P-Nitrobenzyl chloride

Bromobenzene, iodobenzene and benzyl chloride behave somewhat similarly. The />-nitro-derivatives of the first two compounds frequently crystallise out even before pouring into water p-nitrobenzyl chloride usually remains as an oil for several minutes before solidifying. 

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... 

A mechanism of this type permits substitution of certain aromatic and ahphatic nitro compounds by a variety of nucleophiles. These reactions were discovered as the result of efforts to explain the mechanistic basis for high-yield carbon alkylation of the 2-nitropropane anion by p-nitrobenzyl chloride. p-Nitrobenzyl bromide and iodide and benzyl halides that do not contain a nitro substituent give mainly the unstable oxygen alkylation product with this ambident anion ... 

Diethyl sodium phthalimidomalonate (Barger and Weichselbaum, Organic Syntheses, 1943, Coll. Vol. II, 3B4) (6.52 g) was dissolved in boiling methyl ethyl ketone (BO ml) and a solution of p-nitrobenzyl chloride (3.44 g 1.0 mol) in the same solvent (20 ml) was added. Sodium iodide (ca 0.5 g) dissolved in hot methyl ethyl ketone (10 ml) was introduced, and produced an immediate precipitation. The mixture was refluxed for 1.5 hours, cooled, filtered, evaporated under vacuum and the residual gum crystallized from ethanol. The di-ethyl-p-nitrobenzyl-phthalimidomalonate formed colorless prisms (B8%), MP 103° to 105°C, sharpening to 104° to 105°C on recrystallizing from ethanol. 

The ability of a nitro group in the substrate to bring about electron-transfer free radical chain nucleophilic substitution (SrnI) at a saturated carbon atom is well documented.39 Such electron transfer reactions are one of the characteristic features of nitro compounds. Komblum and Russell have established the SrnI reaction independently the details of the early history have been well reviewed by them.39 The reaction of p-nitrobenzyl chloride with a salt of nitroalkane is in sharp contrast to the general behavior of the alkylation of the carbanions derived from nitroalkanes here, carbon alkylation is predominant. The carbon alkylation process proceeds via a chain reaction involving anion radicals and free radicals, as shown in Eq. 5.24 and Scheme... 

Kinetics and Mechanism of Reactions of Bis (methyl-2,2 -dimercaptodiethyl-amine) dinickel(II) with Alkyl Halides. The rates of reaction of [Ni2 CH3N-(CH2CH2S)2 2], structure III, with methyl iodide, benzyl bromide, benzyl chloride, p-chlorobenzyl chloride, and p-nitrobenzyl chloride have been studied as functions of temperature and concentration in chloroform (3). Absorbance measurements were utilized to determine the rates. All experiments were conducted with excess alkyl halide (20 to 1000 times the initial concentration of complex). Jicha and Busch (18) were able to isolate alkylated complexes of the composition... 

All data obtained on the rate of reaction of [Ni(NiL2)2]Cl2 with alkyl halides— i.e., methyl iodide, benzyl bromide, benzyl chloride, p-nitrobenzyl chloride, p-chlorobenzyl chloride, ethyl bromide, ethyl iodide, n-propyl bromide, and n-propyl iodide—conform closely to a pseudo-first-order rate law. Almost all experiments were carried out in the presence of an excess of alkyl halide. Since methanol solutions of the alkylated complexes have only negligible absorption at 495 m//, rates were obtained by graphs of log A0—A vs. time. The graphs are linear over the entire time interval, which corresponds to more than two half lives in most cases, passing through the origin at zero time. The rate is essentially the same whether measured by the spectrophotometric or conductivity method. 

Norrish and Smith f have studied two reactions, namely, the interactions of trimethylamine with m- and with p-nitrobenzyl chloride in non-polar solvents, with a view to correlating the absolute rates of change with the values for the energy of activation as calculated from the temperature coefficients. They find here also that there is a marked deactivating effect of the solvent, which, as they point out, is not surprising, since in solution the mean free path is of the same order as the molecular diameter, and nearly every collision between potentially reactant solute molecules must therefore of necessity partake of the nature of a ternary collision at least, in which the third body is a solvent molecule . 

Benzyl chloride and potassium selenocyanate give benzyl selenocyanate, which yields a para-compound on nitration, the latter also being obtained by the condensation of p-nitrobenzyl chloride with potassium selenocyanate. The strength of the nitric acid and the conditions of the nitration determine the resulting products in the case of chlorophenyl and tolyl compounds. Nitric acid (density 1 4) at 8° C. converts p-tolyl selenocyanate into di-2-nitro-p-tolyl diselenide and 2-nitro-p-tolylselenimc acid, whereas acid of density 1 5 at -10° C. yields 2-nitro-p-tolyl selenocyanate and a small amount of 3-nitro-p-tolyl selenocyanate. 

Cognate preparations. p-Nitrobenzaldehyde. This preparation is an example of the Sommelet reaction in which the hexaminium salt is isolated. Dissolve llg (0.13mol) of hexamethylenetetramine in 70ml of chloroform (CAUTION) and add 11.4 g (0.067 mol) of p-nitrobenzyl chloride or 14.4 g of p-nitrobenzyl bromide (Expt 6.28). Heat the mixture under reflux on a steam bath for 4 hours a precipitate gradually separates. Replace the reflux condenser by a condenser set for distillation and distil off about 35 ml of solvent. Add 35 ml of acetone, cool in ice, collect the precipitate by suction filtration and dry it in the air. Heat the hexaminium salt thus obtained under reflux for 1 hour with 100 ml of 50 per cent acetic acid then add 100 ml of water and 25 ml of concentrated hydrochloric acid and continue the refluxing for 5-10 minutes. Cool the solution in ice, collect the crystals of p-nitrobenzaldehyde and dry them in a vacuum desiccator. The yield is 6.4 g (63%), m.p. 106 °C. The p.m.r. spectrum is noted in Expt 6.117. 

W. S. Reich [96] prepared aromatic derivatives of trinitromethane (of the type IV) by acting with the silver salt of nitroform on ar-alkyl chlorides, as for example p- nitrobenzyl chloride ... 

A few nitro compounds have been obtained in good yields by the interaction of reactive halogen compounds with aci-nitro alkanes. The reaction is usually complicated in that both C- and 0-alkylation occurs. If the stability of the aci form of the nitro compound is high, then the tendency is toward alkylation on carbon rather than on oxygen. An example is the condensation of p-nitrobenzyl chloride with the sodium salt of nitro-ethane to give an 83% yield of 1-p-nitrobenzylnitroethane, P-OjNC.H CHjCHCNOjXIHj. ... 

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