Synthesis of 2-phenylthieno[3,2-d]oxazole and 2-phenylthieno[3,2-d]thiazole

2-Phenylthieno[3,2-d]oxazole and 2-phenylthieno[3,2-d]thiazole were obtained by cyclization of the corresponding 2-phenyloxazole and 2-phenylthiazole derivatives. Their spectra and chemical properties were studied, and the pK_a values of carboxylic acids with other two-ring systems with a condensed thiophene ring were also compared.See [1] for our preceding communications.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 474–476, April, 1979.     

Synthesis of 2-methyl-5-phenylthieno[2,3-d]thiazole

The synthesis of a new heterocyclic base — 2-methyl-5-phenylthieno[2,3-d]thiazole — is described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, 1624–1625, December, 1970.     

Synthesis of 2-R-fluorantheno[2,3-d]- and 2-R-fluorantheno[3,2-d]oxazoles

2-R-Fluorantheno[2,3-d]- and 2-R-fluorantheno[3,2-d]oxazoles were synthesized, and their UV and IR spectra were studied. Ten new compounds are described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 905–907, July, 1974.     

Synthesis of New Furo[2,3-b]pyridine and Furo[3,2-d]pyrimidine Derivatives

Russian Journal of Organic Chemistry - New furo[2,3-b]pyridine and pyrido[3′,2′:4,5]furo[3,2-d]pyrimidine derivatives were synthesized from ethyl...     

New Synthesis of Pyrido[2,3-d] and [3,2-d]Oxazines

N-Hydroxyquinolinimide 1 reacts with each of aromatic amines, hydrazine hydrate and aromatic hydrocarbons to give arylcarbamoyl pyridines 2, pyrrolopyridines 3, pyridopyridazines 4 and pyridooxazinones 5 and 6. The heterocycles 5 and 6 can be transformed to the condensed systems, triazolopyridopyridazines 14 and 15 through series of reactions.     

Synthesis of 2 -methylthieno [2, 3-b] thieno [ 2, 3-d] thiazole

The synthesis of a new heterocyclic base, 2-methylthieno[2, 3-b]thieno[2, 3-d]thiazole, is described. It is obtained by oxidizing 2-thioacetylamino[2, 3-b]thiophene in alkaline medium with 10% aqueous potassium ferricyanide.     

Synthesis of 2-mercapto-substituted thieno[2,3-d]thiazoles and ben zothieno[3,2-d] thiazoles

2-Mercaptothieno[2, 3-d]thiazoles were synthesized from bis(2-nitro-3-thienyl) disulfide by successive reduction of, initially, the disulfide bond and the nitro group in the presence of carbon disulfide without isolation of the intermediate 2-nitro-3-mercaptothiophene. 2-Mercaptobenzo-[b]thieno[3, 2-d]thiazole was synthesized by reaction of 3-aminobenzo[b]thiophene hydrochloride with sulfur monochloride and cleavage of the resulting benzo[b]thienothiazothionium chloride with sodium sulfide in the presence of carbon disulfide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1355–1356, October, 1976.     

Convenient synthesis and anticancer evaluation of novel pyrazolyl-thiophene,thieno[3,2-b]pyridine,pyrazolo[3,4-d]thieno[3,2-b]pyridine and pyrano[2,3-d]thieno[3,2-b]pyridine derivatives

The newly synthesized 3-(3-amino-5-(phenylamino)-4-(phenylcarbamoyl)thiophen-2-yl)-3-oxopropanoate was utilized as a precursor for the synthesis of pyrazolyl-thiophene derivative, which undergoes cyclization upon treatment with benzaldehyde derivatives to provide pyrazolo[3,4-d]thieno[3,2-b]pyridines. Basic treatment of pyrazolyl-thiophene derivative with phenyl isothiocyanate followed by subsequent addition of chloroacetone and/or ethyl bromoacetate yielded the thiazolylidene-pyrazolyl thiophenes. In addition, the building block 3-(3-amino-5-(phenylamino)-4-(phenylcarbamoyl)thiophen-2-yl)-3-oxopropanoate was converted into the corresponding thieno[3,2-b]pyridine compounds through its reactions with (DMF-DMA) and/or heating in sodium ethoxide. Moreover, the reaction of 7-hydroxy-5-oxo-N-phenyl-2-(phenylamino)-4,5-dihydrothieno[3,2-b]pyridine-3-carboxamide with 2-arylidenemalononitrile produced the new annulated pyrano[2,3-d]thieno[3,2-b]pyridines. The prepared thiophene-based compounds were evaluated against HepG2, PC3, and MCF-7 cancer cells, and normal fibroblast cell (WI38). The pyrazolo[3,4-d]thieno[3,2-b]pyridine and pyrano[2,3-d]thieno[3,2-b]pyridine compounds substituted with chlorophenyl group presented promising cytotoxic activities against HepG2 cancer cell line without any human toxicity. Docking study for the synthesized thiophene compounds delivered valuable insights about the binding interactions with the crystal structure of NS5B enzyme with PDB ID (4TLR).     

Synthesis of new thienocyclopenta[3,2-d]-oxazole and thiazole derivatives

Synthesis of thieno[2′,3′:5,4]cyclopenta[3,2-d]oxazole and thiazole derivatives are achieved by insertion of carbon dioxide and disulfide into 4-amino-5-chloro-5,6-dihydro-4H-cyclopenta[b]thiophen-6-one.     

