Synthesis and structure of derivatives of 7-aminobenzo[b]thiophene

Oximes of 2-acylamino-3-ethoxycarbonyl-7-oxo-4,5,6,7-tetrahydrobenzo[b]thiophenes have been prepared. A method for the synthesis of derivatives of 7-aminobenzo[b]thiophene is proposed and the hydrolysis of the compounds prepared has been studied.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1178–1180, September, 1986.     

Synthesis and structure of derivatives of 7-oxo-4,5,6,7-tetrahydrobenzo[b]-thiophene and 7-hydroxybenzo[b]thiophene

The oxidation of 2-acylamino-3-ethoxycarbonyl-4,5,6,7-tetrahydrobenzo[b]thiophenes gave the corresponding 7-oxotetrahydrobenzo[b]thiophenes and some of the transformations of these compounds were studied. These compounds were used for the synthesis of 3-ethoxycarbonyl-6-bromo-7-hydroxybenzo[b]thiophene. The structures of the compounds prepared were established by chemical and spectral methods.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1626–1629, December, 1984.     

Synthesis and Transformations of 3-Ethoxycarbonyl-2-(N-R-thioureido)thiophenes

3-Ethoxycarbonyl-2-(N-R-thioureido)-4,5,6,7-tetrahydrobenzo[b]thiophenes were obtained by the reaction of 2-amino-3-ethoxycarbonyl-4,5,6,7-tetrahydrobenzo[b]thiophene with isothiocyanates and of 3-ethoxycarbonyl-2-isothiocyanato-4,5,6,7-tetrahydrobenzo[b]thiophene with primary and secondary amines. The cyclization paths of the products leading to derivatives of thieno[2,3-d]pyrimidine and thieno[2,3-d]-1,3-thiazine were studied. The corresponding S-substituted derivatives were obtained by the alkylation of 3-R-2-thioxo-3,4,5,6,7,8-hexahydrobenzo[b]thieno[2,3-d]pyrimidin-4-ones.     

Lanthanum(III) chloride complexes with heterocyclic Schiff bases

Condensation of 2-amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene with carbonyl compounds such as isatin, o-hydroxyacetophenone or benzoin in 1:1 ratio in ethanol medium yielded three distinctly different heterocyclic Schiff bases viz. 2-(N-indole-2-one)amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene (ISAT), 2-(N-o-hydroxyacetophenone)amino- 3-carboxyethyl-4,5,6,7-tetrahydro-benzo[b]thiophene (HAAT) or 2-(N-benzoin)amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene (HBAT) respectively. These ligands formed well defined complexes with lanthanum(III) chloride under suitable conditions. The ligands and the complexes have been characterized on the basis of elemental analyses, molar conductance measurements, UV-visible, IR and proton NMR spectral studies. Kinetics and mechanism of the thermal decomposition of the ligands and the metal complexes have been studied using non-isothermal thermogravimetry. Kinetic parameters were calculated for each step of the decomposition reactions using Coats-Redfern equation. The rate controlling process for all the ligands and complexes is random nucleation with the formation of one nucleus on each particle (Mampel equation). Relative thermal stabilities of the ligands and the metal complexes have been compared.     

Synthesis of 6-phenylthiobenzo[b]thiophenes

A method of synthesizing 2-acetylamino-7-hydroxy-6-phenylthio-3-carbethoxybenzo[b]thiophenes from 6-phenylthio-7-oxo-4,5,6,7-tetrahydrobenzo[b]thiophenes has been developed. A method is also proposed for synthesis of 7-phenylthiobenzothieno[2,3-d]pyrimidines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 534–536, April, 1991.     

Synthesis of 2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]selenophene and some transformations based on it

A new method for the synthesis of 2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]selenophene was developed. The reaction of the latter with allyl isothiocyanate gave 2-(N-allylthioureido)-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]selenophene, which is cyclized to the potassium salt of 3-allyl-4-oxo-2-thio-3,4,5,6,7,8-hexahydrobenzo[b]selenopheno[2,3-d]pyrimidine on treatment with potassium hydroxide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 326–328, March, 1973.     

