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.     

Application of directed metalation in synthesis. Part 8: Interesting example of chemoselectivity in the synthesis of thioaurones and hydroxy ketones and a novel anionic ortho-Fries rearrangement used as a tool in the synthesis of thienopyranones and thiafluorenones

Chemoselective synthesis of thioaurones or 3-hydroxy benzo[b]thiophen-2-aryl ketones, 1-hydroxy naphtho[2,1-b]thiophen-2-aryl ketones and chalcones from N,N-diethyl-ortho-methyl sulfanyl aryl amides were described. (Benzo[b]thiophen-2-yl) alkylates and (naphtho[2,1-b]thiophen-2-yl) alkylates undergo a novel anionic ortho-Fries rearrangement leading to (3-hydroxy benzo[b]thiophen-2-yl) and (1-hydroxy naphtho[2,1-b]thiophen-2-yl) alkyl ketones. The hydroxy ketones were used as intermediates in the synthesis of wide range of benzothienopyranones and thiafluorenones.     

The synthesis of novel polycyclic heterocyclic ring systems. 2. Naphmo[2,1-b:4,3-g]bisbenzo[b]thiophene

The novel polycyclic heterocyclic ring system, naphtho[2,1-b:4,3-g]bisbenzo[b]thiophene was synthesized from 5-[2-(2-bromo-3-thienyl)ethenyl]naphtho[2,1-b][1]benzothiophene. The assignment of its ¹H and ¹³C nmr spectra was also accomplished by utilizing two-dimensional nmr methods.     

Synthesis of anthra[b]thiophenes and benzo[b]naphtho[d]thiophenes

All isomers of the parent anthra[b]thiophenes and benzo[b]naphtho[d]thiophenes, namely anthra[2,3-b]thio-phene, anthra[2,1-b]thiophene, anthra[1,2-b]thiophene, benzo[b]naphtho[2,3-d]thiophene, benzo[b]naphtho[2,1-d]thiophene and benzo[b]naphtho[1,2-d]thiophene were synthesized using a new procedure.     

Enantioselective synthesis of (R) and (S)-[9,9′]bi[naphtho(2,1-b)furanyl]-8,8′-diol: a furo-fused BINOL derivative

The enantioselective synthesis of [9,9′]bi[naphtho(2,1-b)furanyl]-8,8′-diol, a modified BINOL, was achieved using an inexpensive route. Both enantiomers of [9,9′]bi[naphtho(2,1-b)furanyl]-8,8′-diol were obtained with satisfactory stereoselectivities by employing two optical antipodes of phenylethylamine as chiral influence in a Cu(II)Cl₂ catalyzed oxidative coupling step.     

Synthesis of 8-substituted naphtho[2,1-b]thiophenes with cationic side chains at position 4

A series of five 8-substituted α-[bis(2-hydroxyethyi)aminoethyl]naphtho[2,1-b]thiophenes 7 and a series of seven N-(3-dimethylaminopropyl)-8-substituted naphtho[2,1-b]thiophene-4-carboxamides 8 have been synthesized. The naphtho[2,1-b]thiophene-4-carboxylic acids 4 were prepared by photooxidative cyclization of α-(2-thienyi)-β-arylacrylic acids 3. The carboxylic acids 4 were converted by a conventional five step route involving α-bromoketone intermediates to the a-[bis(2-hydroxyethyl)aminomethyl]-8-substituted naphtho-[2,1-6]thiophene-4-methanols 7 and by a standard two-step amide preparation to the N-(3-dimethylaminopropyl)-8-substituted naphtho[2,1-6]thiophene-4-carboxamides 8 .     

Synthesis of novel benzo naphtho naphthyridines from 2,4-dicloroquinolines

A schematic study on the condensation of 2,4-dichloroquinolines ( 1 ) with 1-naphthyamine ( 2 ) in the presence of CuI as a catalyst to functionalized mono ( 3 ) and di ( 4 ) substituted naphthylamino quinolines was described. Consequently, these mono- and di-substituted amines on polyphosphoric acid-catalyzed cyclization reaction with p-toluic acid and acetic acid to yield the linear benzo[b]naphtho[2,1-g][1,8]naphthyridines ( 5 ) and angular benzo[b]naphtho[2,1-h] naphthyridines ( 6 ) in good yields. In addition to descried the similar synthesis of benzo[g]naphtho [2,1-b][1,8]naphthyridines ( 12 ) and benzo[h]naphtho[2,1-g][1,8]naphthyridines ( 13 ) from 2,4-dichlorobenzo[h]quinoline ( 8 ) with various anilines ( 9 ) through my intermediates ( 10 and 11 ).     

