1-Methyl-2-(1′-methyl-2′-pyrrolyl)-1H-phenanthro[9,10-d]-imidazole. Synthesis and electrophilic substitution reactions

2-(1′-Methyl-2′-pyrrolyl)-1H-phenanthro[9,10-d]imidazole was synthesized by heating 9,10-phenanthrenequinone and 1-methyl-2-pyrrolecarboxaldehyde in glacial acetic acid in the presence of ammonium acetate. The reactions of electrophilic substitution (nitration, bromination, sulfonation, formylation, acylation) were studied for the product of its N-methylation in the KOH-DMSO medium. The electrophilic attack was found to affect exclusively the pyrrole ring.     

Bromination of deactivated polycyclic aromatic nitro compounds

Bromination of 2,7-dinitro-9,10-phenanthrenequinone, 2,5-dinitro-9,10-phenanthrenequinone, and 2,4,7-trinitrofluorenone with bromine in concentrated sulfuric acid in the presence of acetic acid gave, respectively, 4-bromo-2,7-dinitro-9,10-phenanthrenequinone, 2-bromo-4,7-dinitro-9,10-phenanthrenequinone, and 5-bromo-2,4,7-trinitrofluorenone. No bromination occurred in the absence of nitric acid. The same brominated polynitro compounds can be obtained under analogous conditions directly from unsubstituted 9,10-phenanthrenequinone and fluorenone.     

Synthesis and reactions of trinitro-9,10-phenanthrenequinone derivatives

The reaction of 2,4,7-trinitro-9,10-phenanthrenequinone with CuCl in aqueous dimethylformamide or dimethyl sulfoxide at room temperature, followed by acidification, gave a stable red complex of 2,4,7-trinitro-9,10-dihydroxyphenanthrene with a solvent molecule. On heating in a polar aprotic solvent in the presence of CuCl or other metal salt, 2,4,7-trinitro-9,10-phenanthrenequinone underwent benzilic acid rearrangement with formation of 2,4,7-trinitrofluorenone. The nitration of 9,10-sulfuryldioxyphenanthrene and subsequent decomposition of cyclic sulfates afforded previously unknown 1,3,6-trinitro- and 1,8-dinitro-9,10-phenanthrenequinones.     

Reactions of Phenols with Lewis Acids: XIX. Complexes of ortho-Quinones and Benzenediols with Aluminum Bromide

Enthalpies of the reactions of Al₂Br₆ with 3,5-di-tert-butyl-1,2-benzoquinone, 1,2-naphthoquinone, 9,10-phenanthrenequinone, dimedone, isomeric benzenediols, and 4-methoxyphenol have been determined.     

Flow-injection determination of 9,10-phenanthrenequinone with catalytic photometric detection

A catalytic photometric method with a flow-injection system is described for the determination of 9,10-phenanthrenequinone. It is based on the catalytic effect of 9,10-phenanthrenequinone on the redox reaction of 1,2-dinitrobenzene with formaldehyde under alkaline conditions. 9,10-Phenanthrenequinone at the 5.0 x 10(-8)-5.0 x 10(-6)M level can be determined at a rate of 20 samples/hr. The detection limit is 1.0 x 10(-8)M (40 pg in a 10-microl injection).     

Products and mechanisms of photochemical transformations of <Emphasis Type="Italic">o</Emphasis>-quinones

The photochemical transformations of quinones by the action of light at λ > 500 nm, namely, the photodecarbonylation and photoreduction reactions were studied with the use of a series of o-benzoquinones and 9,10-phenanthrenequinone as examples. The two-stage mechanism of the decarbonylation reaction of o-benzoquinones was established. At the first stage, rearrangement of a photoexcited quinone molecule into a bicyclic compound that spontaneously decomposes in the dark reaction into cyclopentadienone and CO takes place. It has been found that the formation of the photoreduction products of both o-benzoquinones and 9,10-phenanthrenequinone in the presence of various H donors (N,N-dimethylanilines and polymethylbenzenes) follows the same mechanism. In the first step, a phenol ether is produced, which subsequently undergoes quantitative transformation into pyrocatechol or ketol via the heterolytic mechanism. The stability of phenol ethers is determined by the structure and redox properties of the reactants.     

