Nucleophilic aromatic addition: I. The reaction of diazomethane with 1,3,5‐trinitrobenzene

Abstract

The structure of the reaction product from 1,3,5‐trinitrobenzene and an excess (i.e. at least four moles) of diazomethane, as found many years ago by Heinke, is shown to be a seven‐membered ring‐compound condensed with two cyclopropane rings and with one pyrazoline ring (VII). If 1,3,5‐trinitrobenzene is treated with diazomethane in a molar ratio of 1:3, no pyrazoline derivative is formed, but a hitherto unknown “tris‐methylene” derivative (VI), containing a seven‐membered ring system condensed with two cyclopropane rings. This remarkably stable compound is an intermediate in the reaction with excess of diazomethane. When the molar ratio of the reactants is reduced to 1 : 2 or 1 : 1, the “trismethylene” derivative (VI) results, together with unchanged 1,3,5‐trinitrobenzene.