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.     

K-region oxides and imines of benzo[b]phenanthro[2,3-d]thiophene and benzo[b]phenanthro[3,2-d]thiophene

The syntheses of the K-oxides and K-imine derivatives of benzo[b]phenanthro[2,3-d]thiophene and benzo-[b]phenanthro[3,2-d]thiophene are described. The parent hydrocarbons 1 and 2 were oxidized with osmium tetroxide and sodium metaperiodate, and the dialdehydes 12 and 18 so formed, cyclized to the corresponding epoxides 1a,12b-dihydrobenz[b]oxireno[9,10]phenanthro[2,3-d]thiophene ( 7 ) and 1a,12b-dihydrobenz-[b]oxireno[9,10]phenanthro[3,2-d]thiophene ( 13 ). Reaction of the oxiranes with sodium azide gave mixtures of azido-alcohols that, in turn, were transformed to the thiaarene imines 1a,12b-dihydro-1H-benz[b]azirino-[9,10]phenanthro[2,3-d]thiophene ( 8 ) and 1a,12b-dihydro-1H-benz[b]azirino[9,10]phenanthro[3,2-d]thiophene ( 14 ), respectively, with the aid of tri-n-butylphosphine.     

Uses of 2‐diazo‐4,5,6,7‐tetrahydrobenzo[b]thiophene derivatives in the synthesis of azoles,azines, and their fused derivatives

The reactions of 2‐diazo‐4,5,6,7‐tetrahydrobenzo[b]thiophene derivatives with dimeric adducts 2a and 2b gave the hydrazone derivatives 3a and 3b , respectively. The reactivity of the latter products towards various chemical reagents was studied in order to provide azole and azine derivatives incorporating the thiophene ring, and most of them showed high antimicrobial activity. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:108–115, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10003     

Benzo[b]thiophene derivatives. XXV. Condensation and reductive alkylation of 3-aminoalkylbenzo[b]thiophenes with formaldehyde

The reductive alkylation of 3-aminomethylbenzo[b]thiophene by the Eschweiler-Clarke (formaldehyde-formic acid) method and of 3-β-aminoethylbenzo[b]thiophene by the Borch (formaldehyde-cyanoborohydride) method proceeded in good yields. However, the Eschweiler-Clarke reaction with 3-β-aminoethylbenzo[b]thiophene gave the Pictet-Spengler cyclized product, N-methyl-1,2,3,4-tetrahydrobenzo[b]thieno[2,3c]pyridine. Mechanistic aspects of the latter reaction were investigated.     

Synthesis of benzo[b]phenanthro[d]thiophenes

The synthesis of benzo[b]phenanthro[1,2-d]thiphene ( 1 ), benzo[b]phenanthro[4,3-d]thiophene ( 2 ), benzo-[b]phenanthro[2,1-d]thiophene ( 3 ) and benzo[b]phenanthro[3,4-d]thiophene ( 4 ) from appropriately substituted olefines by photochemical cyclodehydrogenation is described. The photolysis of olefin 9 gave a mixture of 4 and anthra[1,2-b]benzo[d]thiophene ( 5 ).     

Synthesis of phenaleno[1,9-bc]thiophene

The cyclization of 2-acetonylthionaphthalene, prepared from 2-mercaptonaphthalene (1) and chloro-acetone in the presence of sodium hydroxide, with polyphosphoric acid gave 1-methylnaphtho[2,1-b]thiophene (4) in 64% overall yield from 1. By bromination with N-bromosuccinimide, 4 was converted in 40% yield into l-bromomethylnaphtho[2,1-b]thiophene (8) . Treatment of 8 with potassium cyanide in a phase-transfer medium gave l-cyanomethylnaphtho[2,1-b]thiophene (10) in good yield. Compound 10 was reduced to the corresponding aldehyde 11 and then cyclized with polyphosphoric acid to phenaleno[l,9-bc]thiophene (12) in 24% overall yield from 10.     

N-Substituierte 2-Methyl-3-aminoacetyl-benzo[b]thiophene und 2-Methyl-3-(α-hydroxy-β-amino-äthyl)-benzo[b]thiophene

Zusammenfassung Bromierung von 2-Methyl-3-acetyl-benzo[b]thiophen ergab 2-Methyl-3-bromacetyl-benzo[b]thiophen, das beim Umsetzen mit Dimethylamin, Morpholin und N-Methylpiperazin die entsprechend basisch substituierten 3-Acetylverbindungen lieferte. Diese wurden mit LiAlH₄ zu den -Hydroxyverbindungen reduziert.In ähnlicher Weise wurde auch 3-Diäthylaminoacetyl-benzo[b]thiophen dargestellt.

