Structures and reactivities of benzo-1,2,3-dithiazolium salts and their selenium analogs

A number of benzo-1,2,3-dithiazolium chlorides (I) and their selenium analogs — benzo-1,2,3-thiaselenazolium, benzo-2,1,3-thiaselenazolium, and benzo-1,2,3-diselenazolium salts — were synthesized. The electronic structures and reactivities of the I cation and salts I–IV are discussed on the basis of a quantum-chemical calculation of cation I and the PMR spectra of salts I–IV. Successive substitution of the sulfur atoms in the I cation by selenium atoms, particularly in the 2 position, substantially increases the degree of transfer of positive charge to the condensed benzene ring. The trend of the nucleophilic reactivities of 6-methoxy derivatives of salts I–IV in the reaction with aromatic amines is the same as the trend of the degree of localization of the positive charge in the 6 position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 912–916, July, 1978.     

Synthesis and some properties of benzo-1,2,3-thiaselenazolium salts

The reaction of selenious acid on benzo-1,2,3-dithiazolium salts (Herz salts) gives benzo-1,2,3-thiaselenazolium salts, which were previously obtained from o-aminothiophenols. This reaction, which involves exchange of sulfur by selenium in the heteroring, occurs only under conditions in which the products of hydrolysis of the Herz salts —benzo-3H-1,2,3-dithiazole 2-oxides- are in equilibrium with them.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1361–1364, October, 1976.     

Reaction of benzo-1,2,3-dithiazolium salts with aromatic amines

The character of a displaceable group depends substantially on the rate of reaction of substituted 6-chloro and 6-methoxy derivatives of benzo-1,2,3-dithiazolium salts, which gives the corresponding 6-phenylaminobenzo-1,2,3-dithiazolium salts. In 4,6-disubstituted benzo-1,2,3-dithiazolium salts, an aniline residue displaces only the substituent in the 6 position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 183–185, February, 1976.     

Conversion of 4-substituted benzo-2,1,3-thiadiazoles to 5-chloro-4,7-dioxobenzo-2,1,3-thiadiazole by action of hydrogen peroxide and hydrochloric acid

Under the influence of hydrogen peroxide and hydrochloric acid in acetonitrile 4-substituted benzo-2,1,3-thiadiazoles form 5-chloro-4,7-dioxobenzo-2,1,3-thiadiazole. 4-Alkoxy- and 4-[(alkoxycarbonyl)methoxy]benzo-2,1,3-thiadiazoles give, in addition, the corresponding 5,7-dichloro derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 114–117, January, 1988.     

Reactions of 4-cyanobenzo[<Emphasis Type="Italic">c</Emphasis>]pyrylium salts with nitrogen-containing nucleophiles

The recyclization reactions of 4-cyanobenzo[c]pyrylium salts with ammonia, primary amines, and hydrazines have been studied. New derivatives of isoquinoline, benzo-2,3-diazepine, and pyrazolo-[ 5,4-c]isoquinoline have been obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1645–1651, November, 2004.     

Disulfides of the benzo-2,1,3-thiadiazole series

Disulfides of the benzo-2,1,3-thiadiazole series were obtained by reduction of benzo-2,1,3-thiadiazolesulfonyl chlorides (by hydriodic acid or by sulfur dioxide) or by the reaction of benzo-2,1,3-thiadiazolesulfinic acids with hydrogen bromide in acetic acid. Convenient methods for the synthesis of the starting compounds were found, and the fungicidal activity of the disulfides obtained was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1555–1558, November, 1989.     

Studies in the field of 2,1,3-thia- and -selenadiazoles

The results of studies on 2,1,3-thiadiazole, benzo-2,1,3-thiadiazole, benzo-2,1,3-selenadiazole, and their derivatives by chemical, physicochemical, and physical methods give no grounds for assuming that they have a quinoid structure. These results permit the statement that these heterocycles containing quatervalent sulfur or selenium are typical heteroaromatic systems satisfying Hückel's (4n+2) rule.For part LV, see [1].     

