Benzonitrile structure

Another ether-type BMI, 2,6-(3-maleimidophenoxy) benzonitrile (34), is synthesized from 2,6 dichlorobenzonitrile as a precursor, again via the standard route described above. The benzonitrile structural unit in the BMI backbone is responsible for the Tg (404°C) of the cured homopolymer. 

The isolation in poor yield of 2,5,5-triphenyl-4(5f )-oxazolone (82) by reaction of benzilic acid with benzonitrile in concentrated sulfuric acid was claimed by Japp and Findlay. Cornforth, however, suggested that the reactions of this product, m.p. 136°, could be accounted for more satisfactorily by the isomeric 5(4i ) structure 83. 

Much earlier information on the structure of diazonium ions than that derived from X-ray analyses (but still useful today) was obtained by infrared spectroscopy. The pioneers in the application of this technique to diazonium and diazo compounds were Le Fevre and his school, who provided the first IR evidence for the triple bonds by identifying the characteristic stretching vibration band at 2260 cm-1 (Aroney et al., 1955 see also Whetsel et al., 1956). Its frequency lies between the Raman frequency of dinitrogen (2330 cm-1, Schrotter, 1970) and the stretching vibration frequency of the C = N group in benzonitrile (2255 cm-1, Aroney et al., 1955). In substituted benzenediazonium salts the frequency of the NN stretching vibration follows Hammett op relationships. Electron donor substituents reduce the frequency, whereas acceptor substituents increase it. The 4-dimethylamino group, for example, shifts it by 103 cm-1 to 2177 cm-1 (Nuttall et al., 1961). This result supports the hypothesis that... 

Scheme 1. Structures of 4-(trans-4-n-pentylcyclohexyl)benzonitrile (PCH5) and 4-(trans-4-n-prop-ylcyclohexyl)benzonitrile (PCH3)...

This reaction may be visualized as proceeding by nucleophilic attack of tervalent phosphorus at the carbonyl group to give an intermediate such as (15). The structure of (16) was deduced from the fact that it was hydrolysed to the known phosphine oxide (17). Methylenephosphoranes (phosphorus ylides) may also be converted into monophosphazenes by reaction with benzonitrile ... 

Corsaro and co-workers studied the reaction of pyridazine, pyrimidine, and pyrazine with benzonitrile oxide and utilized H NMR spectral analysis to determine the exact structure of all the cyclized products obtained from these reactions <1996T6421>, the results of which are outlined in Table 1. The structure of the bis-adduct product 21 of reaction of pyridazine with benzonitrile oxide was determined from the chemical shifts of the 4- and 5-isoxazolinic protons at 3.76 and 4.78 ppm and coupled with the azomethine H at 6.85 ppm and with the 5-oxadiazolinic H at 5.07 ppm, respectively. They determined that the bis-adduct possessed /(-stereochemistry as a result of the large vicinal coupling constant (9.1 Hz). Similarly, the relative stereochemistry of the bis-adducts of the pyrimidine products 22-25 and pyrazine products 26, 27 was determined from the vicinal coupling constants. 

Similarly, other cycloadducts of nitrile oxides with C6o were synthesized. The cycloadducts were characterized by 13C NMR spectroscopy and high-resolution fast atom bombardment (FAB) mass spectrometry. It should be mentioned that X-ray structure determination of the 3-(9-anthryl)-4,5-dihydroisoxazole derivative of C6o, with CS2 included in the crystals, was achieved at 173 K (255). Cycloaddition of fullerene C60 with the stable 2-(phenylsulfonyl)benzonitrile oxide was also studied (256). Fullerene formed with 2-PhSC>2C6H4CNO 1 1 and 1 2 adducts. The IR, NMR, and mass spectra of the adducts were examined. Di(isopropoxy)phosphorylformonitrile oxide gives mono- and diadducts with C60 (257). Structures of the adducts were studied using a combination of high performance liquid chromatography (HPLC), semiempirical PM3 calculations, and the dipole moments. 

Dipolar cycloaddition of 2,4-(trimethylsilyl)- and 2,4-(trimethylgermyl)-substituted thiophene-1,1-dioxides as well as silylated 2,2 -bithiophene-1,1-dioxides was investigated. It was shown that only the C(4)=C(5) double bond of 2,4-disubstituted thiophene-1,1-dioxides interacts with acetonitrile oxide to give thienoisoxazoline dioxides. Bithiophene derivatives were inactive or their reaction with nitrile oxide was accompanied by desilylation. Cycloaddition of benzonitrile oxide with all mentioned sulfones did not occur. The molecular structure of 3a-methyl-5.6a-bis(trimethylgermyl)-3a,6a-dihydrothieno 2.3-c/ isoxazole 4,4-dioxide was established by X-ray diffraction (263). ... 