Synthesis and Properties of 2-(2-Furyl)- and 2-(2-Thienyl)-1-methylphenanthro[9,10-d]imidazoles

Condensation of 9,10-phenanthrenequinone with 2-furaldehyde and 2-thiophenecarbaldehyde in glacial acetic acid in the presence of ammonium acetate gave 2-(2-furyl)- and 2-(2-thienyl)phenanthro[9,10-d]imidazoles which were converted into the corresponding 1-methyl derivatives. The furan and thiophene rings in the products lose their acidophobic properties. Depending on the conditions, electrophilic substitution reactions in 2-(2-furyl)- and 2-(2-thienyl)phenanthro[9,10-d]imidazoles occur both at the furan (thiophene) and phenanthrene moieties.     

Palladium(II) 9,10-phenanthrenequinone N-substituted thiosemicarbazone/semicarbazone complexes as efficient catalysts for N-arylation of imidazole

A series of palladium complexes, [PdCl(L_1–4)] (1–4) (L₁ = 9,10-phenanthrenequinone thiosemicarbazone, L₂ = 9,10-phenanthrenequinone methylthiosemicarbazone, L₃ = 9,10-phenanthrenequinone phenylthiosemicarbazone, and L₄ = 9,10-phenanthrenequinone semicarbazone), have been synthesized and characterized by elemental analyses, UV–vis, FT-IR, ¹H and ¹³C NMR, and ESI-Mass spectroscopic methods. The catalytic efficiency of the synthesized complexes was examined against N-arylation of imidazole. The system works well with the electron-rich, -neutral, and -deficient aryl halides to afford the products in good to excellent yields. Sterically congested aryl halides and heteroaryl halides have also been used as substrates to provide N-arylated heterocycles. In addition, this methodology can be applicable to other substrates with N-containing heterocycles.     

Specific features of the photolytic transformations of the polynuclear quinone-aliphatic hydrocarbon systems

Dependence of the quantum yield of decomposition of quinone on the intensity of the absorbed irradiation in the compositions of 1,2-naphthoquinone, 9,10-phenanthrenequinone, and 4-nitro-9,10-phenathrenequinone with nonane has the extremal character.     

A procedure for preparing 4-cyanofluoren-9-one

A procedure was developed for preparing 4-cyanofluoren-9-one by intramolecular cyclization of 9,10-phenanthrenequinone monooxime benzenesulfonate.     

Quantum-Chemical Simulation of the Structure of Charge-Transfer Complexes of 9,10-Phenanthrenequinone Nitro-Derivatives with Phenanthrene. Crystal and Molecular Structure of 1 : 1 Complex of 2,4,7-Trinitro-9,10-phenanthrenequinone with Phenanthrene

Russian Journal of General Chemistry - Data on the structure and properties of charge transfer complexes of nitro derivatives of 9,10-phenanthrenequinone (acceptor) with phenanthrene (donor) were...     

Products of photoreduction of 9,10-phenanthrenequinone in the presence of N,N-dimethylanilines and polymethylbenzenes

Photoreduction of 9,10-phenanthrenequinone (PQ) in the presence of p-substituted N,N-dimethylanilines and polymethylbenzenes affords corresponding phenolethers as primary products. In the subsequent process shielded from light, phenolethers, which were formed by photoreaction of PQ with N,N-dimethylanilines, were quantitatively converted to give corresponding ketols. Phenolethers of 9,10-phenanthrenequinone and polymethylbenzenes are rearranged only under irradiation and in the presence of second molecule of PQ to form ketols. Stability of phenolethers is determined by redox properties and structure of hydrogen donors.     

A stable fused bicyclic disilene as a model for silicon surface

We synthesized the first fused bicyclic disilene 1 representing topologically a partial structure of the Si(001) surface up to the third layer. In the solid state, the five-membered rings adopt the envelope conformation, and the Si=Si double bond in 1 exists in the slightly cis-bent form (bent angle theta is 3.6 degrees ) compared to that of the highly cis-bent dimer on the Si(001) surface. Highly symmetric 1H NMR spectral pattern of 1 remains even at -80 degrees C, indicating the facile ring flipping of the bicyclic skeleton in solution. While syn-adduct was obtained in the reaction of 1 with water, anti-addition of chlorine atoms across the Si=Si double bond in 1 was observed in the reaction with carbon tetrachloride. The structural characteristics of the 9,10-phenanthrenequinone adduct 7 are in good accord with those of the proposed structure of the 9,10-phenanthrenequinone molecule adsorbed on the Si(001) surface.     