Studies in the field of 2,1,3-thia- and selenadiazoles

The reaction of benzo-2,1,3-thiadiazole with hydroxylamine sulfate in concentrated sulfuric acid at 150° C for 1–10 hr has been studied. It has been shown that under these conditions mixtures of different amounts of 4- and 5-aminobenzo-2,1,3-thiadiazoles are formed.For part LII, see [1].     

Investigations of 2,1,3-thia- and selenadiazole s

All of the possible isomeric monoaminobenzo-2,1,3-selenadiazoles are formed in the reaction of benzo-2,1,3-selenadizaole 4- or 5-irethyl-, or 5,6-dimethylbenzo 2,1,3-selenadiazoles with hydroxylaminesulfate in concentrated sulfuric acid.See [1] for communication LXV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 328–330, March, 1972.     

The potential use of 6-amino-5-methoxy(methyl)-2,3-dimethyl-and 6-amino-5-methoxy(methyl)-1,2,3-trimethyl-indoles in the synthesis of pyrrolo[2,3-f]quinolines

The reaction of 6-amino-2,3-dimethyl-and 6-amino-1,2,3-trimethyl-5-methoxy(methyl)indoles with 4,4,4-trifluoroacetoacetic ester and of 6-amino-5-methoxy-1,2,3-trimethylindole also with other β-dicarbonyl compounds has been studied. It was found that all of the amines investigated undergo condensation readily to form the corresponding enamines while the possible subsequent cyclization to give pyrrolo[2,3-f]quinolines was found only for the condensation product of 6-amino-2,3,5-trimethylindole with 4,4,4-trifluoroacetoacetic ester. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp 97–103, January, 2006.     

2-Benzopyrylium salts

The properties of 1,3-dimethyl-6,7-dialkoxy-2-benzopyrylium salts were studied. The heterocyclic oxygen atom is readily replaced by nitrogen by reaction of the 2-benzopyrylium salts with primary amines, hydrazine, phenylhydrazine, glycine ethyl ester, and hydroxylamine; reaction with secondary amines leads to naphthalene derivatives. The activities of the methyl groups in the 1 and 3 positions of the heterocyclic ring are compared.For Communication IX, see [6].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1308–1312, October, 1970.     

Ambidentate reactivity of 3-azapyrylium systems in nucleophilic attack reactions

It has been shown that recyclization of 4-acylmethyl-3-azapyrylium salts under the influence of primary amines affords 4-(-hydrozystyryl)pyrimidinium salts, which, upon further heating with the amine, are recyclized to form 4-acylaminopyridinium salts. It has been established that nucleophilic attack of 6-acylmethyl-substituted 3-azapyrylium salts in aqueous NaOH solution leads to functionally substituted pyridines. By means of MNDO quantum-chemical calculations with an accounting for solvation effects, in a continuum model, it has been shown that two directions of nucleophilic attack of the azapyrylium ring — at positions 2 and 6 — are equally probable.Rostov State University. Scientific-Research Institute of Physical and Organic Chemistry, Rostov State University, Rostov-on-Don 344010. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 697–700, May, 1994. Original article submitted April 18, 1994.     

Syntheses in the benzo-2, 1,3-thiadiazole series. II. Derivatives of 1,2,5-thiadiazolo]3,4-h]quinoline and benzo-2, 1, 3-thiadiazolo]4, 5-h]-1,6-naphthyridine

Derivatives of l,2,5-thiadiazolo[3,4-h]quinoline and benzo- 2,1,3-thiadiazolo-[4, 5-h]-1, 6-naphthyridine were synthesized from 4-aminobenzo-2, 1, 3-thiadiazole.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 61–64, January, 1976.     

Synthesis of indoles from pyridinium salts. 6. Reaction of 3-nitroquinolinium salts with ketones in the presence of amines

It is shown that in the reaction of 3-nitroquinolinium salts with aliphatic ketones and amines the ketone adds to the 2 and 4 positions with the formation of tricyclic adducts — benzazabicyclononane derivatives. Their conformational analysis was carried out on the basis of the NMR spectral data. Intermediate products of the monoaddition of ketones in the 4 position of the heteroring were isolated for the unsubstituted 3-nitroquinolinium salt.See [1] for Communication 5.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1385–1393, October, 1988.     

