Synthesis of Diazonaphthoquinones from Naphthols by Diazo-Transfer Reaction

Abstract Various orthodiazonaphthoquinones (1-diazo-2(1H)-naphthalenones and 2-diazo-1(2H)-naphthalenones) were synthesized using the diazo-transfer reaction between the appropriate naphthol and 2-azido-1,3-dimethylimidazolinium chloride (ADMC). The ADMC was prepared by the reaction between 2-chloro-1,3-dimethylimidazolinium chloride and sodium azide. The diazo-transfer reaction selectively introduced the diazo group at the C(2) position of 1-naphthol or the C(1) position of 2-naphthol. The naphthalenediols that were tested, except for 1,3-naphthalenediol, also reacted with ADMC to afford the corresponding monodiazotized compound. X-ray analyses suggested that the diazonaphthoquinones did not have diazoniumnaphtholate structures but had diazocarbonyl structures.