A NOVEL SYNTHESIS OF 2-SUBSTITUTED-4H-THIENO [2,3-d][1,3] OXAZIN-4-ONE AND 2,3-DISUBSTITUTED THIENO [2,3-d]PYRIMIDIN-4(3H)-ONE DERIVATIVES

Abstract

The synthesis of acetic 2-{[1-methyl-2-(4-oxo-5,6,7,8-tetrahydro-4H-benzo [4,5]-thieno [2,3-d] [1,3-oxazin-2-yl)ethylidene]amino}-4,5,6,7-tetrahydrohenzo[b]thiophene ?3-carboxylic acid anhydride 5 and 2-(oxopropyl)-5,6,7,8-tetrahydro-4H-benzo-[4,5] thieno[2,3-d][1,3]oxazin-4-one 7, has been achieved in three steps from ethyl 2-amino-4,5,6,7-tetrahydrobenzo(b]thiophene-3-carboxlate 1 via the reaction with ethyl acetoacetate followed by hydrolysis and acetic anhydride-induced cyclization. The 2-substituent in compound 5 has two functional groups i.e. active methylene and acid anhydride which are suitably located for intramolecular transformation. Thermal and/or base catalyzed intramolecular cyclization of 5 afforded 2-(4-acetoxy-(hydroxyl)-2-methyl-5,6,7,8-tetrahydrobenzo[4,5] thieno[2,3-b]pyridin-3-yl)-5,6,7,8- tetrahydro-4H-benzo[4,5]thieno[2,3-d] [1,3]oxazin-4-one 10 and 9 respectively. Treatment of 5 with hydrazine hydrate, aromatic and/or heterocyclic amines induced the same intramolecular cyclization with a concomitant oxazine-pyrimidine interconversion to give 3-amino(aryl or heteryl)-2-(4-hydroxy-5,6,7,8-tetrdhydrobenzo-[4,5]thieno[2,3-b]pyridin-3-yl)-3,4,5,6,7,8-hexahydrobenzo[4,5] thieno[2,3-d] pyrimid in-4-one 11–14 respectively.     

Synthesis,analgesic and antimicrobial activity of substituted 2-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-ylamino)-4-oxo-4-phenylbut-2-enoates

Russian Chemical Bulletin - New substituted 2-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-ylamino)-4-oxo-4-phenylbut-2-enoates were obtained by the reaction of...     

Reaction of 3-Cyano-2-diazo-4,5,6,7-tetrahydrobenzo[ b ]thiophene with 3-Imino-butyronitrile: Synthesis of Pyridazines,Thiophenes and Their Fused Derivatives

The reaction of the 3-cyano-2-diazo-4,5,6,7-tetrahydrobenzo[ b ]thiophene 1 with 3-imino-butyronitrile 2 gave the azo derivative ( 3 ). The reactivity of the latter product toward different reagents was studied to give fused derivatives with potential biological activities.     

Novel synthesis and antitumor evaluation of polyfunctionally substituted heterocyclic compounds derived from 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide

The reaction of 2-amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene with ethyl cyanoacetate gave 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide. The latter was used to synthesize different heterocyclic derivatives comprising thiophene, thiazole, pyrazole, pyridine, pyrimidine, and coumarin rings. The mechanistic and synthetic pathways depended on regioselective attack and/or cyclization by the cyanoacetamido moiety in the key precursor on various chemical reagents. The competition of the reaction pathways including dipolar cyclization, dinucleophilic-bielectrophilic attack, β-attack, Gewald-type attack, and condensation reactions led to the diversity of the synthesized products. The antitumor activities of the synthesized products were studied and evaluated. Most of the compounds revealed high inhibitory effects when screened in vitro for their antiproliferative activity. Three human cancer cell lines, namely, breast adenocarcinoma (MCF-7), non-small cell lung cancer (NCI-H460) and CNS cancer (SF-268) were used in the screening tests. The simplicity of the synthetic procedures which mainly involved one-pot reactions under mild reaction conditions, the convenience of yield production and the diversity of the reactive sites in the produced systems play a valuable role for further heterocyclic transformations and further biological investigations.     