Hypercoordinate germanium complexes with phenanthrene-9,10-diolate ligands: synthesis,structure, and electronic properties

The synthesis, molecular structure, and electronic properties of sodium tris(phenanthrene-9,10-diolato)germanate(iv) are described. The germanate complex is readily oxidized in air to produce 9,10-phenanthrenequinone, and the resulting quinones and the ligands reveal intermolecular π-stacking interaction in the polymeric association in the solid state. Addition of phenanthroline to the germanate complex leads to a monomeric structure.     

N,N′-Disubstituted phenanthrene-9,10-diimines: synthesis and NMR spectroscopic study

Novel aryl-aryl, alkyl-alkyl, aryl-alkyl N,N′-disubstituted phenanthrene-9,10-diimines were synthesized by condensation of 9,10-phenanthrenequinone with primary amines. The novel two-stage method of synthesis of disubstituted phenanthrene-9,10-diimines with identical or different aryl and alkyl substituents at the nitrogen atom was established. The investigated compounds undergo slow Z-E/E-Z interconversion which was studied by NMR spectroscopy. Thermodynamic parameters of interconversion were obtained by variable temperature NMR spectroscopy.     

Enantioselective [4+2] cycloaddition of ketenes and 9,10-phenanthrenequinone catalyzed by N-heterocyclic carbenes

Chiral N-heterocyclic carbenes were found to be efficient catalysts for the formal [4+2] cycloaddition reaction of alkyl(aryl)ketenes and 9,10-phenanthrenequinone to give the corresponding cycloadducts in good yields with high enantioselectivities.     

3,6,9,10-tetrahalogenphenanthrene. A new cycliarylation reaction of DDT-derivatives

A simple synthesis of tetrachlorophenanthrene starting from DDT has been realized. 1,1,1,2-tetrachloro-2,2-bis-(4-chlorophenyl)-ethane (I) and its rearranged product 1,1,2,2-tetrachloro-1,2-bis-(4-chlorophenyl)-ethane (V) and other analogs substituted by halogen in the para-position undergo a cycliarylation yielding 3,6,9,10-tetrahalogenophenanthrenes. Partial dechlorination of this tetrachlorophenanthrene yields 3,6-dichlorophenanthrene. Oxidation gives 3,6-dichloro-9,10-phenanthrenequinone, and chlorosulfonation leads to 3,6,9,10-tetrachloro-2,7-bis-(chlorosulfonyl)-phenanthrene. The mechanism of this cyclization reaction in presence of LEWIS acids is discussed and compared with the cyclization of DDT derivatives to yield fluorenones.     

2-Methylpyridinium salts as 1,4-dinucleophiles. IV. Westphal condensation with 2-alkyl-1-aminoazinium substrates

Condensation of 2-alkyl-1-aminopyridinium, quinolinium or 1-alkyl-2-aminoisoquinolinium salts with 1,2-acenaphthenequinone or 9,10-phenanthrenequinone in the presence of base, gave pyrido[1,2-b]pyridazinium salts in good yields.     

STABILIZATION OF SEMIQUINONE INTERMEDIATES IN THE PHOTOREDUCTION OF PHENANTHRENEQUINONE BY COMPLEX FORMATION

Abstract— The yellow color of 9,10-phenanthrenequinone in alcohol solution is bleached under the influence of exciting radiation in a band of wavelengths extending from the ultraviolet to the visible green. The bleaching is due to a photoreduction of the quinone yielding 9,10-dihydroxyphenanthrene. In the presence of certain divalent metal ions, irradiation of the quinoid material results in a blue-green long lived intermediate which may be further photo-reduced to the colorless 9,10-diol. The blue-green photo-intermediate is a cation-semiquinone complex.     

Reactions of 9,10-phenanthrenequinone and its nitro derivatives with acetone in the presence of Al2O3

The addition of acetone to 9,10-phenanthrenequinone and 2-nitro-, 2,7-dinitro-, and 2,4,7-trinitro-9,10-phenanthrenequinones in the presence of Al₂O₃ affords mono- and bisadducts. The crystal structures of 10-hydroxy-10-(2-oxopropyl)-2-nitro-9,10-dihydrophenanthren-9-one and 9,10:10,9-bishemiketal of 9,10-dihydroxy-2-nitro-9,10-bis(2-oxopropyl)-9,10-dihydrophenanthrene were determined.