Cascade cyclization of aryldiynes using iodine: synthesis of iodo-substituted benzo[b]naphtho[2,1-d]thiophene derivatives for dye-sensitized solar cells

A facile, efficient, and general synthetic method for iodo-substituted benzo[b]naphtho[2,1-d]thiophenes has been developed via a cascade cyclization of thioanisole-substituted aryldiynes using iodine. A new donor–π linker–acceptor (D–π–A) organic dye, G1, with the benzo[b]naphtho[2,1-d]thiophene moiety as an electron donor has been synthesized, and the performance of dye-sensitized solar cell based on G1 has been investigated.     

Microwave-assisted Claisen rearrangement of naphthyl 2-propynyl ethers: synthesis of naphthofurans

An efficient two-step approach for the synthesis of naphtho[1,2-b]furans and naphtho[2,1-b]furans has been developed. Various functionalized propargyl alcohols were etherified with α- or β-naphthol under Mitsunobu reaction conditions to give naphthyl 2-propynyl ethers, which underwent a facile microwave-assisted Claisen rearrangement and concomitant anionic cyclization to yield naphthofuran derivatives under basic reaction conditions.     

Synthesis of N(3-dimethylaminopropyl)-6-substituted naphtho[2,1-b]thiophene-4-carboxamides

A series of N-(3-dimethylaminopropyl)-6-substituted naphtho[2,1-b]thiophenes-4-carboxamides have been synthesized. 6-Substituted naphtho[2,1-b]thiophene-4-carboxylic acids were obtained upon oxidative-photo-cyclization of α-(2-thienyl)-β-arylacrylic acids. The naphtho[2,1-b]thiophene carboxylic acids were converted to the corresponding amides through their acid chlorides or, in one case, by use of 1,1-carbonyldiimidazole coupling of the amine and the acid.     

Synthesis and properties of naphthobisbenzo[b]thiophenes: structural curvature of higher acene frameworks for solubility enhancement and high-order orientation in crystalline states

The syntheses of naphtho[2,3-b:7,6-b′]- and naphtho[2,1-b:5,6-b′]bisbenzo[b]thiophenes (NBBTs) are achieved via inter- and intramolecular stepwise Friedel–Crafts-type reactions. The structural curvature of these NBBTs are found to improve their solubility in organic solvents, and to form well-defined herringbone structures in single crystals, especially when the C_2v symmetrical naphtho[2,3-b:7,6-b′]bisbenzo[b]thiophene takes the form of asymmetric space groups in a parallel direction with each other, and having exhibited OFET characteristics with a hole mobility of 7 × 10^?5 cm² V^?1 s^?1.     

The synthesis of the monomethyl isomers of benzo[b]naphth[2,1-d]thiophene

All isomers of the monomethylbenzo[b]naphth[2,1-d]thiophenes were synthesized using photocyclization of 3-styrylbenzo[b]thiophenes. The 1-, 3-, 4-, and 5-methylbenzo[b]naphtho[2,1-d]thiophenes were synthesized by irradiation of the corresponding methylated 3-styrylbenzo[b]thiophenes which were prepared by the Wadsworth-Emmons reaction of diethyl benzo[b]thenylphosphonate with o-, m-, p-tolualdehyde and acetophenone. The 7-, 8-, 9- and 10-methylbenzo[b]naphtho[2,1-d]thiophenes were synthesized by decarboxylation of 7-, 8-, 9- and 10-methylbenzo[b]naphtho[2,1-d]thiophene-6-carboxylic acid with copper in quinoline. These carboxylic acids were prepared by photocyclization of the corresponding 2-(benzo[b]thiophen-3-yl)-3-phenylpropenoic acids which were prepared by the condensation of the methylated benzo[b]thiophene-3-ylacetic acids with benzaldehyde in the presence of triethylamine in acetic anhydride.     

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.     

Carbenoid induced irreversible ring opening of naphthopyrans

Contrary to expectation rhodium carbenoids do not undergo cycloaddition to the 2H-pyran unit of the isomeric naphthopyrans 3 and 5. With 3, a naphtho[2,1-b]pyran-8-ylacetate, 4 is formed and a novel merocyanine dye 6 results from a cycloaddition across the C-5-C-6 double bond of the naphtho[1,2-b]pyran 5. Tethering the carbenoid to the naphtho[1,2-b]pyran system 5, as in 10, results in a similar mode of addition and affords the intensely coloured tetracycle 11.     

An efficient synthesis of 4,5-dihydronaphtho[2,1-b]furan through a novel ring transformation of 2H-pyran-2-one

An innovative route for the synthesis of substituted naphtho[2,1-b]furan has been delineated through a ring transformation reaction of suitably functionalized 2H-pyran-2-ones by reaction with 6,7-dihydro-5H-benzofuran-4-one, in good yield.     