A new method for the synthesis of novel 6-quinoxalinylpyrazolo[5,1-c][1,2,4]triazines

The reaction of the quinoxaline 1 with 4-ethoxycarbonyl-1H-pyrazole-5-diazonium chloride 7 at room temperature gave 3-[α-(4-ethoxycarbonyl-1H-pyrazol-5-ylhydrazono)methoxycarbonylmethyl]-2-oxo-1,2-dihydroquinoxaline 8. The pmr spectrum of 8 in deuteriodimethylsulfoxide supported the presence of two tautomers 8-I and 8-II. Refluxing of 8 in N,N-dimethylformamide or acetic acid resulted in cyclization to afford 8-ethoxycarbonyl-4-oxo-3-(3-oxo-3,4-dihydroquinoxalin-2-yl)-1,4-dihydropyrazolo[5,1-c][1,2,4]triazine 9. Compound 9 was also obtained directly by the reaction of 1 with 7 under reflux in better yield. The reaction of 9 with hydrazine hydrate provided the hydrazinium salt 10 , while the reactions of 9 with triethyl and trimethyl orthoformates in the presence of 1,8-diazabicyclo[5,4,0]-7-undecene produced 8-ethoxycarbonyl-4-ethoxyl-3-(3-oxo-3,4-dihydroquinoxalin-2-yl)pyrazolo[5,1-c][1,2,4]triazine 11a and 8-ethoxycarbonyl-4-methoxyl-3-(3-oxo-3,4-dihydroquinoxalin-2-yl)pyrazolo[5,1-c][1,2,4]triazine 11b , respectively. The chlorination of 11a with phosphoryl chloride gave 3-(3-chloroquinoxalin-2-yl)-8-ethoxycarbonyl-4-ethoxylpyrazolo[5,1-c]-[1,2,4]triazine 12 , whose reaction with morpholine afforded 8-ethoxycarbonyl-4-ethoxyl-3-[3-(morpholin-4-yl)-quinoxalin-2-yl]pyrazolo[5,1-c][1,2,4]triazine 13.     

Formation of derivatives of n-hydroxyindoles,annelated with furazan and furoxan rings

Upon reaction of 4-oxo-5-hydroxyimino-4,5,6,7-tetrahydrobenzofurazan and tetrahydrobenzofuroxan with acetylacetone, 8-acetyl-6-hydroxy-7-methylpyrrolo[2,3-e]benzofurazan and -benzofurazan-3-oxide are formed; and upon reaction with acetoacetate, 8-ethoxycarbonyl-6-hydroxy-7-methylpyrrolo[2,3-e]benzofurazan and -benzofurazan-3-oxide are formed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1676–1678, December, 1993.     

Synthesis of 5-Thioxo-hexahydrobenzo[b]thiopheno[2,3-d]-1,2,4-triazolo[1,5-c]pyrimidines and Related Compounds Based on Cyclocondensations of 2-Isothiocyanato-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene

5-Thioxo-4,6,8,9,10,11-hexahydro-benzo[b]thiopheno[2,3-d]-1,2,4-triazolo[1,5-c]pyrimidines and related compounds were prepared based on cyclizations of 2-isothiocyanato-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene with aminoketones and carboxylic hydrazides.     

Synthesis of 2-selenothieno[2,3-d]pyrimidine derivatives

Intramolecular cyclization of 2-(N-acylselenoureido)-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]thiophenes in alkaline media leads to the formation of the potassium salt (I) of 2-seleno-4-oxo-3,4,5,6,7,8-hexahydrobenzo[b]thieno[2,3-d]pyrimidine, acidification of which yielded the corresponding base in free form. Some pyrimidine compounds containing a selenium atom in the side chain were obtained by reaction of potassium salt I with halo derivatives (ClCH₂CH₂COOCH₃ and ClCH₂CH₂OH).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 753–754, June, 1977.     

Synthesis and biological evaluation of thiophene derivatives as acetylcholinesterase inhibitors

A series of new thiophene derivatives has been synthesized using the Gewald protocol. The acetylcholinesterase inhibition activity was assayed according to Ellman's method using donepezil as reference. Some of the compounds were found to be more potent inhibitors than the reference. 2-(2-(4-(4-Methoxyphenyl)piperazin-1-yl)acetamido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamide (IIId) showed 60% inhibition, compared to only 40% inhibition by donepezil.     

Design,Synthesis, and Antimicrobial Evaluation of Novel Thienopyrimidines and Triazolothienopyrimidines

2-Cyanoacetohydrazide and 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene derivatives were exploited as starting materials for the syntheses of novel thienopyrimidines and triazolothienopyrimidines. The proclivity of these compounds toward one-carbon donor reagents such as carbon disulfide, phenyl isothiocyanate, and aromatic aldehydes was investigated. The structures of all synthesized compounds were ascertained by spectral and analytical data. The antimicrobial activity of the target synthesized compounds was tested against various microorganisms.     

