Benzoyl nitrate

Benzoyl nitrate is also a good nitrating agent 

D Benzoyl nitrate and systems formed from nitric acid and acetic anhydride 

Acetyl nitrate, 0765 Benzoyl nitrate, 2689 Butyryl nitrate, 1573 3-Nitrobenzoyl nitrate, 2664 

Indole with benzoyl nitrate at low temperatures gives 3-nitroindole. More vigorous conditions can be used for the nitration of 2-methylindole because of its resistance to acid-catalyzed polymerization. In nitric acid alone it is converted into the 3-nitro derivative, but in a mixture of concentrated nitric and sulfuric acids 2-methyl-5-nitroindole is formed, by conjugate acid nitration (see section 3.3.3.2.1). 

Reactivity of benzoyl nitrate towards moisture is so great that attempted filtration through an undried filter paper causes explosive decomposition (possibly involving cellulose nitrate ). 

The nitrate explodes if heated rapidly, like benzoyl nitrate. 

Reaction of pyridine 1-oxide with benzoyl nitrate leads to the 3-nitro derivative the postulated mechanism is shown in Scheme 10. 

Thiophen-z-T acid, 25 °C (kinetic) Benzoyl nitrate—acetonitrile, 0-88 15 

Thiophene is nitrated by mild nitrating agents such as acetyl or benzoyl nitrate, mainly in the 

Ingold et al." showed that rates of nitration by benzoyl nitrate in carbon tetrachloride were depressed by the addition of benzoic anhydride. Thus addition of 0.035 M of the anhydride to a solution 2.36 M in benzene and 0.030 M in nitrate decreased the first-order rate coefficient from 44x 10-4 to 20xl0-4. This is consistent with nitration by dinitrogen pentoxide formed via equilibrium (37), viz. 

Nitrations in acetic anhydride, or in solutions containing benzoyl nitrate ( 5.2) or dinitrogen pentoxide ( 4.2.3) have long been associated with the formation from some aromatics of higher proportions of o-nitro-compounds than are formed under other conditions. 

The nitration of l,2,5-selenadiazolo[3,4-/] quinoline 77 with benzoyl nitrate affords the 8-nitro derivative 78, whereas methylation with methyl iodide or methyl sulfate afforded the corresponding 6-pyridinium methiodide 79 or methosulfate 80, respectively (Scheme 29). The pyridinium salt 80 was submitted to oxidation with potassium hexacyanoferrate and provided 7-oxo-6,7-dihydro derivative 81 or, by reaction of pyridinium salt 79 with phenylmagnesium bromide, the 7-phenyl-6,7-dihydro derivative 82. Nucleophilic substitution of the methiodide 79 with potassium cyanide resulted in the formation of 9-cyano-6,9-dihydroderivative 83, which can be oxidized by iodine to 9-cyano-l,2,5-selenadiazolo [3,4-/]quinoline methiodide 84. All the reactions proceeded in moderate yields (81IJC648). 

Thiophene is much more easily nitrated than benzene and it is therefore possible to use mild nitrating agents such as acetyl or benzoyl nitrate. Like pyrrole and furan the principal nitration product is the 2-derivative. The a selectivity decreases with increasing vigour of the reagent and up to 15% of the 3-isomer has been obtained. 

Dimethylpyridazine 1,2-dioxide gives the 4-nitro derivative in good yield with nitric acid, while with benzoyl nitrate the yield is considerably lower. 

Nitromesitylene has been prepared by the direct nitration of mesitylene with concentrated nitric acid/ and by the action of benzoyl nitrate on mesitylene in carbon tetrachloride at low temperature.  

Direct nitration of thiophene, using a mild nitrating system at low temperature, gives 2-nitrothiophene in excellent yield. Acetyl nitrate, benzoyl nitrate or copper(I) nitrate in acetic anhydride or acetic acid is commonly used, and only traces of 3-nitrothiophene and 2,5-dinitrothiophene are formed. Slow addition of thiophene dissolved in acetic anhydride to a solution of nitric acid in glacial acetic acid, maintaining the temperature at 10°C, is reported to be the optimum procedure (Section 3.14.2.4.8). 

These features serve to distinguish nitration in acetic anhydride from nitration in inert organic solvents. With other acyl nitrates less work has been done, and it is convenient to deal first with the case of benzoyl nitrate. 

Nitration of cinnoline 2-oxide takes a different course. With nitric and sulfuric acids or with potassium nitrate and sulfuric acid a mixture of 8-nitrocinnoline 2-oxide, 6-nitrocinno-line 2-oxide and 5-nitrocinnoline 2-oxide is obtained, while with benzoyl nitrate in chloroform only a low yield (1.5%) of the 5-nitro derivative is obtained. 

The kinetics of nitration of benzene in solutions at c. 20 °C in carbon tetrachloride have been investigated. In the presence of an excess of benzene (c. 2-4 mol 1 ) the rate was kinetically of the first order in the concentration of benzoyl nitrate. The rate of reaction was depressed by the addition of benzoic anhydride, provided that some benzoic acid was present. This result suggested that benzoyl nitrate itself was not responsible for the nitration, but generated dinitrogen pentoxide 

When nitration of pyridazine N-oxides is carried out with acyl nitrates (prepared in situ from acyl chlorides and silver nitrate) the reaction takes place at the /3-position relative to the N-oxide group. Under these circumstances only mononitro derivatives are formed. For example, nitration of pyridazine 1-oxide with acetyl nitrate yields 3-nitropyridazine 1-oxide (17%) and 5-nitropyridazine 1-oxide (0.8%), whereas with benzoyl nitrate a better yield of 5-nitropyridazine 1-oxide is obtained. 

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