Synthesis and reductive reactions of 2,3-dioxo-2,3-dihydrobenzo[<Emphasis Type="Italic">b</Emphasis>]furo[2,3-<Emphasis Type="Italic">f</Emphasis>]-, -[2,3-<Emphasis Type="Italic">g</Emphasis>]-, and -[3,2-<Emphasis Type="Italic">e</Emphasis>]indoles

The Sandmeyer reaction was used to prepare 2,3-dioxo-2,3-dihydrobenzo[b]furoindoles which could be reduced with diborane or with complex hydrides to give the corresponding unsubstituted as well as the 3-hydroxybenzo[b]furoindoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No 11, pp. 1683–1689, November, 2004.     

Synthesis and reactivity of thieno[2,3-<Emphasis Type="Italic">b</Emphasis>]pyridine-2,3-diamines

It has been established that the interaction of N¹-(2-hydroxyphenylmethylthieno[2,3-b]pyrid-3-yl)arylamides with hydrazine hydrate leads to thieno[2,3-b]pyridine-2,3-diamines. It was shown that the reaction of the latter with acetylacetone and acetoacetic ester occurs regioselectively at the amino group in position 3 of the thiophene ring. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1400–1408, September, 2007.     

Structure and photochromism of 2-(<Emphasis Type="Italic">N</Emphasis>-acyl-<Emphasis Type="Italic">N</Emphasis>-arylaminomethylene)benzo[<Emphasis Type="Italic">b</Emphasis>]thiophen-3(2<Emphasis Type="Italic">H</Emphasis>)-ones

It was shown by electron absorption spectroscopy and X-ray diffraction analysis that steric strains in photochromic 2-(N-acyl-N-arylaminomethylene) benzo[b]thiophen-3(2H)-one molecules ortho-substituted in the N-phenyl ring increase the quantum yield of the N→O photoinduced rearrangement in accord with an increase in the steric constant of the ortho-substituent.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2151–2155, October, 2004.     

Synthesis of 6-aryl-1,6-dihydrodipyrazolo[3,4-<Emphasis Type="Italic">b</Emphasis>:4,3-<Emphasis Type="Italic">c</Emphasis>]pyridines

6-Azido-1H-pyrazolo[3,4-b]pyridino-5-carbaldehydes react with aromatic amines to give the corresponding N-arylimines which cyclize on heating in boiling toluene to give 6-aryl-1,6-dihydrodipyrazolo[3,4-b:4,3-e]pyridines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, 1717–1722, November, 2004.     

Heterocyclic analogs of 5,12-naphthacenequinone 6. Synthesis of 4,11-dimethoxy derivatives of anthra-[2,3-<Emphasis Type="Italic">b</Emphasis>]thiophene-5,10-dione and anthra[2,3-<Emphasis Type="Italic">d</Emphasis>]isothiazole-5,10-dione

Condensation of 2-formyl-or 2-cyano-3-chloro-1,4-dimethoxyanthraquinone with methyl thioglycolate in the presence of base gave methyl 4,11-dimethoxyanthra[2,3-b]thiophene-5,10-dione-2-carboxylate and its 3-amino derivative respectively. Hydrolysis of the ester group in methyl 4,11-dimethoxyanthra[2,3-b]thiophene-5,10-dione-2-carboxylate and subsequent decarboxylation of the carboxylic acid formed gave 4,11-dimethoxyanthra[2,3-b]thiophene-5,10-dione. Condensation of 3-chloro-2-formyl-1,4-dimethoxyanthraquinone with ammonia in the presence of sulfur gave 4,11-dimethoxyanthra[2,3-d]isothiazole-5,10-dione __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 538–543, April, 2007.     

New method for the synthesis of thieno[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidines

The reaction of 5-formyl-4-thiocyanatopyrimidines with nitromethane was studied under various conditions. The reaction was found unexpectedly to proceed with closure of a thiophene ring to give thieno[2,3-d]pyrimidines. The use of ammonium acetate as the catalyst leads to a side reaction involving closure of an isothiazole ring to give isothiazolo[5,4-d]pyrimidines. X-ray diffraction crystallographic analysis was used to confirm the structure of thieno[2,3-d]pyrimidine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1564–1571, October, 2004.     

Synthesis and properties of (thieno[2,3-<Emphasis Type="Italic">b</Emphasis>]pyridin-3-yl)iminotriphenylphosphoranes. Molecular structure of (2-benzoyl-4-methoxymethyl-6-methylthieno[2,3-<Emphasis Type="Italic">b</Emphasis>]pyridin-3-yl)iminotriphenylphosphorane

Iminophosphoranes containing a thieno[2,3-b]pyridine fragment were obtained through a sequence of reactions: 1) alkylation of 3-cyano-2(1H)-pyridinethiones in alkaline medium by an -halocarbonyl compound with subsequent Thorpe-Ziegler cyclization of the resultant 2-thioalkylpyridines to give 3-aminothieno[2,3-b]pyridines, 2) diazotization of the amino group and nucleophilic substitution of the diazonium group by an azido group without isolation of the diazonium salts, and 3) reaction of the 3-azidothieno[2,3-b]pyridines with triphenylphosphine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1853–1862, December, 2004.     