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Bromination of 2-methyl-3-acetyl-benzo[b]thiophene gave 2-methyl-3-bromacetyl-benzo[b]thiophene, which reacted with dimethylamine, morpholine and N-methylpiperazine to give the corresponding base-substituted 3-acetyl derivatives. These were reduced by LiAlH₄ to the -hydroxy compounds.Similarily 3-diethylaminoacetyl-benzo[b]thiophene was synthesized.

     

The insertion and extrusion of heterosulfur bridges. XV. S-bridging of 2,2′-binaphthyl and 1-(2-naphthyl)cyclohexene. Studies on hydrodehalogenation during the reaction

Regioselectivity occurs in the sulfur-bridging reactions of 2,2′-binaphthyl (1) and 1-(2-naphthyl)cyclohexene (7) by means of hydrogen sulfide and a chromia-alumina-magnesia catalyst (designated I) in a flow apparatus at 550°. Thus, 1 gives a higher yield (6.1%) of dinaphtho[1,2–6:2′,l'-d]thiophene from 1,1′-bridging than of dinaphtho[1,2-b:2′,3′-d]thiophene (3.4%) from l,3′-bridging. No product expected from 3,3′-bridging was identified. Substrate 7 undergoes both dehydrogenation and bridging to yield 2-phenylnaphthalene (8%), benzo[b]naphtho[2,1-d]thiophene (9%) from alpha bridging, and benzo[b]naphtho[2,3-d]thiophene (3%) from beta bridging into the naphthalene ring. Exploratory studies showed that either sulfided catalyst I or a sulfided molybdenum( VI ) oxide-alumina-cobalt( II ) oxide catalyst ( II ) effects hydrodehalogenation of various monohalo- and polyhaloarenes (where halo, X, is chloro or bromo) at 450–550°. In the biphenyl, phenanthrene, naphthalene, and pyrene systems, halogen was lost either under sulfur-bridging conditions or under hydrogenolysis conditions, i.e. with methanol as a reactant. For every substrate the parent arene was isolated or identified as a reaction product. In selected experiments, acid HX was also identified in the effluent. Use of hydrogen sulfide as a reactant led to formation of dibenzothiophene and phenanthro[4,5-bcd]thiophene as main products in the biphenyl and phenanthrene systems, respectively; while use of methanol as a reactant gave small amounts of methyl bromide (for X = Br) and methylarenes.     

The synthesis of benzo[b]phenanthro[d]thiophenes and anthra[b]benzo[d]thiophenes

The synthesis of benzo[b]phenanthro[2, 3-d]thiophene ( 5 ), benzo[b]phenanthro[4, 3-d]thiophene ( 6 ), benzo-[b]phenanthro[2, 1-d]thiophene ( 9 ), benzo[b]phenanthro[3, 2-d]thiophene ( 14a ), anthra[1, 2-b]benzo[d]thiophene ( 24 ), anthra[2, 3-b]benzo[d]thiophene ( 29 ) and anthra[2, 1-b]benzo[d]thiophene ( 30 ) is described as well as the preparation of 13-methylbenzo[b]phenanthro[3, 2-d]thiophene ( 14b ).     

Etude de la décomposition thermique d'azido dithiényl-1,2 éthènes et éthanes

Thermal decomposition of azido-1,2-dithienylethenes 1 gave thienyl 4H-thieno[3,2-b]pyrroles 3 . For the 3,4-disubstituted thiophene derivatives 2 , the same reaction led to the amino-1,2-dithienylethenes 4 . In contrast, only azido-1,2-dithienylethanes 7 led to thienyl-5,6-dihydro-4H-thieno[3,4-b]pyrroles 8 . The structure of the obtained derivatives was established on the basis of ¹H nmr, ir, and mass spectral data.     

