Nitration studies of naphtho[2,3-c][1,2,5]thiadiazole

Nitration of naphtho[2,3-c][1,2,5]thiadiazole gives the 5-nitro derivative in 61–66% yield. Chlorination of this product apparently gives an unstable addition product which loses hydrogen chloride on recrystallization to give 4-chloro-8-nitronaphtho[2,3-c][1,2,5]thiadiazole. Thus, naphtho[2,3-c][1,2,5]thiadiazole under nitrating conditions behaves as a 2-substituted naphthalene rather than as an anthracene analog.     

Donor-acceptor conjugated polymer based on naphtho[1,2-c:5,6-c]bis[1,2,5]thiadiazole for high-performance polymer solar cells

Donor-acceptor conjugated polymers PBDT-DTBT and PBDT-DTNT, based on 2,1,3-benzothiadiazole (BT) and naphtho[1,2-c:5,6-c]bis[1,2,5]thiadiazole (NT), have been designed and synthesized for polymer solar cells. NT contains two fused 1,2,5-thiadiazole rings that lower the band gap, enhance the interchain packing, and improve the charge mobility of the resulting polymer. Consequently, the NT-based polymer PBDT-DTNT exhibited considerably better photovoltaic performance with a power conversion efficiency (PCE) of 6.00% when compared with the BT-based polymer PBDT-DTBT, which gave a PCE of 2.11% under identical device configurations.     

Efficient Red Electroluminescence From Phenanthro[9,10-d]imidazole-Naphtho[2,3-c][1,2,5]thiadiazole Donor-Acceptor Derivatives

Red emission is one of the three primary colors and is indispensable for full color displays. Fluorescent materials that can generate efficient red electroluminescence (EL) are limited and need to be developed. In this work, we report efficient red emitters based on phenanthro[9,10-d]imidazole-naphtho[2,3-c][1,2,5]thiadiazole donor-acceptor derivatives. The molecules, abbreviated as PINzP and PINzPCN, exhibited high photoluminescence quantum yield (PLQY) up to unity in doped films. They can also reach a relatively high PLQY of ∼30% in neat films. PINzP and PINzPCN were capable of generating efficient red EL in doped devices with a maximum external quantum efficiency (EQE) of 6.96% and 5.92%, respectively.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 8 . [1]Benzothieno[2,3-c]naphtho[1,2-h]quinoline and [1]benzothieno[2,3-c]naphtho[1,2-h][1,2,4]triazolo[4,3-a]quinoline

The previously unknown polycyclic heterocyclic ring systems, namely, [1]benzothieno[2,3-c]naphtho[1,2-h]-quinoline and [1]benzothieno[2,3-c]naphtho[1,2-h][1,2,4]triazolo[4,3-a]quinoline were synthesized via photocyclization of 3-chloro-N-(1′-phenanthryl)benzo[b]thiophene-2-carboxamide.     

Synthesis and structures of 5(3H)-oxotetrahydro-1H-imidazo[4,5-c][1,2,5]thiadiazole 2,2-dioxides

The reactions of sulfamides with 4,5-dihydroxyimidazolidin-2-ones were studied at ambient and high pressure. The previously unknown derivatives of 5(3H)-oxotetrahydro-1H-imidazo-[4,5-c][1,2,5]thiadiazole 2,2-dioxide, viz., sulfo analogs of tetrahydroimidazo[4,5-d]imidazole-2,5-(1H,3H) diones (glycolurils), were synthesized. The structures of some of these compounds were established by X-ray diffraction. The high-pressure reactions performed under conditions of solvent phase transitions afforded also N-(1,3-diethyl-5-hydroxy-2-oxoimidazolidin-4-yl)-N,N′-dialkylsulfamides. Among these compounds, a new conglomerate was found. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1711–1719, May, 2008.     

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.     

