Hetarylation of pyrazolones by salts of N-acylheteroaromatic cations

Isoquinoline, acridine, benzimidazole, and benzoxazole residues were introduced into the pyrazolone ring by reaction of N-heteroaromatic compounds with pyrazolones in the presence of acylating agents.See [1] for our preliminary communication [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1394–1397, October, 1977.     

Structures of sterically hindered p-hydroxystyrylpyridines and acid-base transformations of their quaternary salts

The structures of p-hydroxystyrylpyridines and a number of their new quaternary salts were studied by means of electronic absorption spectra. The reverse transformation of the salts to the corresponding quinonoid compounds was examined as a function of the pH of the medium, and the equilibrium constants were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1087–1091, August, 1972.     

Ionization potentials of dipyridyls and diquinolyls

The ionization potentials of a number of isomeric dipyridyls and diquinolyls were determined. The differences in their values make it possible to establish the site of fusion of the rings in the 2,2, 3,3, and 4,4 positions of the system. The absence of an appearance potential for the fragment ion, the existence of which is due to cleavage of the interannular bond in the doubled hetaryl compounds, constitutes evidence for its double-bond character.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 812–814, June, 1976.     

Reactions of cycloammonium cations

2-Keto derivatives of N-acyl-1,2-dihydroquinoline and isoquinoline were obtained by the reaction of quinoline and isoquinoline with ketones and-dicarbonyl compounds in the presence of acyl halides. Under similar conditions, 9-phenacylacridines are formed by the reaction of acridine with acetophenones and acyl halides, while 5-acyl-6-phenacyl-5,6-dihydrophenanthridines are formed in the reaction of phenanthridine.See [1] for communication X.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 643–647, May, 1971.     

A Versatile Approach for Synthesis of 2,3-Dimethyl Chroman-4-ones,Intermediate for Calanolide Anti-HIV Agents,VIA Aldol/Mitsunobu Reactions

Combined aldol/Mitsunobu reactions have been employed for the first time for synthesis of 2,3-dimethyl chroman-4-ones, intermediates for calanolide anti-HIV agents. Thus, the lithium enolate of chromene 1 reacted with acetaldehyde at -78°C to afford the aldol products 4 and 5. Under Mitsunobu conditions (Ph₃P/DEAD), the syn aldol product 4 led to the formation of trans-2,3-dimethyl chroman-4-one 2 while the anti aldol product 5 yielded both trans and cis derivatives (2 and 3). The use of other phosphorous and azo compounds in this reaction has also been investigated.     

Direct heteroarylation of enamines

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 709–710, May, 1988.     

Reactions of cyclic ammonium cations

A method has been developed for the introduction of an isoquinolinium residue into an activated aromatic ring by means of N-acylisoquinolinium salts formed in the reaction of acyl halides with isoquinoline. 1-Substituted 2-acyl-1,2-dihydroisoquinolines with dialkylaniline, N-phenyl morpholine, N,N-diphenylpiperazine, 1-alkyl-1,2,3,4-tetrahydroquinoline, and 1-alkylindoline residues in the 1 position were synthesized via this route. The structures of the compounds obtained were proved by alternative syntheses.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 82–86, January, 1971.     

Reaction of indole with N-acylimmonium salts in situ

The possibility of direct amidomethylation of indole and some other organic compounds with N-acylimmonium salts formed by reaction of azomethines with acylating agents was observed.See [1] for a preliminary communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 493–496, April, 1976.