Photochemical synthesis of heteroatom-containing polycyclic aromatic compounds

Anthra[2,1-b]furan, anthra[2,1-b]benzo[d]furan, anthra[2,1-b]thiophene, anthra[1,2-b]thiophene, anthra[2,1-b]benzo[d]thiophene, anthra[2,1-b]pyrrole and naphtho[2,3-c]carbazole derivatives were synthesized in fairly good yields by a one-pot photocycloaddition reaction of 2,3-disubstituted 1,4-naphthoquinone with 1,1-diarylethylene. This is the first reported synthesis of these aromatic compounds.     

Angular polycyclic thiophenes containing two thiophene rings. Part II

The syntheses of naphtho[1,2–6:7,6-b′]bisbenzo[b]thiophene ( 4 ), naphtho[1,2–6:7,8-b′]bisbenzo[b]thiophene ( 5 ), naphtho[2,1-b:7,6-b′]bisbenzo[b]thiophene ( 8 ), naphtho[2,1-b:7,8-b′]bisbenzo[b]thiophene ( 9 ), naphtho-[1,2–6:5,6-b′]bisbenzo[b]thiophene ( 14 ), naphtho[1,2–6:6,5-b]bisbenzo[b]thiophene ( 17 ) and naphtho[2,1–6:-6,5-b′]bisbenzo[b]thiophene ( 23 ) are reported.     

Synthesis of new functionalized imidazo[2,1‐b]thiazoles and thiazolo[3,2‐a]pyrimidines

5‐Oxo‐5H‐[1,3]thiazolo[3,2‐a]pyrimidine‐6‐carboxylic acid ( 4 ), and 6‐methylimidazo[2,1‐b]thiazole‐5‐carboxylic acid ( 17 ) were reacted with amines 6a‐i by the reaction with oxalyl chloride and N, N‐di methyl‐formamide as a catalyst into primary and secondary amide derivatives 7‐14 and 19‐22. From compound 24 N,N'‐disubstituted ureas 26, 27 and perhydroimidazo[1,5‐c]thiazole 29 derivatives of imidazo[2,1‐b]thiazole were prepared. By nmr analysis of compound 29 , the existence of two stereoisomers resulting from both optical, due to centre of chirality at C7′a, and conformational isomerism, due to restricted C5? N6′ bond rotation were proved.     

Study of the reactivity of ketone enolates with 3-halo-2-amino derivatives of benzo[b]thiophene under photostimulated sRN1 reaction conditions

Reactivity of the 3-halo-2-amino derivatives of benzo[6]thiophene 1a-c and 2 with several ketone enolates 3–5 have been studied under photostimulated S_RN1 reaction conditions. The normal substitution product 6 only was obtained in low yields using potassioacetophenone 3 as the enolate ion and 2-(tert-butoxycarbonylamino)-3-chlorobenzo[b]thiophene ( 1a ) and 2-(tert-butoxycarbonylamino)-3-iodobenzo[b]thiophene ( 1c ) as substrates. In all reactions the main product was the corresponding dehalogenated substrate 7a-b , thus indicating that reduction of the substrate strongly competes with the desired substitution reaction.     

Angular polycyclic thiophenes containing two thiophene rings. I

We describe the synthesis of thieno[2,3-c]dibenzothiophene ( 6 ), thieno[3,2-c]dibenzothiophene ( 10 ), thieno-[3,2-a]dibenzothiophene ( 14 ), thieno[2,3-a]dibenzothiophene ( 16 ), benzo[1,2-b:4,3-b]bisbenzo[b]thiophene ( 18 ), benzo[1,2--6:3,4-b]bisbenzo[b]thiophene ( 20 ), benzo[2,1--6:3,4-b]bisbenzo[b]thiophene ( 22 ), benzo[1,2-b:3,4-g]bisbenzo[b]thiophene ( 27 ), benzo[1,2-b:4,3-e]bisbenzo[b]thiophene ( 29 ), benzo[2,1--6:3,4-g]bisbenzo[b]thiophene ( 36 ), benzo[2,1--6:4,3-e]bisbenzo[b]thiophene ( 38 ), benzo[1,2--6:4,3-g]bisbenzo[b]thiophene ( 41 ), benzo[1,2-b:4,5-g]bisbenzo[b]thiophene ( 42 ), benzo[1,2-b:3,4-e]bisbenzo[b]thiophene ( 44 ) and benzo-[1,2-b:5,4-e]bisbenzo[b]thiophene ( 45 ).     

