2-Nitroanisole

First of all, there are the two products of O-coupling addition of methoxide ion to the diazonium ion, the (Z)- and (jE)-diazo methyl ethers. As discussed in Section 6.2, they are formed in reversible reactions with half-lives of the order of a fraction of a second (Z) to a minute (E). The two diazo ethers are, however, decomposed rapidly to the final dediazoniation products. We show in Scheme 8-47 the products obtained by Broxton and McLeish (1983 b) in the dediazoniation of 4-chloro-3-nitrobenzenedi-azonium ion (8.64) with methoxide ion in CH3OH. The products are 4-chloro-3-nitro-anisole (8.65, 49 9o), 2-chloro-nitrobenzene (8.66, 449o), and 2-nitroanisole (8.67). 

The level of deuteration found in the third product, 2-nitroanisole (8.67), is also consistent with these two pathways of hydro-de-diazoniation, but preceded in this case by a methoxy-de-chlorination. 

Kinetic studies of molecular bromination have been carried out using a variety of solvents other than acetic acid. The bromination of 2-nitroanisole by bromine in water revealed that molecular bromine is the reactive species and that the tribromide ion is very unreactive191. By making allowance for the concentration of free bromine (which differs from the stoichiometric concentration through reaction with bromine ion), good second-order rate coefficients were obtained by application of equation (133) with k2 = 0.062 at 25 °C the dominance of the bimolecular mechanism is to be expected here in view of the trend observed on making acetic acid media more aqueous. 

A very large scale reaction to produce 2-nitroanisole from chloronitrobenzene and methanolic sodium hydroxide ran out of control and painted the town orange. This was attributed to reduction of the nitro group at temperatures above 100°C, a far more exothermic reaction than intended. This temperature was reached because the methanolic alkali was charged without agitation, and, the reaction not starting, the batch was heated to 90°C. The agitation was only then switched on. 

A calorimetric study of reaction with sodium or potassium hydroxides in ethanol or 2-propanol is given. At starting temperatures below 70°C the product is the appropriate nitrophenyl ether above that temperature, reduction of the nitro groups may come into play, to give much more energy and a variety of other products. This reaction is inhibited by oxygen. There is potential for runaway if such reactions are operated industrially with poor temperature control. The editor suspects that the stimulus for this study was an accident which sprayed the German environment with 2-nitroanisole. 

In the preparation of 2.2 -dimcthoxvazoxybenzcnc. solvent ethanol was distilled out of the mixture of 2-nitroanisole, zinc and sodium hydroxide before reaction was complete. The exothermic reaction continued unmoderated, and finally exploded. 

Nitroanisole, Sodium hydroxide See 2-Nitroanisole Sodium hydroxide, etc. 

The loss of isobaric neutral species from the molecular ions of isomeric nitroanisoles has been studied using deuterium labelling74. The mass analysis indicated that specific loss of CH2O occurs from the molecular ions of 2-nitroanisole, while a specific loss of NO takes place from 3-nitroanisole74. Although the peak due to [M —NO]+ is neglectible in the MS of 2-nitroanisole, it is apparently an important transient intermediate in the consecutive fragmentation of the molecular ions. 

Dinitrotoluene, Sodium oxide, 2726 Lithium 4-nitrothiophenoxide, 2177 4-Methyl-2-nitrophenol, 2767 2-Nitroanisole, Sodium hydroxide, Zinc, 2768 Nitrobenzene, Alkali, 2262... 

Careful nitration of anisole (CH3OC6H5) with a new nitrating reagent gives a mixture of 4-nitroanisole and 2-nitroanisole. The section of the NMR spectrum below is from the aromatic region of the crude reaction mixture which is a mixture of the 4- and 2-nitroanisoles. Determine the relative amounts of the two products in the reaction mixture from the integrals in the spectrum. 

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