Synthesis of indoles from pyridinium salts 5. Secondary amines in the reaction of 3-nitropyridinium salts with acetone

The use of secondary amines in the reaction of 3-nitropyridinium salts with acetone makes it possible to isolate stable intermediates in the formation of indoles — (o-N,N-dialkylaminobenzyl)ketones — and to observe new reaction pathways — the formation of bisindolylpropanes and p-nitroanilines.See [1] for Communication 4.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1213–1221, September, 1988.     

Synthesis of alkynylbenzo-15-crown-5 ethers

Reactions of 4"-iodobenzo-15-crown-5 ether with ethynylarenes or 4"-ethynylbenzo-15-crown-5 ether with haloarenes in the presence of catalytic amounts of Pd^IIcomplex salts, CuI, and Et₃N gave 4"-(arylethynyl)benzo-15-crown-5 ethers in 55—80% yields.     

1,2,3-Oxadiazole rings in the aromatic compounds: A quantum-chemical investigation

Quantum chemical method PBE0/cc-pVTZ in conjunction with the polarizable continuum model (PCM) was applied to the calculation of the equilibrium structural parameters of the benzene and naphthalene 1,2,3-oxadiazole derivatives, as well as relevant diazocarbonyl compounds both in the free state and dissolved in dichloromethane. The calculated ionization potentials of benzo-1,2,3-oxadiazole (9.49 eV), 6-diazocyclohexa-2,4-dien-1-one (8.16 eV) and (6-oxocyclohexa-2,4-dien-1-ylidene)carbonyl (8.34 eV) differ from the experimental values no more than by 0.09 eV. The calculations indicate the possible existence of naphtho [2,3-d:6,7-d′]bis(1,2,3-oxadiazole) in the gas phase and in aprotic solvents.     

The electron-impact-induced fragmentation of 1,2,3-benzotriazoles and some related compounds

The mass spectra of 1,2,3-benzotriazole and some derivatives with substituents at the 1-position and in the benzenering have been examined. The loss of N₂from the molecularion is characteristic; loss of N₂ plus the 1-substituent is also common. Structures are proposed for these fragment ions. The relative ease of loss of N₂, NO and NS from the molecular ions of benzotriazole, 2,1,3-benzodiazole, 1,2,3- and 2,1,3-benzothiadiazoles is compared.     

Benzo-1,2,3-oxadiazole and 6-Diazocyclohexa-2,4-dienone: Structures and Relative Energies of Molecules

Structural parameters, IR spectra, ionization potentials, relative energies, isomerization barriers, and solvation energies have been calculated for the aromatic benzo-1,2,3-oxadiazole (prevalent tautomer in the gas phase) and zwitterionic 6-diazocyclohexa-2,4-dienone (prevalent tautomer in a polar solvent) molecules. Similar calculations indicated that unsubstituted 1,2,3-oxadiazole is unstable in all solvents.Original Russian Text Copyright © 2004 by S. G. Semenov and Yu. F. Sigolaev__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1128–1131, November–December, 2004.     

Synthesis of Substituted and Condensed Tetrahydrospiro[benzo-2-azepinecyclohexanes] from 1-Cyano- and 1-Carbamoyl-5-methyl-4,5-dihydro-3H-spiro[benzo-2-azepine-3,1′-cyclohexanes]

Substitution of the nitrile group by hydroxylamine and hydrazine has been effected in 1-cyanodihydrospiro[benzo-2-azepine-3,1′-cyclohexane]. From the 1-cyano and 1-hydrazino derivatives tetrahydrospiro{1,2,3- and 1,2,4-triazolo[5,1-a]benzoazepine-5,1′-cyclohexanes} have been obtained. It was established that 1-carbamoyldihydrospiro[benzo-2-azepine-3,1′-cyclohexanes] are converted under the conditions of the Hoffmann reaction into spiro{diaziridino[3,1-a]benzo-2-azepine-3,1′-cyclohexane{, and is reduced by sodium borohydride to the tetrahydro derivative. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1033–1037, July, 2005.