Beiträge zur Chemie schwefelhaltiger Heterocyclen, 4. Mitt.: 6H-Benz[b]indeno[1,2-d]thiophen und 10H-Benz[b]indeno-[2,1-d]thiophen

Zusammenfassung Intramolekulare Cyclisierungsreaktionen von 3-Phenyl-benzo[b]thiophen-2-carbonsäurechlorid und von 2-Phenyl-benzo[b]thiophen-3-carbonsäurechlorid lieferten 6-Oxo-6H-benz[b]indeno[1,2-d]thiophen bzw. 10-Oxo-10H-benz[b]indeno[2,1-d]thiophen.

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Contributions to the chemistry of sulfur containing heterocycles, IV.: 6H-Benzo[b]indeno[1,2-d]thiophene and 10H-benzo-[b]indeno[1,2-d]thiophene

Intramolecular cyclization reactions of 3-phenyl-benzo[b]thiophene-2-carbonyl chloride and of 2-phenyl-benzo[b]-thiophene-3-carbonyl chloride gave 6-oxo-6H-benz[b]indeno-[1,2-d]thiophene and 10-oxo-10H-benz[b]indeno[2,1-d]thiophene, respectively.

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3. Mitt.:F. Sauter, Mh. Chem.99, 2100 (1968).     

Synthesis of new 4-quinolone-type compounds in the benzo[b]thiophene series

Some new derivatives of 1,4-dihydro-4-oxo-3-pyridinecarboxylic acid (quinolone-type compounds) 5 and 13 have been prepared in the benzo[b]thiophene series. The key step was the construction of the pyridine ring starting from 2-aminobenzo[b]thiophene derivatives. The synthesis of amine 9 , was performed by using an original “animation” reaction.     

A concise synthesis and electrochemical behavior of functionalized poly(thieno[3,4-b]thiophenes): New conjugated polymers with low bandgap

New thieno[3,4-b]thiophene derivatives were prepared via a short and versatile synthetic route. Electrochemical studies of 2-heptenylthieno[3,4-b]thiophene, 2-styrylthieno[3,4-b]thiophene, and 2-phenyl-3-(thieno[3,4-b]thiophene-2-yl)acrylonitrile and the corresponding polymers revealed that raising the HOMO and lowering the LUMO can be attained by functionalizing thieno[3,4-b]thiophene with aromatic resonance-enhancing and electron-withdrawing groups. The bandgap of resulting polymers varied from 0.78 to 1.0 eV, indicating that poly(2-phenyl-3-(thieno[3,4-b]thiophene-2-yl)acrylonitrile) is one of the lowest bandgap polymers ever reported.     

Chemistry of new dimethyl-benzo,-1,3,6-oxadiazepine and 1,3,5-triazepine derivatives as anticancer agents

A series of novel substituted 2,4-dimethyl-benzo[f][1,3,5] triazepine, such as 2-thioxopyrimidinone(4), 2-oxopyridine-3-carbonitrile(6), benzamide(8), N’-(6-oxopyrimidine)benzohydrazide(10), 1-(4-(1,3,4-oxadiazole)thiophene)ethan-one(12), 1-(4-methylthiophene-3-carbonyl)pyrazolidine-dione(14), 1-(4-(pyrazole-carbonyl)-3-methylthiophene)ethanone(16), ethyl dimethylthieno[2,3-b]pyridine-2-carboxylate (18), and 2-thioxo-thieno[2,3-d]pyrimidinone(20) derivatives, were synthesized from 2,4-dimethyl benzo[d] [1,3,6] oxadiazepine (2). The structures of these newly synthesized compounds were established on the basis of their spectral data and elemental analysis. These compounds were also screened for their anti-tumor activities. Some of the prepared compounds showed promising activities for example; benzotriazepine, thienopyrimidine, oxadiazole, and thiophene moiety displayed cytotoxic activity.     

1,3-Dipolar cycloaddition reactions of benzo[b]thiophene 1,1-dioxide with azomethine ylides

New pyrrolo derivatives of benzo[b]thiophene 1,1-dioxide have been synthesised via 1,3-dipolar cycloaddition reactions. Reaction of benzo[b]thiophene 1,1-dioxide with stabilised azomethine ylides gave products in low yield but high stereoselectivity whereas reaction with non-stabilised azomethine ylides gave high overall yields but low stereoselectivity.