The chemistry of 1,2,5-thiadiazoles,IV. Benzo[1,2-c:3,4-c′:5,6-c″] tris [1,2,5] thiadiazole

Benzo [1,2-c:3,4-c′:5,6-c″] tris [1,2,5] thiadiazole (1) was synthesized from benzo [1,2-c:3,4-c′] - bis [1,2,5] thiadiazole (11) . Nitration of 11 gave compound 15 , which on direct amination gave nitroamine 17 . Reduction of 17 gave diamine 18 , and cyclization of 18 with thionyl chloride gave 1 . Diamine 18 was also cyclized with selenium oxychloride, glyoxal, 9,10-phenanthrene-quinone, and formic acid to give the compounds 4, 5, 19 , and 6 , respectively. A new procedure for the preparation of 2,1,3-benzothiadiazole (7) from o-phenylenediamine was used.     

Chemistry of isoindolines. The synthesis of 1,2,3,5,6,7-Hexahydrobenzo[1,2-c: 4,5-c′]dipyrrole and 1,2,3,4,5,6-Hexahydrobenzo[1,2-c: 3,4-c′]dipyrrole

The preparation and properties of 1,2,3,5,6,7-hexahydrobenzo[1,2-c: 4,5-c′]dipyrrole (I) and its isomer, 1,2,3,4,5,6-hexahydrobenzo[1,2-c:3,4-c′]dipyrrole (II), are described. Contrary to the claims of earlier investigators, compound I and its 2,6-diacetyl and 2,6-dicarboxarnide derivatives VI and IX are easily preparable, readily isolable, stable substances.     

A novel route from triptycenes to a dibenzo(Hafner's hydrocarbon), benz[a]indeno[1,2,3-cd]azulene

Triptycenes carrying a leaving group at one of the bridgehead carbons afforded the title compound in good to moderate yields when irradiated with a low-pressure Hg lamp. The tropylium ion and the strong CT-complexes of the hydrocarbon were prepared.     

Synthesis of substituted 1,4-diazepino[5,6,7-kl]acridines and imidazo[4,5,1-de][1,4]diazepino[5,6,7-mn]acridines

The synthesis of some substituted ll-methoxy-7-nitro-4H,8H-2,3-dihydro-1,4-diazepino[5,6,7-kl]acridines 4 with more diversified chains at position 4 is described. A convenient method for transformation of these compounds into the corresponding 4-substituted 12-methoxy-4H-2,3-dihydroimidazo[4,5,1-de][1,4]diazepino-[5,6,7-mn]acridine (5) is reported.     

1,2,3-benzotriazines. II. Reactions of benzimidazo[1,2-c][1,2,3]benzotriazines and naphth[1′,2′(2′,1′):4,5]imidazo[1,2-c][1,2,3]benzotriazine

A number of methyl- and halogeno-substituted benzimidazo[1,2-c][1,2,3]benzotriazines were subjected to a series of hydrolytic cleavages in acid media. The reactions of these compounds with dilute sulfuric acid yielded 2-(o-hydroxyphenyl)benzimidazoles. Concentrated hydrochloric acid produced a mixture of 2-(o-chlorophenyl)- and 2-(o-hydroxyphenyl)benzimidazoles. Hydrogen chloride in ethanol caused the formation of 2- phenylbenzimidazoles contaminated with small amounts of 2 - (o-chlorophenyl)benzimidazoles. The benzimidazo[1,2-c][1,2,3]benzotriazines underwent the Sandmeyer reaction to form 2-(o-chlorophenyl)- and 2-(o-bromophenyl)benzimidazoles in excellent yields. These reactions illustrated the behavior of these 1,2,3-triazines as internal diazonium compounds. Naphth[1′,2′(2′,1′):4,5]imidazo[1,2-c][1,2,3]benzotriazine behaved similarly. Bromination of some benzimidazo[1, 2 - c][1,2,3]benzotriazines in aqueous medium yielded bromine-substituted [1,2-c][1,2,3]benzotriazines.     

On the Purported Structure of Cyclodeca[1,2,3-de: 6,7,8-d′e′]dinaphthalene

The reaction of the bis(sulfonium salt) 7 in a solution of Na₂CO₃ in H₂O/EtOH yielded three main products 8 – 10 . The spectroscopic data of 8 were identical to those which led Mithcell and Sondheimer to assign them to cyclodeca[1,2,3-de: 6,7,8-d′e′]dinaphthalene ( 3 ). Our investigations show, however, that the correct structural assignment leads to the structure of 7,7a-dihydrodibenzo[de,mn]naphthacene ( 8 ).     

