Nitration of anisole

The nitration of anisole in 40% aq. nitric acid in the presence of some nitrous acid yielded 2,4-dinitrophenol as the main product. In more concentrated solutions of nitric acid 0- and />-nitroanisoles were the main products, less than o-1 % of the weta-isomer being formed. " The isomeric ratios for nitration imder a variety of conditions are given later ( 5.3.4). 

The kinetics of nitration of anisole in solutions of nitric acid in acetic acid were complicated, for both autocatalysis and autoretardation could be observed under suitable conditions. However, it was concluded from these results that two mechanisms of nitration were operating, namely the general mechanism involving the nitronium ion and the reaction catalysed by nitrous acid. It was not possible to isolate these mechanisms completely, although by varying the conditions either could be made dominant. 

It was shown that in preparative experiments sulphuric acid markedly catalysed, and acetate ions markedly anticatalysed the nitration of anisole. ... 

Kinetic studies have been made on the nitration of anisole, 4-chloroanisole, 4-nitrophenol and mesitylene105. For anisole the kinetics are complicated by demethylation for 4-chloroanisole, nitration by 4-10 M nitric acid in glacial... 

Samajdar et al. (2000) performed nitration of aromatic compounds by bismnth nitrate on catalysis with montmorillonite KSF. The reaction develops in THF suspension on steering dnring 10 min. Nitration of anisole proceeds strictly in the para position (91% yield after 10 min), bnt in case of phenol, the reaction occnrs to be nonregioselective and 3 1 mixture of para and ortho nitro prod-nets is formed with a common yield of 89%. Nitration of estrone (the steroid phenol) also leads to 1 1 mixtnre of para and ortho nitrophenolic steroids in 94% yield. 

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. 

TNAns is hygroscopic and is decompd by hot water with the formation of iso-picric acid (qv) (Ref 26). TNAns was prepd in 1849 by Cahours by direct nitration of anisole (Ref 6). This method according to Davis (Ref 51) is dangerous as it may produce an... 

The effects of added species. The rate of nitration of benzene, according to a rate law kinetically of the first order in the concentration of aromatic, was reduced by sodium nitrate, a concentration of io 3 mol l-1 of the latter retarding nitration by a factor of about 4.llc>28 Lithium nitrate anticatalysed the nitration and acetoxylation of o-xylene in solutions of acetyl nitrate in acetic anhydride. The presence of 6 x io-4 mol 1 1 of nitrate reduced the rate by a factor of 4, and modified the kinetic form of the nitration from a zeroth-order dependence on the concentration of aromatic towards a first-order dependence. However, the ratio of acetoxylation to nitration remained constant.146 Small concentrations of sodium nitrate similarly depressed the rate of nitration of anisole and again modified the reaction away from zeroth to first-order dependence on the concentration of the aromatic.116... 

Trinitroanisole was first obtained by Cahours [2a] by the direct nitration of anisole. The reaction proceeds very vigorously, as file presence of a methoxy group greatly facilitates the introduction of nitro groups and some highly coloured by-products are formed [20]. For this reason it is preferable to prepare trinitroanisole via chlo-rodinitrobenzene (p. 547). 

Beil 6, 138, (79) [l39l Anisole,Azidoderivotives. See Azidoanisole and Derivatives under Azides, Organic Nitration of Anisole has been discussed in many papers such as ... 

Example 1.9. Write resonance forms for the intermediate in the nitration of anisole at the para position. 

Because the nitro group is attached to an sp -hybridized carbon, it is not conjugated with the electrons in the ring and is not important to their delocalization. Thus, if resonance forms were being written to rationalize the stability of the intermediate in the nitration of anisole, the detail in the nitro groups would not be important because it does not contribute to the stabilization of the carbocation intermediate. 

Nitroanisois. Nitration of anisol to o- and p-nitroanisoi was studied by Schofield and co-workers [901. Mononiiration in 54 sulphuric acid at 25 ( gave the ratio o/p = 1.8 0.7. 

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