Synthesis of novel imidazo[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines and pyrimido[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines

Several 1 1-amino-5H-pyrrolo[2,1-c][1,4]benzodiazepines have been used as starting material to prepare a number of derivatives of 9H-imidazo[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines and 10H-pyrimido[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines. The imidazole nucleus was built by reaction of amidines with ethyl bromopyruvate or aminoacetaldehyde dimethylacetal. Several derivatives of imidazo[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepine have been prepared by formylation of the pyrrole ring followed by formation of thioamides. Condensation of 11-amino-5H-pyrrolo[2,1-c][1,4]benzodiazepines with diethyl ethoxymethylenemalonate afforded intermediate diesters which were transformed into the corresponding 10H-pyrimido[1,2-a]pyrrolo[2,1-c]-benzodiazepines.     

A new derivative of 1,5-dihydropyrazolo[4,3-c][1,2,5]benzotriazepine

A new compound, 1,5-dihydro-3-methyl-7-nitro-propylpyrazolo[4,3-c][1,2,5]benzotriazepine, was synthesized by intramolecular cyclization of 5-amino-4-[(2-bromo-5-nitrophenyl) azo]-3-methyl-1-isopropylpyrazole, and it was established on the basis of the spectral data that the triazepine ring in the synthesized compound exists in two tautomeric forms — amino-azo- and hydrazone. The structure of the compound synthesized was confirmed by the data of the PMR, IR, electronic, and mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1136–1139, August, 1984.     

1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl: a long-lived radical anion and its stable salts

[1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazole (1) is synthesized in 62% yield by fluoride ion-induced condensation of 3,4-difluoro-1,2,5-thiadiazole with (Me(3)SiN=)(2)S. The reversible electrochemical reduction of 1 leads to the long-lived [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazolidyl radical anion (2) and further to the dianion (3). The radical anion 2 is also obtained by the chemical reduction of the precursor 1 with t-BuOK in MeCN. The radical anion 2 is characterized by ESR spectroscopy in solution and in the crystalline state. The stable salts [K(18-crown-6)][2] and [K(18-crown-6)][2].MeCN (8 and 9, respectively) are isolated from the spontaneous decomposition of the [K(18-crown-6)][PhXNSN] (6, X = S; 7, X = Se) salts in MeCN solution followed by XRD characterization. The radical anion 2 acts as a bridging ligand in 8 and as chelating ligand in 9. The structural changes observed by XRD in going from 1 to 2 are explained by means of DFT/(U)B3LYP/6-311+G calculations.     

Synthesis of low band gap [1,2,5]-thiadiazolo[3,4-g]quinoxaline and pyrazino[2,3-g]quinoxaline derivatives by selective reduction of benzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole

The reduction of a dithienylbenzobisthiadiazole derivative TBBT can be performed selectively so as to afford either [1,2,5]-thiadiazolo[3,4-g]quinoxaline (TQ) or pyrazino[2,3-g]quinoxaline (PQ) derivatives. This approach offers a much milder, shorter, and more efficient route to PQ and TQ derivatives than current methods. It is further shown how the optical and electrochemical properties of PQ and TQ can be tuned by choice of appropriate substituents.     

Complete assignment of the 1h- and 13c-nmr spectra of [1]benzothieno[2,3-c]naphtho[1,2-h]quinoline and [1]benzothieno[2,3-c]naphtho[1,2-h][1,2,4]triazolo[4,3-a]quinoline. Concerted use of two-dimensional nmr techniques

The ¹H- and ¹³C-nmr spectra of [1]benzothieno[2,3-c]naphtho[1,2-h]quinoline and [1]benzothieno[2,3-c]-naphtho[1,2-h][1,2,4]triazolo[4,3-a]quinoline were totally assigned using a combination of two-dimensional nmr techniques. After correlation of the proton signals by a COSY spectrum and one-bond heteronuclear correlation, complete assignment of the ¹H- and ¹³C-nmr spectra of the novel heterocyclic compounds required the application of long-range CH coupling information particularly for quarternary resonance assignments and the orientations of individual spin systems relative to one another.     