Synthesis of substituted thieno[2,3-d]thiazoles and indolo[3,2-d]thiazoles

Alkylene-, halo-, and aryl-substituted 2-methylthieno[2,3-d]thiazoles were obtained by the action of phosphorus pentasulfide on the corresponding 2-acetylamino-3-bromo- or 2-acetylamino-3-hydroxythiophenes in an organic solvent with heating. 2-Oximes of halo- and methyl-substituted isatins were converted by reduction and acylation into 2-hydroxy-3-acetylaminoin-doles, from which 2-methylindolo[3,2-d]-thiazoles were obtained by the action of phosphorous pentasulfide with heating in xylene.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 410–417, March, 1987.     

Synthesis of 2-mercaptothieno[3,2-d]- and 2-mercaptobenzo[4, 5]thieno[2,3-d]thiazoles

2-Mercaptothieno[3,2-d]- and 2-mercaptobenzo[4, 5]thieno[2,3-d]thiazoles were synthesized by reduction of bis(3,3′-nitro-2,2′-thienyl) and bis(2,2′-nitrobenzo[b]thien-3,3′-yl) disulfides, respectively, with sodium hydrosulfite or sodium sulfide in the presence of carbon disulfide.     

Tetracyclic systems: Synthesis of isoindolo[1,2-b]thieno-[2,3(3,2 or 3,4)-e][1,3]thiazocines and Isoindolo[2,1-a]thieno-[2,3(3,2 or 3,4)-f][1,4] and [1,5]diazocines

Cyclization of thioglycolic acids derivatives 3a-d gave isoindolo[1,2-b]thieno[2,3(3,2 or 3,4)-e][1,3]-thiazocines 4a-d . Isoindolo[2,1-a]thieno[2,3(3,2 or 3,4)-f][1,4] or [1,5]diazocines 10b or 11a-c were synthesized from Beckmann or Schmidt rearrangement of the ketones 7a-c .     

Selenium heterocycles XXVII . Synthesis of Thieno[2,3-d] thiazole and Selenolo[3,4-d]thiazole. Two novel heterocycles

Starting from the readily available aryl 2-substituted-4-methyl-5-thiazolyl ketones, a series of 2,6-disubstituted-thieno[3,4-d]thiazoles and 2,6-disubstituted-selenolo[3,4-d]thiazoles were prepared. The structures of these compounds were confirmed by analytical, spectroscopic methods and through the reaction with dimethyl acetylenedicarboxylate.     

Synthesis of 4,4,5-trimethylthieno[2,3-b]pyrrolenine and 5,6,6-trimethylthieno[3,2-b]pyrrolenine

New heterocyclic bases—4,4,5-trimethylthieno[2, 3-b]pyrrolenine and 5, 6, 6-trimethylthieno[3,2-b]pyrrolenine—have been obtained by the condensation of the double salts of stannic chloride and the hydrochlorides of, respectively, 2- and 3-aminothiophenes with methyl-hydroxyisopropyl ketone and methyl-bromoisopropyl ketone.     

Polymethine dyes — Indolo[3,2-d]thiazole derivatives

New polymethine dyes with an indolo[3,2-d]thiazole residue are described, and their spectral properties are discussed. Replacement of the vinylene group in the naphtho[1,2-d]thiazole residue by an NH group leads to a considerably greater bathochromic shift of the absorption maximum of carbo- and merocyanines as compared with replacement by a sulfur atom. The basicity of the indolo[3,2-d]thiazole residue is higher than the basicity of the naphtho[1,2-d]-thiazole and thionaphtheno[3,2-d]thiazole residues.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1606–1610, December, 1972.     

Synthesis of 2-Carbamoylthieno[3,2-d]thiazoles

A preparation procedure was developed for previously unknown 2-carbamoylthieno[3,2-d]-thiazoles consisting in cyclization effected by K₃Fe(CN)₆ of monothiooxamides obtained from 2-methyl-4-aminothiophene, chloroacetamides, and sulfur in the presence of triethylamine.     

Synthesis of 2-methylphenanthro[2, 1-d]thiazole

2-Methylphenanthro[2, 1-d]thiazole has been synthesized by the oxidative cyclization of 2-thioacetylaminophenanthrene.     

New method for the synthesis of substituted thieno[3,2-b]pyridines and 5H-pyrano[2,3-d]thieno[3,2-b]pyridines derived from them

A new highly selective method was developed for the synthesis of substituted thieno[3,2-b]-pyridines based on the domino reaction of monopotassium salt (rather than dipotassium one) of carbamoylcyanodithioacetic acid with ethyl 4-chloroacetoacetate. Substituted 5H-pyrano[2,3-d]-thieno[3,2-b]pyridines were synthesized based on these thieno[3,2-b]pyridines.     

A concise synthesis of functionalized 2,3-dihydrofuro[3,2-b], [3,2-c], and [2,3-b]pyridines

A strategy for the efficient and rapid one-pot synthesis of 2-aryl-2,3-dihydrofuro[3,2-b], [3,2-c], and [2,3-b]pyridines from readily available o-nitropicolines and aromatic aldehydes is described. The key transformation involves reaction of o-nitropicolines with aromatic aldehydes in the presence of TBAF and Hünig's base giving rise to functionalized products having molecular complexity suitable for further manipulation.     

Selenium heterocycles. XXVIII . Synthesis of pyrrolo[3,2-d]selenazole and pyrrolo[3,2-d|thiazole. Two novel heterocycles

Starting from the readily available 2-substituted-4-formylselenazoles and 2-substituted-4-formylthiazoles, a series of substituted-pyrrolo[3,2-d]selenazoles and substituted-pyrrolo[3,2-d|-thiazoles were prepared respectively.