Beiträge zur Chemie schwefelhaltiger Heterocyclen, 3. Mitt.: Ringschlußreaktionen zu N-substituierten 2-Aminomethyl-Derivaten des 4-Oxo-3,4,5,6,7,8-hexahydro-benzo[b]thieno-[2,3-d]pyrimidins

Zusammenfassung Eine Gruppe von [2-Acylamino-4,5,6,7-tetrahydro-benzo[b]-thienyl-(3)]-carbonsäureamiden mit einem basischen Rest am Substituenten der 2-Stellung wurde nach zwei Methoden zu entsprechend substituierten 2-Alkyl-4-oxo-3,4,5,6,7,8-hexahydro-benzo[b]thieno[2,3-d]pyrimidinen cyclisiert. Die Herstellung der Ausgangsmaterialien erfolgte durch Umsetzung von [2-Chloracetylamino-4,5,6,7-tetrahydro-benzo[b]thienyl-(3)]-carbonsäureamid mit sekundären Aminen bzw. Benzylamin.

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A series of [2-acylamino-4,5,6,7-tetrahydro-benzo[b]thienyl-(3)]-carboxamides with a basic group in the substituent at position 2 was cyclized by two methods to the corresponding substituted 2-alkyl-4-oxo-3,4,5,6,7,8-hexahydro-benzo[b]thieno-[2,3-d]pyrimidines. The starting materials were prepared by reaction of [2-chloracetylamino-4,5,6,7-tetrahydro-benzo[b]-thienyl-(3)]-carboxamide with secondary amines or benzylamine.

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Mitt.:F. Sauter, Mh. Chem.99, 1591 (1968).     

Synthesis of 3-substituted-4-phenyl-2-thioxo-1,2,3,4,5,6,7,8-octahydrobenzo[4,5]thieno[2,3-á]pyrimidines

The reactions between 3-benzoyl-2-isothiocyanato-4,5,6,7-tetrahydrobenzo[b]thiophene and hydrazine or primary amines have been studied. The products obtained were identified as derivatives of 4-phenyl-2-thioxo-2,3,5,6,7,8-hexahydrobenzo[4,5]thieno[2,3-d]pyrimidine. Their easy reduction with sodium borohydride provided a useful method for the synthesis of 3-substituted-4-phenyl-2-thioxo-1,2,3,4,5,6,7,8-octahydrobenzo[4,5]thieno[2,3-d]pyrimidines. Both kind of compounds were evaluated as potential analgesic, anti-inflammatory and anti-arthritic agents.     

Design and synthesis of novel antimicrobial acyclic and heterocyclic dyes and their precursors for dyeing and/or textile finishing based on 2-N-acylamino-4,5,6,7-tetrahydro-benzo[b]thiophene systems

A series of novel polyfunctionalized acyclic and heterocyclic dye precursors and their respective azo (hydrazone) counterpart dyes and dye precursors based on conjugate enaminones and/or enaminonitrile moieties were synthesized. The dyes and their precursors are based on 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide, 2-ethoxycarbonyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide or 2-phenylcarbamoyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide systems as precursors. The latter compounds were used to synthesize polyfunctional thiophene-, thiazole-, pyrazole, pyridine-, pyrimidine-, oxazine-, as well as acyclic moieties. The dyes and dye precursors were characterized by elemental analysis and spectral methods. All dyes and their precursors were screened in vitro and evaluated for both their antibacterial and antifungal activities. MIC data of the novel dye systems and their respective precursors showed significant antimicrobial activity against most tested organisms. Some compounds exhibited comparable or even higher efficiency than selected standards. Dyes were applied at 5% depth for disperse dyeing of nylon, acetate and polyester fabrics. Their spectral characteristics and fastness properties were measured and evaluated.     

Synthesis of 3-hetaryl-4,5,6,7-tetrahydrobenzo[b]thiophenes

A novel efficient synthesis of 3-hetaryl-4,5,6,7-tetrahydrobenzo[b]thiophenes was achieved by the cyclocondensation of ethyl 2-amino-4,5,6,7-tetrahydrobenzo[6]thiophene-3-carboxylate with selected o-substituted aromatic amines or with alifatic, aromatic and heterocyclic acid hydrazides in the presence of polyphosphoric acid.