ARYLNAPHTHOQUINONES. 6. SYNTHESIS OF 3-ARYL-1,2-NAPHTHOQUINONES AND THEIR REACTIONS WITH 1,3-DICARBONYL COMPOUNDS

Анотація

3-Aryl-1,2-naphthoquinones 1–7 were synthesized with yields of 20–50% in the reactions
between diazonium salts and 1,2-naphthoquinone in aqueous formic acid solution at the presence of a
catalytic amount of copper(II) chloride.
The synthesized 3-aryl-1,2-naphthoquinones were studied in the reactions with cyclic and
non-cyclic β-dicarbonyl compounds and ketoesters. It was shown that the acetoacetic ester and
acetylacetone were easy added to the naphthoquinone’s double bond in anhydrous dioxane and zinc
chloride. Obtained 1,2-dihydroxynaphthalene derivatives were oxidized by concentrated nitric acid
without the isolation and identification into substituted 1,2-naphthoquinones 8–10.
The substituted 1,2-naphthoquinone 11 was obtained similary in the reaction of the
3-(4-chlorophenyl)-1,2-naphthoquinone 3 with 5,5-dimethylcyclohexane-1,3-dione with high yield.
The structures of compounds 1–11 were confirmed by elemental analysis data, and
additionally by 1 H NMR spectroscopy in case of 3, 6, 7, 11.

Key words: 1,2-naphthoquinone, 3-aryl-1,2-naphthoquinones, arylation, diazonium salts,
1,3-dicarbonyl compounds.