Benzonitrile substituted

Ruthenium(II) Treatment of [Ru(NH3)5(OH2)] or [Ru(NHj)5(acetone)] with L or [RuC1(NHj)5] with zinc amalgam in the presence of L yields [RuL(NH3)s] (L = acetonitrile, benzonitrile, substituted benzonitrile, - acrylonitrile, hydrogen cyanide, ethyl cyano-formate, dicyanamide, malononitrile, substituted malononitrile, tricyanomethanide, 4-cyano-l-methylpyridinium ). Reaction of a hundred-fold excess of RCHO (R = Ph, Me) with [Ru(NHj)j] under alkaline conditions yields [Ru(NH3)5NCR] .The likely mechanism of this reaction is given in Scheme 12. An alternative route to nitrile complexes is by reaction of [Ru(NH3)sOH2] with aldoximes, e.g. RMeC=NOH, to afford [Ru(NH3)5(NCMe)] and... 

The higjily water-soluble dienophiles 2.4f and2.4g have been synthesised as outlined in Scheme 2.5. Both compounds were prepared from p-(bromomethyl)benzaldehyde (2.8) which was synthesised by reducing p-(bromomethyl)benzonitrile (2.7) with diisobutyl aluminium hydride following a literature procedure2.4f was obtained in two steps by conversion of 2.8 to the corresponding sodium sulfonate (2.9), followed by an aldol reaction with 2-acetylpyridine. In the preparation of 2.4g the sequence of steps had to be reversed Here, the aldol condensation of 2.8 with 2-acetylpyridine was followed by nucleophilic substitution of the bromide of 2.10 by trimethylamine. Attempts to prepare 2.4f from 2.10 by treatment with sodium sulfite failed, due to decomposition of 2.10 under the conditions required for the substitution by sulfite anion. 

Nitration using this reagent was first investigated, by Francis. He showed that benzene and some of its homologues bromobenzene, benzonitrile, benzoyl chloride, benzaldehyde and some related compounds, and phenol were mono-nitrated in solutions of benzoyl nitrate in carbon tetrachloride anilines would not react cleanly and a series of naphthols yielded dinitro compounds. Further work on the orientation of substitution associated this reagent with higher proportions of o-substitution than that brought about by nitric acid this point is discussed below ( 5.3.4). 

Irradiation of l//-indazoles under nonacidic conditions resulted in isomerization to benzimidazoles and also ring opening to isomeric benzonitriles. With 1-substituted benzimidazoles and sensitized irradiation, nitriles were formed, but these are only minor products with other substitution patterns 67HCA2244, 64TL2999). Irradiation of benzimidazoles leads to oxidative dimerization. 

Alkylarylisoxazoles can be obtained from the cycloaddition of nitrile Af-oxides to substituted alkynes or alkenes (Section 4.16.4.1.2(ii)), and from the condensation of the 1,4-dilithio oximes (358) with benzonitriles (72JHC183) or amides (78JOC3015). 

The 1,3-dipolar eyeloaddition of nitrile oxides to 2(5//)-furanones substituted at C5 by sulfur-bearing groups were also studied with respeet to the regio- and ste-reoseleetivity of the reaetion (96T3457). Benzonitrile oxide (R = Ph), for... 

Attempts have been made to catalyze the arrangement of 3-oxaquadricyclane to oxepins with transition-metal complexes.1 32 1 35 When dimethyl 2,4-dimethyl-3-oxaquadricyclane-l,5-dicarboxylate is treated with bis(benzonitrile)dichloroplatinum(II) or dicarbonylrhodium chloride dimer, an oxepin with a substitution pattern different from that following thermolysis is obtained as the main product. Instead of dimethyl 2,7-dimethyloxepin-4,5-dicarboxylate, the product of the thermal isomerization, dimethyl 2,5-dimethyloxepin-3,4-dicarboxylate (12), is formed due to the cleavage of a C O bond. This transition metal catalyzed cleavage accounts also for the formation of a 6-hydroxyfulvene [(cyclopentadienylidene)methanol] derivative (10-15%) and a substituted phenol (2-6%) as minor products.135 The proportion of reaction products is dependent on solvent, catalyst, and temperature. 

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... 

Triazines have been prepared by microwave-assisted reaction of substituted benzonitriles 161 and cyanoguanidines 162 using the ionic hquid [bmim][PF6] as the solvent at 130°C for 10-15 min [106]. Nine differently... 

Huisgen et al. also studied the thermal decomposition of ethyl diazoacetate in the presence of benzonitrile and phenylacetonitrile to give the corresponding 2-substituted-5-ethoxy oxazoles 3 in variable yields (Scheme 3).<64CB2864> The authors found that the solvent had an effect on the rate of decomposition of ethyl diazoacetate in the polar solvent, niuobenzene, the rate was found to be twice that in the hydrocarbon solvent, decalin. 

Scheme 11.11 gives some representative preparative reactions based on these methods. Entry 1 is an example of the classical procedure. Entry 2 uses crown-ether catalysis. These reactions were conducted in the aromatic reactant as the solvent. In the study cited for Entry 2, it was found that substituted aromatic reactants such as toluene, anisole, and benzonitrile tended to give more ortho substitution product than expected on a statistical basis.180 The nature of this directive effect does not seem to have been studied extensively. Entries 3 and 4 involve in situ decomposition of A-nitrosoamides. Entry 5 is a case of in situ nitrosation. 

In considering an appropriate starting material for the synthesis of taranabant the commercial availability of a number of 3-substituted benzonitriles was evaluated, however, with the exception of the previously employed 3-bromobenzonitrile, cost effective options from recognized large-scale suppliers were limited (Figure 9.2). 

A DFT-HSAB study provides a quantitative rationalization of regioselectivity in 1,3-DC of 4-substituted benzonitrile oxides towards methyl propiolate not amenable to FMO and electron-demand theory <06CEJ1156>. 

Kobayashi and co-workers have also reported an alternate synthesis of 1,4-disubstituted isoquinolines and a new synthesis of 1,3,4-dihydroisoquinoline derivatives <06BCJ 1126 06S2934>. The 1,4-disubstituted isoquinolines 121 are synthesized in good yields by reacting a variety of organolithiums 122 with different benzonitriles 123. In addition, a variety of lithium dialkylamides 124 were also reacted with different benzonitriles 123 to form 1 -amino-4-substituted isoquinolines 121 in moderate yields. 

Nucleophilic substitution of the fluorine atom in 2-fluorobenzonitrile 30 by 1,2,4-triazole gave a 10 1 mixture of 2-[l,2,4]-triazol-l-yl benzonitrile 31 and the corresponding 4-isomer 32 in crude yield of 66% (Equation 6) <2004JME2995>. 

Interesting oxadiazole-substituted benzonitriles prepared from the respective aryl iodides were transformed into the corresponding (dioxadiazolephenyl)tetrazoles. Despite the high temperature and other drastic conditions, the oxadiazole ring stayed intact during both reactions (Scheme 20) <1999JOC6425>. 

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