Synthesis of Derivatives of 4,6-Dioxo-1,4,6,7,8,9-hexahydropyrimido[4,5-<Emphasis Type="Italic">b</Emphasis>][1,6]naphthyridines

It has been shown that 1-aryl-8-(4-bromophenyl)-4,6-dioxo-2H(phenyl)-7-phenyl-1,4,6,7,8,9-hexahydropyrimido[4,5-b][1,6]naphthyridines are formed on heating anilides of 1-aryl-7-(4-bromostyryl)-4-oxo-1,4-dihydropyrido[2,3-d]pyrimidine-6-carboxylic acids in PPA.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 597–600, April, 2005.     

Oxidative cyclocondensation of cyclic thio-and selenoureas. 5. 2-Thioxothieno-and 2-thioxopyrido[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidin-4-ones

A study was carried out on the oxidative cyclocondensation of 2-thioxothieno-and 2-thioxopyrido[2,3-d]pyrimidin-4-ones. The thiophene ring with excess π-electron density facilitates the reaction, while the pyridine ring with diminished π-electron density hinders it. 2-Thioxothieno-[2,3-d]pyridimin-4-ones were converted into previously unreported 7H,13H-[1,2,4]thiadiazolo-[3,2-b:5,4-b′]bis(thieno[2,3-d]pyridimine-7,13-diones). __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1424–1427, September, 2007.     

Synthesis of Some New Fused and Polyfused [1,2,4]Triazolo-[3,4-<Emphasis Type="Italic">b</Emphasis>][1,3,4]thiadiazepines

7-[1,3-Dithiolan-2-ylidene]-3-phenyl-5,6,7,8-tetrahydro[1,2,4]triazolo[3,4-b][1,3,4]thiadiazepine-6,8-dione and 7-[5-oxo-1,3-dithiolan-2-ylidene]-3-phenyl-5,6,7,8-tetrahydro[1,2,4]triazolo[3,4-b][1,3,4]-thiadiazepine-6,8-diones were obtained by treating 3-phenyl-5,6,7,8-tetrahydro[1,2,4]triazolo-[3,4-b][1,3,4]thiadiazepine-6,8-diones with CS₂ and chloroacetyl chloride, respectively. Treatment of the above compounds with mercaptoacetic acid gave 1,2-dibromoethane or the corresponding spiro polyfused heterocycles. Some other triazolothiadiazepine derivatives including spiro polyfused compounds were also synthesized. __________ Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 8, 1256–1264, August, 2005.     

Tandem transformations of tetrahydropyrrolo[3,2-<Emphasis Type="Italic">c</Emphasis>]pyridines under the action of dimethyl acetylenedicarboxylate. A novel route to pyrrolo[2,3-<Emphasis Type="Italic">d</Emphasis>]azocines

Reactions of substituted tetrahydropyrrolo[3,2-c]pyridines with dimethyl acetylenedicarboxylate in protic and aprotic solvents were studied. A novel single-step method for the synthesis of pyrrolo[2,3-d]azocine derivatives was developed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2513–2519, November, 2005.     

Investigations on 2,3′-biquinolines 22. Novel and convenient method for the synthesis of benzo[5,6]indolizino-[2,1-<Emphasis Type="Italic">b</Emphasis>]quinolinium-13-thiolates and benzo-[5,6]indolizino[1,2-<Emphasis Type="Italic">c</Emphasis>]quinoline-6(5H)-thiones

We have developed a method of synthesis of benzo[5,6]indolizino[2,1-b]quinolinium-13-thiolates and 5,6-dihydrobenzo[5,6]indolizino[1,2-c]quinoline-6-thiones based on the reaction of the corresponding 1′, 2′-dialkyl-1′,2′-dihydro-2,3′-biquinolines and 1′,4′-dialkyl-1′,4′-dihydro-2,3′-biquinolines with sulfur in DMF. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 849–851, June, 2007.     

Photochromic Dihetarylethylenes. 21. Synthesis and Photochemical Properties of 1,2-Bis{5-(2-benzothiazolyl)-2-ethylthieno-[2,3-<Emphasis Type="Italic">b</Emphasis>]thiophen-3-yl}Hexafluorocyclopentene

1,2-Bis{5-(2-benzothiazolyl)-2-ethylthieno[2,3-b]thiophen-3-yl}hexafluorocyclopentene has been synthesized for the first time. It was shown that, unlike analogous derivatives of thieno[3,2-b]thiophene, on irradiation with UV light (λ = 313 nm) it did not display photochromic properties, but undergoes an irreversible photoconversion which is accompanied by the display of intense fluorescence. This raises the prospect of using this compound for creating an irreversible photoluminescent recording medium.Dedicated to V. I. Minkin on his 70th birthday.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 360–364, March, 2005.For Part 20 see [1].     

Transformation of 1,2,3,7a-tetrahydroimidazo[1,2-<Emphasis Type="Italic">b</Emphasis>]isoxazole derivatives into isoxazoles

The reactions of 1,2,3,7a-tetrahydroimidazo[1,2-b]isoxazole derivatives with electrophilic reagents, such as protic acids, benzoyl chloride, BF₃, and bromine, produce isoxazole, 2,2,3,3-tetramethylaziridine, and 2,3,3-trimethylpropen-2-ylamine derivatives. Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1182–1187, June, 2007.