Photocyclization of 2-(naphth-1-yl)-3-(thien-2-yl)propenoic acid and the total assignment of the 1H- and 13C-NMR spectra of the product

Photocyclization of the substituted 2-(naphth-1-yl)-3-(thien-2-yl)propenoic acid ( 3 ) in the presence of iodine and air in a benzene-cyclohexane mixture afforded a separable mixture of three compounds, phenanthro[2,1-b]thiophene-10-carboxylic acid ( 4 ), phenanthro[2,1-b]thiothene ( 5 ), and naphtho[1,8-cde]-thieno[3,2-g][2]benzopyran ( 6 )     

Photocyclization of 2-[1]benzothien-3-yl)-3-phenylpropenoic acids

Photocyclization of the substituted 2-([1]benzothien-3-yl)-3-phenylpropenoic acids 3a-c in the presence of iodine and air in a benzene-cyclohexane mixture afforded a separable mixture of three compounds, benzo[b]naphtho[2,1-d]thiophene-6-carboxylic acids 4a-c , 6H-benzo[b]naphtho[2,3-d]thiopyran-6-ones 5a-c , and 10-methoxy-2-methyl-6H-benzo[b]naphtho[2,3-d]pyran-6-one ( 6 ).     

From N,N-diphenyl-N-naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl-amine to propeller-shaped N,N,N-tri(naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl)-amine: syntheses and structures

Three unique propeller-shaped helicenyl amines compounds: N,N-diphenyl-N-naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl-amine (1), N-phenyl-N,N-di(naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl)amine (2), and N,N,N-tri(naphtho[2,1-b]thieno[2,3-b:3′,2′-d]dithiophene-5-yl)amine (3) were efficiently synthesized by Wittig reaction and oxidative photocyclization. The crystal structures of 1, 2 and molecular configuration optimization (DFT-B3LYP/6-31+G(d)) of 3 reveal that the steric hindrance from the moiety of trithia[5]helicene effectively forces the nitrogen atom and the three bonded carbon atoms to coplanar and the interplanar angles of the facing terminal thiophene ring and benzene ring becoming larger when the helical arm increased from 1 to 3. Electrochemical properties and UV–vis absorption behaviors of 1, 2, 3 were primarily determined by the moiety of trithia[5]helicene.     

A new approach for the synthesis of some pyrazolo[5,1‐c]triazines and pyrazolo[1,5‐a]pyrimidines containing naphtofuran moiety

Naphtho[2,1‐b]furan‐2‐yl)(8‐phenylpyrazolo[5,1‐c][1,2,4]triazin‐3‐yl)methanone, ([1,2,4]triazolo[3,4‐c][1,2,4]triazin‐6‐yl)(naphtho[2,1‐b]furan‐2‐yl)methanone, benzo[4,5]imidazo[2,1‐c][1,2,4]triazin‐3‐yl‐naphtho[2,1‐b]furan‐2‐yl‐methanone, 5‐(naphtho[2,1‐b]furan‐2‐yl)pyrazolo[1,5‐a]pyrimidine, 7‐(naphtho[2,1‐b]furan‐2‐yl)‐[1,2,4]triazolo[4,3‐a]pyrimidine, 2‐naphtho[2,1‐b]furan‐2‐yl‐benzo[4,5]imidazo[1,2‐a]pyrimidine, pyridine, and pyrazole derivatives are synthesized from sodium salt of 5‐hydroxy‐1‐naphtho[2,1‐b]furan‐2‐ylpropenone and various reagents. The newly synthesized compounds were elucidated by elemental analysis, spectral data, chemical transformation, and alternative synthetic route whenever possible. J. Heterocyclic Chem., (2012).     

Quinoxalines. Part 13: Synthesis and mass spectrometric study of aryloxymethylquinoxalines and benzo[b]furylquinoxalines

A series of new aryloxymethylquinoxalines, benzo[b]- and naphtho[2,1-b]furylquinoxalines, possessing potential biological activity, was prepared, characterized by IR and NMR spectroscopy and their electron ionization (EI) mass spectra studied in detail. The aryloxymethylquinoxalines were obtained by reacting halogenomethylquinoxalines with bifunctional O-nucleophiles. The benzo[b]furylquinoxalines and naphtho[2,1-b]furylquinoxalines were prepared via two routes, which differed in the order of the two cyclization steps involved in the syntheses. The composition of the ions obtained by EI mass spectrometry were determined by accurate mass measurements and the fragmentation pathways clarified by B/E linked scans and collision induced dissociation. The mass spectrometric behaviour of the compounds studied as to the possible loss of OH radicals proved to be very characteristic.