respectively. The structure of compound XII has been further supported by single crystal X-ray crystallography. Our studies reveal the potential of the diketone II as a valuable synthon for the synthesis of a variety of heterocyclic systems with trifluoromethyl substituents.     

Cyclizations of N-alkylazinium cations with bifunctional nucleophiles. 18. Synthesis and structure of heterocyclic systems based on quinoxaline

N-Methylquinoxalinium iodide reacts with ethylenediamine, o-phenylenediamine, and o-aminophenol to give cyclization products of the type involving [2,3-b] annelation of the six-membered heteroring. Two molecules of the quinoxaline participate in the cyclization with 2-aminoethanol to give a complex polycyclic compound.See [1] for communication 17.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1116–1124, August, 1985.     

Studies on fluorine-containing heterocyclic compounds. 3. Reactions of 3,5-dinitro-2-chlorobenzotrifluoride and 3,5-dinitro-4-chlorobenzotrifluoride with sulfur and nitrogen-containing nucleophiles

The reactions of 3,5-dinitro-4-chlorobenzotrifluoride (la) and 3,5-dinitro-2-chlorobenzotrifluoride (lb) with sulfur- and nitrogen-containing nucleophiles furnished the substituted benzothiazo-N-oxide (3,5) and S-(5-nitro-2-trifluoromethylphenyl-1,4-dithioglycolic ethyl ester(4). Similarly, the reaction of ethyl aminoacetate with lb gave substituted imidazol-N-oxide(8) and tetraazacyclooctanol(9). The possible mechanisms for the formation of 9 were discussed.     

Synthesis of nitrogen-containing condensed heterocyclic compounds by catalytic dehydrocyclization of substituted pyridine bases (review)

Reactions involving the catalytic dehydrocyclization of synthetically accessible substituted pyridine bases, as a result of which condensed nitrogen-containing heterocyclic compounds containing three, four, and five rings are formed, are examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1011–1021, August, 1988.     

Ring transformations of heterocyclic compounds. X. A simple method for the conversion of methyl substituted pyridinium salts into 2,4,6-triarylphenyl derivatives: The first (thio)pyrylium ring transformations with heterocyclic anhydrobases as carbon nucleophiles

The synthesis of 2,4,6-triarylphenylpyridinium perchlorates 3 from methyl substituted derivatives 2 by a 2,6-[C₅+C] ring transformation of 2,4,6-triaryl(thio)pyrylium salts 1/4 in the presence of triethylamine/acetic acid in ethanol is reported. Spectroscopic data of the pyridinium perchlorates 3 and their formation via anhydrobases of the salts 2 are discussed.     

Reactions of 1,5-diketones. 42. Synthesis of heterocycles by the reaction of 4,4-dimethyl-1-phenyl-1-(2′-oxocycloalkyl)-3-pentanones with nitrogen-containing nucleophiles

The reaction of 1,5-diketones containing a pivaloyl fragment with several nitrogen-containing nucleophiles was studied. Derivatives of 2-tert-butyl-1,4-dihydropyridine were obtained and the direction of heterocyclization upon the reaction of these diketones with primary amines containing an additional nucleophilic site was elucidated. The facile free-radical cleavage of the angular tert-butyl group was demonstrated.     

含氟芳杂环化合物的合成II: 3,5-二硝基-4-氯三氟甲苯和3,5-二硝基-2-氯三氟甲苯与含氮亲核试剂的反应

本文报道了3,5-二硝基-4-氯代苯并三氟化物和3,5-二硝基-2-氯代苯并三氟化物与含氯亲核试剂的反应, 并用于合成诸如5,10-二氢-1-硝基-3-三氟甲基吩嗪和2-(O-氟代苯基)-4-硝基-6-三氟甲基苯并咪唑等含氟芳香族和杂环化合物, 讨论了反应条件对产品生成的影响.