Nitration of methoxybenzene

The nitration of methoxybenzene (anisole) proceeds 10,000 times faster than does nitration of benzene and produces predominantly the ortho and para isomers of ni-troanisole. 

Judgment must be exercised in cases where two of the general resonance criteria are in conflict. For example, the structure B is an important contributor to the resonance hybrid for the intermediate in the nitration of methoxybenzene (anisole), even though the structure has a positive charge on oxygen. This unfavorable feature is compensated for by the additional covalent bond present in structure B compared with the other major contributor, structure A, in which the positive charge is on carbon. 

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