Benzonitrile oxide, generated by dehydrochlorination of benzohydroximoyl chloride, undergoes regio- and face-selective cycloadditions to 6,8-dioxabicyclo [3.2.1]oct-3-ene 108a yielding a 4 1 mixture of 4,5-dihydroisoxazoles 109 and 110. Both products have exo-stereochemistry, resulting from the approach of the nitrile oxide from the face opposite to the the methyleneoxy bridge. Structures of the adducts were determined by 1 H NMR spectroscopy and, in the case of compound 109, by X-ray diffraction analysis (275). 

Later it was shown in reactions of aromatic aldehyde methylhydrazones 137a-f with benzonitrile oxide that the initially formed Z-adduct 138, depending on the reaction procedure and the substituents, undergoes either isomerization to the thermodynamically stable E-adduct 139, tautomerization to an oxatriazine 140 or irreversible cyclization to a triazole 141 (Scheme 1.28). The structure of 4-methyl-3.6-diphenyl-5,6-dihydro-4//-1,2.4,5-oxatriazinesl40a was confirmed by an X-ray study (308). 

Cyclopentadienylamine)scandium(2,3-dimethyl-l,3-butadiene) 7 was synthesized in good yield, as shown in Scheme 2. Complex 7 reacted with benzonitrile to form a /rz-imido complex 8, the structure of which was characterized by single crystal X-ray diffraction. This product 8 was proposed to be formed by nitrile insertion followed by an attack of another diene methylene group on the carbon atom of the imido intermediate.3 An unsaturated metal imido species was formed, which easily dimerized to produce 8. However, the yield of 8 was not reported. 

The PHOX ligands have a modular structure (Scheme 29.1). They are synthesized from chiral amino alcohols and benzonitrile or bromobenzonitrile the... 

Since the hybridization and structure of the nitrile group resemble those of alkynes, titanium carbene complexes react with nitriles in a similar fashion. Titanocene-methylidene generated from titanacyclobutane or dimethyltitanocene reacts with two equivalents of a nitrile to form a 1,3-diazatitanacyclohexadiene 81. Hydrolysis of 81 affords p-ketoena-mines 82 or 4-amino-l-azadienes 83 (Scheme 14.35) [65,78]. The formation of the azati-tanacyclobutene by the reaction of methylidene/zinc halide complex with benzonitrile has also been studied [44]. 

When (40) is irradiated by Hg lamp at room temperature in the presence of pentamethyl-cyclopentadienyl dicarbonyl cobalt(III), Co(III) dithiolato complexes (45) and (46) are formed implying involvement of benzonitrile sulfide as an intermediate <92CL243). Thermolysis of (40) (and its phenyl ring substituted derivatives (40a)) at 110-140 °C in aromatic solvents results in formation of another heterocyclic mesoionic structure (47) and appears to proceed as a radical process (Scheme 2) (91TL4023). The reaction is inhibited by radical scavengers. 

When deprotonated dimethyl sulfone is reacted with 2 equiv of benzonitrile, compound 109 is obtained in low yield (Equation 91) <1973JOM(59)53>. Compounds of the general structure 179 can be prepared from two molecules of enamino esters 288 and sulfur dichloride or disulfur dichloride <1984JOG4780> or in low yield using chlorocarbo-nylsulfenyl chloride 289 as the source of sulfur <1985JHC1621> (Equation 92). A series of cycloadditions lead to the formation of 131 from 290 and two molecules of the ynamine 291 (Scheme 69) <1995LA1795>. 

Techert S, Zachariasse KA (2004) Structure determination of the intramolecular charge transfer state in crystalline 4-(diisopropylamino)benzonitrile from picoseconds X-ray diffraction. J Am Chem Soc 126 5593-5600... 

Fukuzumi and co-workers described spectroscopic evidence for a ix-rf- ] -peroxo-(Cu )2 species stabilized with a fcidentate nitrogen ligand, but no (catalytic) oxidation behavior towards catechol was noted (a related trinu-clear copper species converted 2,4-di-ferf-butylphenol stoichiometrically towards the biphenol derivative) [224], Stack et al. have described a similar ] -peroxo-(Cu )2 species (28, vide supra) that could be considered a structural and functional model for tyrosinase-activity, as it efficiently reacted with catechol, benzyl alcohol and benzylamine to yield quinone (95%), benzaldehyde (80%) and benzonitrile (70%) [172,173]. This dinuclear per-0X0 species is generated by association of two monomeric copper centers, in contrast to the systems based on dinucleating Ugand scaffolds described above. 

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