Synthesis of linear and cyclic compounds containing the 3,4-bis(furazan-3-yl)furoxan fragment

Some chemical transformations of 3,4-bis(4-aminofurazan-3-yl)furoxan (1) and 3,4-bis-(4-nitrofurazan-3-yl)furoxan (2) were considered. Compounds 1 and 2 are valuable synthons for the preparation of linear and cyclic compounds containing the 3,4-bis(furazan-3-yl)furoxan fragment. The reaction of compound 2 with a series of N- and O-nucleophiles afforded novel heterocyclic systems: 7-R-7H-difurazano[3,4-b:3′,4′-f]furoxano[3″,4″-d]azepine and difurazano[3,4-b:3′,4′-f]furoxano[3″,4″-d]oxepin.     

Structural and photoluminescence properties of excited state intramolecular proton transfer capable compounds-potential emissive and electron transport materials

Electronic factors influencing the photoluminescence properties and rates of excited state intramolecular proton transfer (ESIPT) reaction of o-hydroxy derivatives of 2,5-diphenyl-1,3,4-oxadiazole have been studied. The potential of these molecules as emissive and electron transport materials in designing improved organic light emitting diodes (OLEDs) has been studied by analyzing possible reasons for the unusually high Stokes shifts and ESIPT reaction rates. Time-dependent density functional theory (TDDFT) methods have been used to calculate the ground and excited state properties of the phototautomers that are the ESIPT reaction products. We study the relative effect of electron-withdrawing substituents on the proton-acceptor moiety and predict that the lowest ESIPT rate (1.9 x 10(11) s(-1)) is achieved with a dimethylamino substituent and that the Stokes shifts are around 11 000 cm(-1) for all three derivatives.     

Nitration of Chlorobenzene with Nitric Acid in a Continuous Installation

The procedures of production of mononitrochlorobenzene by nitration with 75-97% nitric acid with the yield of the target product of 97.5% were developed. A procedure of precipitation of crystalline p-nitrochlorobenzene from the reaction mixture without additional purification was proposed.     

Basicity of isomeric ditetrazolylbenzenes and their <Emphasis Type="Italic">N-tert</Emphasis>-butyl derivatives

The basicity constants \((pK_{BH^ + } ,pK_{BH^{2 + } } )\) of 1,2-, 1,3-, and 1,4-bis(tetrazol-5-yl)benzenes and their N-tert-butyl derivatives in aqueous sulfuric acid and the dissociation constants (pK _HB) of the corresponding H-complexes with p-fluorophenol in carbon tetrachloride were determined by UV and IR spectroscopy. Mono-and diprotonation of isomeric ditetrazolylbenzenes is observed in the acidity range (H ₀) from ?1 to ?5 (\(pK_{BH^ + } \) ?2.5 to ?3.0; \(pK_{BH^{2 + } } \) ?3.8 to ?4.9). Introduction of a tert-butyl group into the 2-position of the heteroring almost does not affect the basicity of ditetrazolyl benzenes. Among the examined compounds, 1,2-bis(2-tert-butyltetrazol-5-yl)benzene is the strongest proton acceptor with respect to p-fluorophenol as standard proton donor, presumably due to formation of a complex with bifurcated (three-center) hydrogen bond.     

Synthesis and Reactivity of Carbohydroximoyl Azides: I. Aliphatic and Aromatic Carbohydroximoyl Azides and 5-Substituted 1-Hydroxytetrazoles Based Thereon

Chlorination of 1-hydroxyiminopentane gave 1-chloro-1-nitrosopentane which reacted with sodium azide in DMF to form pentanohydroximoyl azide. The azidation of benzohydroximoyl chlorides was always accompanied by decomposition to benzonitriles. Treatment of carbohydroximoyl azides in ether with gaseous hydrogen chloride afforded 5-butyl- and 5-aryl-1-hydroxytetrazoles which reacted with acetic anhydride to form the corresponding acetates.     

Influence on solvent on decomposition rate of benzoyl peroxide in the presence of Et4N·Br or Et4N·Cl

A study has been made of the influence of solvent type on the decomposition rate of benzoyl peroxide, activated by Et₄N·Br or Et₄N·Cl, at 293 K. The reaction rate constant is inversely related to the acceptor properties of the solvent. Quantum-chemical calculations have been performed on the associates [Solv...Hal]^–, and the experimental and calculated data have been analyzed jointly.L. M. Litvinenko Institute of Physical-Organic and Coal Tar Chemistry, National Academy of Sciences of the Ukraine, 70 R. Luxembourg Street, Donetsk 340114, Ukraine. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol, 32, No. 2, pp. 88–91, March–April, 1996. Original article submitted June 13, 1995.     

Nitro derivatives of 1,3-dihydrobenzimidazol-2-one: I. Synthesis of <Emphasis Type="Italic">N</Emphasis>-nitrobenzimidazol-2-ones

1,3,5,6-Tetranitro-2,3-dihydro-1H-benzimidazol-2-one, 1,5,6-trinitro-2,3-dihydro-1H-benzimidazol-2-one, and 1,4,5,6-tetranitro-2,3-dihydro-1H-benzimidazol-2-one were synthesized for the first time by nitration of 5,6-di- and 4,5,6-trinitro-2,3-dihydro-1H-benzimidazol-2-ones with concentrated nitric acid in acetic anhydride.     

Oxidative coupling of the azide ion with anions of primary nitroalkanes. Synthesis of 1-azido-1-nitroalkanes

The reaction of salts of 1-aci-nitroethane and 1-aci-nitrobutane with sodium azide and ammonium peroxodisulfate in the methylene chloride—water two-phase system affords 1-azido-1-nitroethane and 1-azido-1-nitrobutane, respectively.