Friedel–Crafts acylations of aromatic hydrocarbons. Part XI. The acetylation and benzoylation of 2,6-dimethylnaphthalene

Abstract

The Friedel–Crafts acetylation or benzoylation of 2,6-dimethylnaphthalene gives mainly 1-acetyl-3,7-dimethylnaphthalene or 1-benzoyl-2,6-dimethylnaphthalene, respectively. Smaller amounts of the other isomers are also formed. Diacetylation affords mixtures of 1,5-diacetyl-2,6-dimethylnaphthalene and 1,5-diacetyl-3,7-dimethylnaphthalene. Competitive acetylation of 2,6-dimethylnaphthalene and naphthalene in chloroform solution gives the following positional reactivities: 1-naphthyl 1·00, 2-naphthyl 0·31, 2,6-dimethyl-1-naphthyl 4·1, 3,7-dimethyl-1-naphthyl 8·1, 3,7-dimethyl-2-naphthyl 0·045; the values for the corresponding benzoylation are 1·00, 0·40, 260, 116, and 12, respectively.