Abstract
The reaction of 3-iodo-3,6-dialkyl-1,2-cyclohexanedione (2) with iodine–copper(II) acetate in acetic acid–water (5:1) at 80 °C gave the respective 3-hydroxy-2,5-dialkyl-1,4-benzoquinone in 38–80% yields. On the other hand, the reaction of 2 with copper(II) acetate in acetic acid–water (10:1) under refluxing afforded the respective 3,3′-dihydroxy 2,2′,5,5′-tetraalkyl-4,4′-diphenoquinone (5) in 41–85% yields. In the case of 3-bromo-3,6-dialkyl derivative (3) with copper(II) acetate, the diphenoquinone derivatives and 3-hydroxy-2,5-dialkyl-1,4-benzoquinone were obtained.