Nitrobenzonitrile

3-Nitro-4-aminoanisole (16.8 g., 0.10 mole) [Org. Syntheses, 25, 78 (1945) ] is added to a solution of 30 ml. of concentrated sulfuric acid and 100 ml. of water, and the resulting mixture is cooled to 0-5°. A solution of 7 g. (0.102 mole) of sodium nitrite in 20 ml. of water is added slowly at this temperature, and the mixture is allowed to stand for 2 hours at 0-5°. After filtration to remove a small amount of 3-nitro-4-aminoanisole, the filtrate is added dropwise to a boiling mixture of 100 ml. of water, 6.4 g. of copper sulfate, 15.6 g. of sodium bromide, and 2 g. of copper powder. After another 30-minute boiling, the mixture is cooled and extracted with ether. The ethereal extracts are washed with water, dried over calcium chloride, and distilled. 3-Nitro-4-bromoanisole boils at 153-154°/13 mm. and is obtained in a 75% yield (17.5 g.). 

A mixture of 50 g. (0.30 mole) of carbazole and 400 ml. of glacial acetic acid is heated to boiling and then cooled somewhat. Twenty-one grams (0.33 mole) of sodium nitrite is added to the stirred mixture in small portions at such a rate that the temperature of the mixture remains below the boiling point. There is next added, in the same manner as before, 83 ml. of a mixture of equal portions of acetic acid and nitric acid (sp. gr. 1.4). The precipitated crystalline material is filtered off and washed with ethanol. This material is 3-nitro-9-nitrosocarbazole, and it may be further purified by recrystallization from ethanol or ethyl acetate. 

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The chemistry of indium metal is the subject of current investigation, especially since the reactions induced by it can be performed in aqueous solution.15 The selective reductions of ethyl 4-nitrobenzoate (entry 1), 2-nitrobenzyl alcohol (entry 2), l-bromo-4-nitrobenzene (entry 3), 4-nitrocinnamyl alcohol (entry 4), 4-nitrobenzonitrile (entry 5), 4-nitrobenzamide (entry 6), 4-nitroanisole (entry 7), and 2-nitrofluorenone (entry 8) with indium metal in the presence of ammonium chloride using aqueous ethanol were performed and the corresponding amines were produced in good yield. These results indicate a useful selectivity in the reduction procedure. For example, ester, nitrile, bromo, amide, benzylic ketone, benzylic alcohol, aromatic ether, and unsaturated bonds remained unaffected during this transformation. Many of the previous methods produce a mixture of compounds. Other metals like zinc, tin, and iron usually require acid-catalysts for the activation process, with resultant problems of waste disposal. 

The 3,4-bis(4-fluorophenyl)-l,2,5-oxadiazole 2-oxide 324 was found as a side product in the synthesis of isoxazole derivatives (Scheme 82, method A) <2006AXEo4827>. Dimerization of 3- and 4-nitrobenzonitrile A-oxides gave corresponding 1,2,5-oxadiazole A-oxides (Scheme 82, method B) <1999MI111>. 

Aromatic nitriles differ from their aliphatic cousins in that they bear no H-atoms at C(a) and, hence, cannot undergo oxidative denitrilation. Here, hydrolysis of the CN group depends on the substrate properties and on the relative efficiency of competitive reactions such as ring hydroxylation. Thus, the CN group of benzonitrile (11.87, R = H), 2- and 4-hydroxybenzonitriles (11.87, R = 2-OH or 4-OH), and 4-nitrobenzonitrile (11.87, R = 4-N02) was not hydrolyzed by rat liver subcellular preparations [124],... 

The photoreduction of eight electron-acceptor- and four electron-donor-substituted nitrobenzenes has been studied and quantum yields for either starting material disappearance or product formation have been reported 7). Photolysis of 4-nitrobenzonitrile and 4-nitrotoluene in air-saturated solutions was completely quenched and thus a triplet multiplicity of the reacting excited state was derived 7). 

Nese C, Schuchmann MN, Steenken S, von Sonntag C (1995) Oxidation vs. fragmentation in radiosensitization. Reactions of a-alkoxyalkyl radicals with 4-nitrobenzonitrile and oxygen. A pulse radiolysis and product study. J Chem Soc Perkin Trans 2 1037-1044 Neta P, Huie RE, Mosseri S, Shastri LV, Mittal JP, Maruthamuthu P, Steenken S (1989) Rate constants for reduction of substituted methyl peroxyl radicals by ascorbate ions and N,N,N, N -tetrameth-yl-p-phenylenediamine. J Phys Chem 93 4099-4104 Neta P, Huie RE, Ross AB (1990) Rate constants for reactions of peroxyl radicals in fluid solutions. J Phys Chem Ref Data 19 413-513... 

