Condensed heterocycles with a thiazole ring. 15. Dyes based on thiazolo[3,4-b][1,2,4]triazine

Unsymmetrical tri- and pentamethinecyanine dyes with a thiazolo[3,4-b][1,2,4]triazine ring were synthesized. The electron-density distribution on the atoms of the dyes in the ground, first, and second excited states was calculated by a quantum-chemical method. It was established that the first two electron transitions are localized on the same atoms of the dyes and that charge transfer to the triazine fragment of the molecule is realized upon excitation. The degree of participation of the heterocyclic ring in the first electron transition, which is responsible for the color of the dye, decreases with an increase in the length of the polymethine chain.See [1] for Communication 14.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 985–991, July, 1988.     

Condensed heterocyclic compounds containing a thiazole ring. 12. Derivatives of thiazolo[3,4-b][1,2,4]triazine

Unsymmetrical monomethinecyanine dyes, containing a benzothiazole residue, were obtained from thiazolotriazine. To interpret the nature of the main absorption bands and localize the electronic transitions, the transition energies and electronic distribution of the first and second excited states of several model compounds were calculated by the self-consistent field method.For Communication 11, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1693–1697, December, 1986.     

Condensed heterocycles with a thiazole ring. 10. Thiazolo[3,4-b][1,2,4]triazines

Derivatives of a new heterocyclic system, viz., the thiazolo[3,4-b][1,2,4]triazinium ion, were obtained by condensation of cyanobenzyl benzenesulfonate with substituted N-dithiocarboxyhydrazones of 1,2-diketones and -isonitroso ketones.See [1] for communication 9.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 498–501, April, 1985.     

Condensed heterocycles with a thiazole ring. 2. Monomethylidynecyanine dyes of the thiazolo[3,4-a]pyrimidine series

Unsymmetrical monomethylidynecyanine dyes that contain benzothiazole or quinoline residues were obtained on the basis of thiazolopyrimidine. The energies of the transitions and the electron distributions in the ground, first, and second excited states were calculated for several of the dyes obtained and for model compounds by the self-consistent-field configuration-interaction (SCF CI) method in order to interpret the first absorption bands and determine the localization of the electron transitions.See [1] for communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 639–643, May, 1982.     

Condensed heterocycles with a thiazole ring. 16. Cyanine dyes based on thiazolo[3,4-a]pyridinium salts

The reaction of 2-(-chlorobenzyl)pyridines with thioacetamide gave 3-methyl-1-arylthiazolo[3,4-a]pyridinium salts, which form cyanines. It was established that the thiazolopyridinium ring in the dyes has high electron-donor character and a great effective length.See [1] for Communication 15.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1274–1277, September, 1988.     

Condensed heterocycles with a thiazole ring. 1. Thiazolo[3,4-a]pyrimidine derivatives

It is shown that the reaction of 1,3-dicarbonyl compounds or their acetals with 2-methylthio-4-amino-5-phenylthiazolium benzenesulfonate gives 6-methylthiothiazolo[3,4-a]pyrimidinium salts, which react with the appropriate intermediates to give polymethine dyes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 634–638, May, 1982.     

Condensed heterocycles with a thiazole ring.

Derivatives of new condensed heterocyclic systems — pyrido- and quinolino[1,2:3,2]thiazolo[4,5-b]pyrazines — were synthesized by condensation of 2,3-dichloropyrazine with 2-mercaptopyridine and 2-mercaptoquinolines.See [1] for Communicaton 17.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1276–1278, September, 1990.     

Synthesis and reactions of 3-aminothiazolidine-2-thion-4-one derivatives. 5. Polymethine dyes of the thiazolo[3,4-b][1,2,4]triazole series

It is shown that the reaction of thiazolo[3,4-b][1,2,4]triazole-5-thiones with alkylating agents gives 5-methylthiothiazolotriazolium salts, which react with the appropriate intermediates to give polymethine dyes.See [1] for Communication 4.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 480–483, April, 1982.     

Condensed heterocyclic systems with a thiazole ring. 11. Thiazolo [3,4-b]-1,2, 4-triazinones

Syntheses are reported for substituted 2-oxo-1,2-dihydrothiazolo[3,4-b]-1,2,4-triazinium salts. The action of bases on these salts leads to the corresponding mesoionic compounds.For communication 10, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1497–1500, November, 1985.     

Condensed Isoquinolines. 14. Spirocyclic Systems Containing a Benzo[5,6][1,2,4]thiadiazino[4,3-b]isoquinoline Ring

We propose a convenient preparative method for synthesis of derivatives of novel heterospirane systems with a benzo[5,6][1,2,4]thiadiazino[4,3-b]isoquinoline ring, based on the reaction of 1-(2-bromomethylphenyl)-1-cyclopentanecarbonitrile and 4-(2-bromomethylphenyl)-3,4,5,6-tetrahydro-2H-pyran-4-carbonitrile with o-aminobenzenesulfamide.     