1,2,3-benzotriazines. I. The synthesis of some benzimidazo [1,2-c][1,2,3]-benzotriazines and naphth[1′,2,(2′,1′):4,5]imidazo[1,2-c][1,2,3]benzotriazine

A number of substituted benzimidazo[1, 2-c][1,2,3]benzotriazines were prepared by the diazotization of the appropriate 2-(o-aminophenyl)benzimidazoles. Diazotization of 2-(o-aminophenyl)naphth[1,2-d]imidazole yielded a new heterocyclic ring system. Various methods of preparation of 2 - (o-aminophenyl)benzimidazoles were investigated. The condensation of o-phenylenediamines with anthranilic acids, in the presence of polyphosphoric acid, provided a convenient route to 2-(o-aminophenyl)benzimidazoles but in several cases the products were contaminated with considerable amounts of 6-(o-aminophenyl)benzimidazo[1,2 -c]quinazolines. 2 - (o-Aminophenyl)benzimidazoles were also obtained by the catalytic hydrogenation of 2-(o-nitrophenyl)benzimidazoles which resulted from the condensation of an o-phenylenediamine with an o-nitrobenzaldehyde in ethanol, nitrobenzene or acetic acid. When the condensation was carried out in nitrobenzene, small amounts of 2-(o-aminophenyl)benzimidazoles were also formed. The Weidenhagen synthesis, which involves the reaction of an aromatic diamine with an aldehyde in the presence of copper acetate and subsequent decomposition of the cuprous salt of the benzimidazole, yielded 2-(o-aminophenyl)benzimidazoles instead of the expected 2-(o-nitrophenyl)benzimidazoles when the decomposition was carried out in ethanol. When the cuprous salt was treated with hydrogen sulfide in dilute hydrochloric acid, a mixture of amino- and nitrobenzimidazoles resulted. The ultraviolet and infrared spectra of all the compounds prepared were examined.     

Bis-aminoquinolines as potential antimalarial agents and a novel fused ring system,pyrano[3,2-c:5,6-c′]diquinoline

3,3′(1,3-Ethyliminodimethylene)bis(4-hydroxy-6-methoxy-2-methyl)quinoline ( 2c ) and related compounds were synthesized. 3,3-Methylenebis(4-hydroxy-6-methoxy-2-methyl)quinoline ( 5 ) was prepared and upon treatment with phosphorus oxychloride gave 1,13-dimethyl-5,9-dimethoxy-14H-pyrano[3,2-c:5,6-c′]diquinoIine (6), a novel ring system.     

Second-derivative constant-wavelength synchronous scan spectrofluorimetry for determination of benzo[b]fluoranthene, benzo[a]pyrene and indeno[1,2,3-cd]pyrene in drinking water

The use of derivative constant-wavelength synchronous scan fluorimetry is reported for the determination of three polycyclic aromatic hydrocarbon pollutants in drinking water (linearity range 0.4-4 mug 1(-1)). The limits of detection (LD) and quantification (LQ) (mug 1(-1)) are 0.01 and 0.07 for benzo[b]fluoranthene, 0.03 and 0.12 for benzo[a]pyrene and 0.19 and 0.57 for indeno[1,2,3-cd]pyrene in the presence of three other pollutants, benzo[k]fluoranthene, benzo[ghi]perylene and fluoranthene. The precision (RSD /= 85%) were satisfactory.     

Synthesis of diimidazo[1,2-a:2′,1′-c]pyrazines and diimidazo[1,2-a:2′,1′-c] [1,4]diazepines

Two new heterocyclic compounds, diimidazo[1,2-a:2′,1-c]pyrazine and 5H-diimidazo[1,2-a: 2,1′-c][1,4]diazepine have been synthesized by various routes from 2,2′-biimidazole (1) (2) together with some hydro, hydroxy and alkyl derivatives.     

Heptagon‐Embedded Pentacene: Synthesis,Structures, and Thin‐Film Transistors of Dibenzo[d,d′]benzo[1,2‐a:4,5‐a′]dicycloheptenes

This study presents a new class of conjugated polycyclic molecules that contain seven‐membered rings, detailing their synthesis, crystal structures and semiconductor properties. These molecules have a nearly flat C₆‐C₇‐C₆‐C₇‐C₆ polycyclic framework with a p‐quinodimethane core. With field‐effect mobilities of up to 0.76 cm² V⁻¹ s⁻¹ as measured from solution‐processed thin‐film transistors, these molecules are alternatives to the well‐studied pentacene analogues for applications in organic electronic devices.     

Synthesis of 4-methylfuro[3′,2′:5,6]benzofuro[3,2-c]pyridine

4-Methylfuro[3′,2′:5,6]benzofuro[3,2-c]pyridine ( 3 ) was synthetized from 2-acetylfuro[3,2-f]benzo[b]furan ( 4 ) or from 2-acetyl-5,6-dihydrofuro[3,2-f]benzo[b]furan ( 10 ). The key step involves a rearrangement-cyclization of azides 6 and 12 to form 4-methylfuro[3′,2′:5,6]benzofuro[3,2-c]pyridin-1(2H) one ( 7 ) and 8,9-dihydro-4-methylfuro[3′,2′:5,6]benzofuro[3,2c]pyridin-1(2H)-one ( 13 ). Introduction of an aminoalkyl chain on carbon 1 was effected by substitution of 1-chloro-4-methylfuro[3′,2′:5,6]benzofuro[3,2-c]pyridine ( 8 ).     

Synthesis of pyrido[3′,2′:4,5] thieno[3,2-d]pyrimidine derivatives

Pyrido [3′,2′:4,5]thieno[3,2-d] pyrimidine and several of its derivatives have been synthesized.