Pyrrolo[3,2-c][1,2,5]benzotriazocine: A new ring system

A nucleophilic substitution reaction in the pyrrole series, achieved by a neutral nucleophile, led to the key intermediate 7 which by reduction and successive diazotization afforded the new ring system pyrrolo[3,2-c][1,2,5]benzotriazocine 9 in good yield.     

Inhibitors of platelet aggregation. 4. [1,2,5]Thiadiazolo[3,4-c]acridines, 7,8,9,10-Tetrahydro[1,2,5] thiadiazolo[3,4-c]acridities,and 8,9-Dihydro-7H-cyclopenta[b][1,2,5] thiadiazolo[3,4-H]quinolines

The condensation of 4-amino-2,1,3-benzothiadiazole (IV) with diphenyliodonium-2-earboxylate gave N-(2,1,3-benzothiadiazoI-4-yl)anthranilic acid (V) (28%), which was cyclized with phosphorus oxychloride to 6-chloro[1,2,5]thiadiazolo[3,4-c]acridine (VI) (84%). Treatment of VI with 3-(dimethylamino)-1-propanethiol hydrochloride in phenol afforded 6-[ [3-(dimethylamino)-propyl]thio] [1,2,5]thiadiazolo[3,4-c]acridine (VII) (65%). The reaction of IV with a mixture of methyl and ethyl 2-oxocyclohexanecarboxylate gave the adduct, which was ring closed in Dowtherm to 7,9,10,1 1-tetrahydro[1,2,5] thiadiazolo[3,4-c]acridin-6(8H)one (VIII) (70%). Chlorination of VIII with phosphorus oxychloride gave 6-chloro-7,8,9,10-tetrahydro[1,2,5]thiadiazolo[3,4-c]acridine (IX) (84%), which was condensed with 3-(dimethylamino)-1-propanethiol hydrochloride in phenol yielding 6-[ [3-(dimethylamino)propyl]thio]-7,8,9,10-tetrahydrof 1,2,5]-thiadiazolo[3,4-c]acridine (X) (27%). 6-[ [3(1)imethylamino)propyl]thio]-8,9-dihydro-7H-cyclopenta[b] [1,2,5]thiadiazolo[3,4-h]quinoline (XIII) (25%) was prepared similarly from IV and a mixture of methyl and ethyl 2-oxocyclopentanecarboxylate via 7,8,9,10-tetrahydro-6H-cyclopenta[b][1,2,5]thiadiazolo[3,4-h]quinolin-6-one (XI) (85%) and 6-chloro-8,9-dihydro-7H-cyclopenta[b][1,2,5]thiadiazolof3,4-h]quinoline (XII) (56%). The effects of compounds VII-XIII as inhibitors of platelet aggregation are discussed.     

Halogenation of imidazo[4,5-c]pyridinones

Unsubstituted imidazo[4, 5-c]pyridine does not react with chlorine, bromine, or iodine at room temperature or even upon heating to 160°C. The introduction of an oxo group activates the system such that halogenation proceeds readily. Imidazo[4, 5-c]pyridin-4-one gives 7-halo derivatives, while imidazo[4, 5-c]pyridin-2-ones give 4, 7-dihalo products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1076—1081, August, 1994.     

Cyanine dyes from naphtho [1,2-6]thiazolo[3,2-d][1,4]thiazine

Deeply colored cyanine dyes have been synthesized from the previously unknown 3-methyl-12H-naphtho[1,2-b]thiazolo[3,2-d][1,4]thiazinium salts. It is assumed that the deep color of the new cyanines is connected with the conversion of the nonaromatic 1,4-thiazine ring in the dye molecule into an aromatic thiazine ring with three double bonds in a six-membered ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1282–1284, September, 1973.     

Efficient three-step synthesis of benzo[e]imidazo[1,2-c][1,2,3]triazines

A novel three-step sequence toward benzo[e]imidazo[1,2-c][1,2,3]triazine derivatives is investigated. This pathway started from commercially available starting materials afforded 5a–h in good to excellent yields. In this method, we took the advantage of diazonium chemistry, which was followed by intramolecular N-N bond formation in the construction of N-rich cycles.