Friedel–Crafts acylations of aromatic hydrocarbons. Part XII. Acetylation and benzoylation of 1,4-dimethylnaphthalene and 1,2,3,4-tetramethylnaphthalene

Abstract

The Friedel–Crafts acetylation of 1,4-dimethylnaphthalene gives mixtures of 2- and 6-acetyl derivatives, the proportions of which vary according to the experimental conditions. The corresponding benzoylation gives mainly the 2-benzoyl compound. No 5-acylation occurs. Acylation of 1,2,3,4-tetramethylnaphthalene gives 6-acyl derivatives. Competitive acetylation experiments in chloroform solution give the following positional reactivities: 2-naphthyl 1·00, 1,4-dimethyl-2-naphthyl 12·8, 1,4-dimethyl-6-naphthyl 3·4, 1,2,3,4-tetramethyl-6-naphthyl 141; the values for the corresponding benzoylations are 1·00, 79, 10·9, and 490, respectively.