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.     

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.     

Potentially biologically active new substituted anilides of benzo[2,3-<Emphasis Type="Italic">b</Emphasis>]thiophene series

New substituted anilides of the heterocyclic series 2, 4, 5, 6, 7 together with the earlier described compounds 1 and 3 (Jarak I et al. (2005) J Med Chem 48:2346), were synthesized from the corresponding heterocyclic carbonyl chlorides, methoxycarbonyl- and cyano-substituted anilines. Compounds 2 and 7 were prepared by methylation with methyl-iodide on the amide and the pyridine nitrogen. The Pinner reaction was used in the preparations of amidino-substituted compounds. It seems that all the prepared compounds could be biologically interesting, especially amidino-substituted anilides prepared in the form of water-soluble hydrochlorides or hydroiodides. Molecular and crystal structures of the three compounds, namely, 4′-methoxycarbonyl-N-phenyl-3-chlorobenzo[b]thiophene-2-carboxamide (1), N-(4′-amidinophenyl)-3-chlorobenzo[b]thiophene-2-carboxamide hydrochloride monohydrate (4) and 1-methyl-N-(4-amidinophenyl)-3-pyridine carboxamide iodide hydroiodide (7) have been determined by X-ray single-crystal diffractometry in the solid state. Compounds 1, 4 and 7 are not planar and the amide group (C=O in relation to NH group) is in trans position in all three compounds. The 3-chlorobenzo[b]thiophene moiety in 1 and 4 is oriented with the chloro substituent in cis position in relation to amide NH group. The conformational characteristics of the compounds result from the introduction of different substituents or solvent molecules (water molecule in 4), which leads to various intermolecular hydrogen bonds formation (N–H⋯O, N–H⋯Cl, O–H⋯Cl⁻, N–H⋯I⁻) in 1, 4 and 7. Hydrogen bond formation could be responsible for the potential biological activity of the compounds.     

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 2,3-disubstituted derivatives of pyrano-, thiopyrano-, and benzoannelated pyrido[2,3-<Emphasis Type="Italic">b</Emphasis>]thieno[3,2-<Emphasis Type="Italic">d</Emphasis>]pyrimidines

A new methods have been developed for the synthesis of condensed pyrido[2,3-b]thieno[3,2-d]pyrimidines based on cyclic derivatives of 4-cyanopyridine-3-thiones. The presence of two different reactive functional groups NH₂ and CONH gives the possibility of carrying out different conversions of thieno[2,3-b]pyridines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, 1245–1252, August, 2008.     

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.     

4-(10-Methyl-10H-phenothiazin-3-yl)-1,4-dihydropyridines, 4,5-dihydroindeno[1,2-<Emphasis Type="Italic">b</Emphasis>]-and 5,5-dioxo-4,5-dihydrobenzo-thieno[3,2-<Emphasis Type="Italic">b</Emphasis>]pyridines

Different modifications of the Hantzsch synthesis using 10-methyl-10H-phenothiazine-3-carbaldehyde gave 4-(10-methyl-10H-phenothiazin-3-yl)-substituted 1,4-dihydropyridine-3,5-di-, 5-oxo-4,5-dihydro-1H-indeno[1,2-b]pyridine-, and 5,5-dioxo-4,5-dihydro-1H-5λ⁶-benzo[4,5]thieno[3,2-b]pyridine-3-carboxylic esters. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 280–288, February, 2007.     

Reactions of 1,3-dihydrobenzo[<Emphasis Type="Italic">c</Emphasis>]thiophene 2,2-dioxides with electrophilic agents

Nitration, sulfonation, and iodination of 1,3-dihydrobenzo[c]thiophene 2,2-dioxide and its derivatives with electron-releasing and electron-withdrawing substituents were studied. Electrophilic substitution in 1,3-dihydrobenzo[c]thiophene 2,2-dioxide occurs at position 5. The presence of electron-withdrawing substituents in this position hinders further substitution, while electron-releasing substituents in positions 5 and 6 direct an electrophile to position 4.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 428–431, February, 2005.     

Reaction of 2-alkylthio-6-amino-pyrimidin-4(3H)-ones with ethyl bromopyruvate. Synthesis of furo-[2,3-<Emphasis Type="Italic">d</Emphasis>]-pyrimidine and furo[3,2-<Emphasis Type="Italic">e</Emphasis>]imidazo-[1,2-<Emphasis Type="Italic">c</Emphasis>]pyrimidine carboxylates

Reaction of 2-alkylthio-6-aminopyrimidin-4(3H)-ones with ethyl bromopyruvate to give ethyl 2-alkyl-thio-4-aminofuro[2,3-d]pyrimidine-5-carboxylates has been shown to proceed under neutral or acidic conditions. The obtained furo[2,3-d]pyrimidines underwent further cyclocondensation reaction with ethyl bromopyruvate to afford diethyl 5-alkylthiofuro[3,2-e]imidazo[1,2-c]pyrimidine-2,9-dicarboxy-lates. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 440–443, March, 2009.     

Condensed isoquinolines 25. Alkylation of 6,11-dihydro-13H-isoquino[3,2-<Emphasis Type="Italic">b</Emphasis>]quinazolin-13-one

Interaction of 6,11-dihydro-13H-isoquino[2,3-b]quinazolin-13-one with alkylating agents occurs at two positions depending on their nature and the reaction conditions-at C₍₆₎ or N₍₅₎. Fusion with methyl tosylate leads to 5-methyl-13-oxo-6,13-dihydro-11H-isoquino[3,2-b]quinazolin-5-ium salts, while interaction with benzyl halides in the presence of i-PrONa gave 6-benzyl-and 6,6-dibenzyl-6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-ones. Alkylation with olefins led to two types of products. In the case of maleinimides and maleic acid anhydride Michael adducts at C₍₆₎ were formed and in the case of cyanocinnamic acid esters the reaction was accompanied by intramolecular acylation at N₍₅₎ to give 1-aryl-3,9-dioxo-3H,9H,11H-benzo[5,6][1,8]naphthyridino[1,8-ab]quinazoline-2-carbonitrile. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No.11, 1698–1708, November 2007.     

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.     

Ionic Liquid Promoted One-Pot Synthesis of Furo[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidine-2,4(1<Emphasis Type="Italic">H</Emphasis>,3<Emphasis Type="Italic">H</Emphasis>)-diones

Summary. The three-component condensation of aldehyde, N,N′-dimethylbarbituric acid and alkyl or aryl isocyanide afforded the corresponding furo[2,3-d]pyrimidine-2,4(1H,3H)-diones in 1-butyl-3-methylimidazolium bromide as an ionic liquid in high yields at room temperature within several minutes.     

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.     

Crystal and molecular structure of new tetrahydrobenzo[<Emphasis Type="Italic">e</Emphasis>]pyrano[4,3-<Emphasis Type="Italic">b</Emphasis>]pyridines

Three tetrahydrobenzo[e]pyrano[4,3-b]pyridines formed in a diethyl 2,4,6-trioxoheptanedicarboxylic ether-substituted salicylic aldehyde-ammonium acetate system were studied by single crystal X-ray diffraction. After the introduction of a methoxy group in the tricyclic system, the tetrahydropyridine and pyrane rings adopted the half-chair conformation, while in the unsubstituted compound, the tetrahydropyridine ring has a distorted boat conformation, and the pyrane ring has a C-envelope conformation. In the compounds, the N-H?O and O-H?O intermolecular hydrogen bonds give rise to the development of chain structures. In two of the three compounds examined, the hydrogen atoms at the chiral centers are in the trans-position, as in the structure of natural tetrahydrocannabinols.