Supercritical carbon dioxide with a minute co-solvent addition is an effective medium for the 1,3-dipolar cycloaddition of azomethine ylides with DMAD to produce substituted pyrroles.67 The 1,3-dipolar cycloaddition of nitrile ylides [e.g. benzonitrile (4-nitrobenzylide) and 4-nitrobenzonitrile(benzylide)] with acrylamides provided a synthesis of 3,4-dihydro-2//-pyrroles with moderate to good yields.68 The Pt(II)-or Au(III)-catalysed 3 + 2-cycloaddition of the transition metal-containing azomethine ylide (63) with electron-rich alkenes provided a carbene complex (64), which yields tricyclic indoles (65) having a substituent at 3-position (Scheme 17).69 The 1,3-dipolar cycloadditions of azomethine ylides with aryl vinyl sulfones are catalysed by Cu(MeCN)4C104-Taniaphos with nearly complete exo- selectivity and enantioselec-tivities up to 85% ee.10 The 3 + 2-cycloaddition of benzol/>]thiophene 1,1-dioxide... 

When chloro- and dichloroacetonitriles were reacted with o-aminocar-bonitrile 52, 4-chloro-2-chloromethyl- and 4-chloro-2-dichloromethyl-thieno[2,3-J]pyrimidines 53a and 53b were obtained, respectively. For compounds with stronger electron-withdrawing substituents on the C=N group, such as ethyl cyanoacetate, ethyl cyanoformate, 4-nitrobenzylcyanide, 4-nitrobenzonitrile, phenoxyacetonitrile, phenylthioacetonitrile, phenylsul-... 

Nitrile oxides have also been examined as reagents towards benzoyl-substituted 1,1-enediamines 8178,179. Due to the rapid dimerization of the nitrile oxide, no reaction between 8 and 4-nitrobenzonitrile oxide took place. However, 8 reacts smoothly with... 

The two competing transition states for the cycloaddition between 4-nitrobenzonitrile oxide and 4,4-dimethyl-3-hydroxypentene have been calculated by a combination of ab initio and MM2 calculations35. Since the same sense of selectivity and the same type of interactions are expected in the osmylation reaction, extrapolation of these results to the latter transformation has been proposed (model C). The major product is believed to arise from the staggered36, 37 transition state which has the best ff-donor (alkyl, silyl or stannyl) anti to maximize electron donation from its high lying orbital to the LUMO of the transition state. Since this structure implies a [3 + 2]-type cycloaddition, the inside position, less crowded than the outside position, is best occupied by the oxygen atom. 

Only a few examples of cycloadditions on alkenes with an alkyl or silyl substituted allylic stereocenter are known144 148-149. One is the cycloaddition of 4-nitrobenzonitrile oxide Lo a series of racemic 3-methyl-l-alkenesl49. 

The cyano compound, 4-nitrobenzonitrile with the lithium alkoxide shown furnished an ether in 50% yield by stirring at 25°C for 18 hours (ref.58). 

More recently, Houk et al. (1986 b) demonstrated that the steric interaction in dipolar cycloaddition can be reproduced by molecular mechanics calculations (MM2) of transition state models. These calculations are in good agreement with experimental diastereomer ratios in the reaction of 4-nitrobenzonitrile oxide with various 3-substituted but-l-enes. 

More recent studies have provided interesting new information. A comparison was made of the reactions of 4-nitrobenzonitrile or oxygen with a-alkoxyalkyl radicals, models for DNA sugar radicals, produced via reaction of OH with e.g. 

C. Nese, M.N. Schuchmann, S. Steenken and C. von Sonntag, Oxidation vs. fragmentation in radiosensitization. Reactions of a-alkoxyalkyl radicals with 4-nitrobenzonitrile and oxygen. A pulse radiolysis and product analysis study, J. Chem. Soc., Perkin Trans. 2, (1995) 1037. 

The IMS instrument used in these studies was a Smiths lONSCAN operating in the negative polarity mode with purified air as the buffer gas. The ionization region was doped with hexachloroethane to suppress interferences. 4-Nitrobenzonitrile was used to calibrate the instrument. The desorption and inlet temperatures were 270°C, and the buffer gas temperature was controlled at 115°C. The airflow was 400 mL/min with a shutter grid opening time of 0.2 ms and a scan period of 30 ms. The sample was desorbed into the IMS for 30 s. Figure 15.2 shows the results of a standard, blank, and sample for the determination of parabens by SPME-IMS. 

The dehydrating action of cyanuric chloride on benzamide was known [60] in 1886 but its efficacy in converting aldoximes to nitriles under mild conditions was only recently demonstrated [61]. The chloride and an oxime in pyridine at room temperature gave benzonitrile (82%), 4-nitrobenzonitrile (92%) or 2-cy-anopyridine (63%). An 0-triazine intermediate may be involved ... 

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