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NITRO DERIVATIVES OF BENZENE 251

The problem was finally solved by Meisenheimer [40] in 1902, who found that

by the addition of CH 3 OK to trinitrobenzene an anisole derivative was formed:

(9)

According to Meisenheimer, this formula was confirmed by the fact that the

product of the addition of potassium ethoxide to trinitroanisole is identical to the

product of the addition of potassium methoxide to trinitrophenetole. Meisen-

heimer’s view was later confirmed by a number of workers, as for example Busch

and Kogel [41], Bölian [42] and others (p. 203).

The reaction proceeds differently when sym-trinitrobenzene is heated with

sodium ethoxide. One of the nitro groups is substituted by a methoxy or ethoxy

group, 3,5-dinitroanisole or 3,5-dinitrophenetole being formed:

(10a)

+ NaNO 2 (Blanksma [43])

(10b)

Similarly, when trinitrobenzene is boiled with an aqueous solution of NaOH,

sodium 3,5-dinitrophenate is formed along with some tetranitroazoxybenzene

(de Bruyn [16]):

At a low temperature sym-trinitrobenzene may form an addition product with

NaOH (Giua [15]). Giua ascribed to it a structure based on Meisenheimer’s proposals :