Nitrobenzyl Cyanide

In a 2-1. round-bottom flask, fitted with a stopper holding a dropping funnel and a mechanical stirrer, is placed a mixture of 275 cc. of concentrated nitric acid (sp. gr. 1.42) and 275 cc. of concentrated sulfuric acid (sp. gr. 1.84). This is cooled to io° in a freezing mixture, and 100 g. of benzyl cyanide (free from alcohol and water) are rim in slowly, at such a rate that the temperature remains at about io° and does not exceed 20°. After all the benzyl cyanide has been added (about one hour), the ice bath is removed, the mixture is stirred for an hour and then poured on to 1200 g. of crushed ice. A pasty mass slowly separates more than half of this mass is / -nitrobenzyl cyanide, the other constituents being o-nitrobenzyl cyanide, and a variable amount of an oil which resists hydrolysis apparently no dinitro compounds are formed. The mass is filtered on a porcelain funnel with suction, pressed well to remove as much oil as possible, and dissolved in 500 cc. of boiling alcohol (95 per cent). On cooling, -nitrobenzyl cyanide crystallizes the mother liquor, on distillation, gives an impure alcohol which can be used for the next run. Recrystallization from 550 cc. of 80 per cent alcohol (sp. gr. 0.86 to 0.87) yields 70 to 75 g. (50-54 per cent) of a product which melts at 115-1160. 

This product is satisfactory for most purposes, and incidentally for the preparation of -nitrophenylacetic acid. Occa- 

Fuming nitric acid may be used in nitrating benzyl cyanide, but the method here described is cheaper. 

The yield of 70 g. is obtained from benzyl cyanide, which boils over a 50 range prepared as described in preparation III (p. 9). Very pure benzyl cyanide will give a slightly higher yield, while commercial grades may give only 50 g, of p-nitro-benzyl cyanide and much oil. 

The reaction has been also carried out with 500 g. of benzyl cyanide. Under these conditions a 5-I. flask was used, and it required two and a half hours to add the benzyl cyanide. The yield of product was 325 to 370 g. 

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In Scheme 1.15, path c is sometimes a feasible process. Thus, for the anion-radical derived from 4-nitrobenzyl cyanide, path c is favored over paths a and b by 84 and 150 kJ mol , respectively. Typical examples of anion-radical deprotonation are the reactions in Scheme 1.18 (Zhao and Bordwell 1996a). It is path c of Scheme 1.15 that describes the acidity of anion-radicals. 

Mononitrobenzyl Cyanide, 02N.CeH4.CH2.CN mw 162.14, N 17.28%. Three isomers 2-,3 and 4 Nitrobenzyl Cyanides are described in Beil... 

Nitroanisoles, m81, m82 4-Nitrobenzyl cyanide, n65 Nitrocresols, m323, m324... 

Other Names Acetonitrile, (p-nitrophenyl)- (p-Nitrophenyl)acetonitrile 4-Nitrobenzeneacetoni-trile 4-Nitrobenzyl cyanide 4-Nitrophenylacetonitrile NSC 5396 p-Nitro-a-tolunitrile p-Nitro-benzeneacetonitrile p-Nitrobenzyl cyanide CA Index Name Benzeneacetonitrile, 4-nitro-CAS Registry Number 555-21-5 Merck Index Number 6591 Chemical Structure... 

Kahr, A. Mualem, R. One-step synthesis of 2- and 4-nitrobenzyl cyanides. Synthesis 1987, 514—515. 

It is satisfactory to find that the large value of k /k found for the reaction of 2-nitropropane with 2,4,6-trimethylpyridine is accompanied by large values of E — E (3.0 kcal mol" ) and A jA (about 7), though these values are subject to some uncertainty. Similarly, the reaction of 4-nitrobenzyl cyanide, which exhibits deviations from the Arrhenius equation at low temperatures, also gives the high values E — E = 1.85 0.2 kcal mol" aMa 5. The correspondence between two criteria for the same reaction increases our confidence that the explanation in terms of the tunnel correction is the right one. 

Dicbloronitrobenzene o-Nitrobenzyl chloride m-Nitrobenzyl chloride p-Nitrobenzyl chloride o-Nitrobenzyl bromide m-Nitrobenzyl bromide p-Nitrobenzyl bromide o-Nitrobenzyl iodide m-Nitrobenzyl iodide p-Nitrobenzyl iodide o-Nitrobenzyl cyanide... 

Nitrobenzyl cyanide has hitherto been prepared by the action of fuming nitric acid1 on benzyl cyanide. 

In making experiments with 500 g. of />-nitrobenzyl cyanide, it was found that the time for hydrolysis was about the same as when smaller amounts were used. 

In a i-l. round-bottom flask are placed too g. of -nitrobenzyl cyanide. A solution of 300 cc. of concentrated sulfuric acid (sp. gr. 1.84) in 280 cc. of water is prepared, and two-thirds of this solution is poured on to the p-nitrobenzyl cyanide. The mixture is shaken well, until the solid is all moistened with the acid. Any solid material sticking to the walls of the vessel is now washed down into the liquid with the remainder of the acid, the flask is attached to a reflux condenser, then set, without shaking, over a 10-cm. hole in a large sheet of asbestos board which rests on a tripod, and heated until the mixture boils. The boiling is continued for fifteen minutes. 

The reaction mixture, which becomes rather dark, is diluted with an equal volume of cold water and cooled to 0° or below. The solution is filtered, the precipitate is washed several times with ice water and then dissolved in 1600 cc. of boiling water. (A few grams of animal charcoal are added in dissolving the precipitate, if a technical -nitrobenzyl cyanide has been used.) This solution is filtered as rapidly as possible through a large folded filter, preferably with a steam funnel. In spite of all precautions, however, some solid usually separates on the filter. This must be redissolved in a minimum quantity of boiling water, and this solution then filtered into the main solution. The... 

Nitrobeozyl alcohol, 882 m-Nitrobenzyl alcohol, 881 p-Nitrobenzyl bromide, 961 p-Nitrobenzyl cyanide, 751, 763 p-Nitrobenzyl esters, 362 ... 

Experimental details for the nitration of benzyl cyanide are also included (Expt 6.21). The product is largely p-nitrobenzyl cyanide (some of the ortho isomer is also formed) the cyanomethyl substituent (as a substituted alkyl group) is thus an ortho/para directing and weakly activating group. 

Place a mixture of 275 ml of concentrated nitric acid with an equal volume of concentrated sulphuric acid in a 2-litre three-necked flask, fitted with a thermometer, a mechanical stirrer and a dropping funnel and assembled in the fume cupboard. Cool the mixture to 10 °C in an ice bath, and run in 100 g (98 ml, 0.85 mol) of benzyl cyanide (Expt 5.157) at such a rate (about 1 hour) that the temperature remains at about 10°C and does not rise above 20 °C. Remove the ice bath, stir the mixture for 1 hour and pour it on to 1200g of crushed ice. A pasty mass slowly separates more than half of this is p-nitrobenzyl cyanide, the other components being the ortho isomeride and a variable amount of an oil. Filter the mass on a sintered glass funnel, press well to remove as much oil as possible and then dissolve in 500 ml of boiling rectified spirit. The p-nitrobenzyl cyanide crystallises on cooling. Filter this off at the pump and recrystallise from 80 per cent ethanol. The yield of p-nitrobenzyl cyanide, m.p. 115-116 °C, is 75 g (54%). Another recrystallisation raises the m.p. to 116-117°C. 

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