Synthesis of 1,2,4-triazole, 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole and 1,2,4-triazolo[3,4-b][1,3,4]thiadiazine derivatives of benzotriazole

A novel series of 1-(1-carbonylmethyl-1H-benzotriazole) thiosemicarbazides 3a-e was synthesized and then cyclized with sodium hydroxide to afford 1-(4-substituted-4H-1,2,4-triazole-3-thion-5-yl)methyl-1H-benzotriazoles 4a-e , which were alkylated with ethyl iodide to l-(3-ethylthio-4-substituted-4H-1,2,4-triazol-5-yl)-methyl-1H-benzotriazoles 5b-e . The reaction of 1H-benzotriazol-1-acetic acid hydrazide ( 2 ) with carbon disulphide and potassium hydroxide followed by hydrazine hydrate gave 1-(4-amino-4H-1,2,4-triazole-3-thion-5-yl)methyl-1H-benzotriazole ( 6 ). Its subsequent condensation with carboxylic acids in the presence of phosphorus oxychloride or with phenacyl bromides afforded two series of fused heterocycles namely; 6-substituted-3-[1-(1H-benzotriazole)methyl]-1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles 7a-e and 6-substituted phenyl-3-[1-(1H-benzotriazole)methyl]-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines 8a-e respectively. The structure of the newly synthesized compounds was elucidated by elemental analyses, ir and nmr spectra.     

Condensed heterocycles with a thiazole ring. 13. Azinothiazoloquinoxalinium salts

The condensation of 2,3-dichloroquinoxaline with 2-mercaptopyridines and 2-mercaptoquinolines gave the corresponding derivatives of new heterocyclic systems, viz., azino[1,23,2]thaizolo[4,5-b]quinoxalinium salts, which can be used for the synthesis of cyanine dyes.See [1] for Communication 12.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 551–553, April, 1987.     

1,2,4-Triazines. Synthesis of selected members of the s-triazolo[3,4-f]- [1,2,4] triazine and tetrazolo[1,5-f] [1,2,4] triazine ring systems

A convenient synthesis of 3-amino-6-hydrazino-5(2H)[1,2,4]triazinone 4 has been developed and a study of the reactions of 4 with aliphatic acids, orthoesters and miscellaneous active carbonyl reagents has been undertaken. When 4 was refluxed in either neat acid or orthoester in dimethylformamide, a facile ring closure reaction with the N-1 nitrogen of the 1,2,4-triazine ring occurs affording a novel series of 3-aIkyl(aryl)-8(5H)-s-triazolo[3,4-f] [1,2,4]triazinones ( 6–11 ). Ring closure with carbon disulfide and cyanogen bromide is also reported affording 6-amino-3(2H)thio-8(5H)-s-triazolo[3,4-f] [1,2,4]triazinone 12 and 3,6-diamino-8(5H)-s-triazolo-[3,4-f] [1,2,4]triazinone 14 , respectively. In addition 4 has been converted into 3-amino-6-azido-5(2H)-1,2,4-triazinone 15 which was employed in a study of azide-tetrazole equilibrium affording 6-amino-8(5H)tetrazolo[1,5-f][1,2,4]triazinone 16 . Rates for interconversion at various temperatures were measured and an activation energy for the process determined.     

Mass spectra of imidazo[2,1-b]thiazole and thiazolo[3,2-f]xanthene derivatives

The general principles of the mass-spectrometric disintegration of imidazo [2,1-b]thiazole and thiazolo[3,2-f]xanthene derivatives were established, and the characteristic fragments were identified. Disintegration proceeding with cleavage of the bonds in the thiazole ring of the 2(3)-ring system is characteristic of all of the investigated compounds. The cleavage of the S-C bonds, which are the weakest in the investigated systems, proceeds especially readily. Intense peaks of ions due to stepwise disintegration of the pyrimidine ring are also observed in the spectra of thiazoloxanthenes.     

Condensed 1,3-benzothiazinones 3. Synthesis of 3-substituted 1,2,4-triazolo[3,4-b][1,3]benzothiazin-5-ones

Refluxing 2-hydrazono-3,4-dihydro-2H-1,3-benzothiazin-4-one 3 with triethyl orthoformate neat or with trimethyl orthoformate 4a , triethyl orthoacetate, orthopropionate, orthobenzoate 4b-d in xylene gave 1,2,4-triazolo[3,4-b][1,3]benzothiazin-5-one 2a and its 3-substituted derivatives 2b-d in 56–95% yields. On the other hand, when 3 was treated with trifluoro-, trichloroacetic anhydride 4e,f , dichloro-, chloroacetyl chloride 4g,h , 2-chloropropionyl and ethoxyoxalyl chloride 4i,j , the corresponding open-chain condensates were produced, together with the title compounds 2g-i , or the Dimroth rearrangement isomers 1e,g,i,j each depending on the reaction conditions. Nevertheless efficient preparation of 2h and 3-hydroxy-derivative 2k to get rid of such rearrangement was developed.