The Ring-A Aromatization of Estradiene Derivative

The Ring-A aromatization of 11β-hydroxyl or 11β-methoxyl estra-4,9-diene deriva- tives was studied.. It was found that these estradiene derivatives would give rise to estra-1,3,5(10), 9(11)-tetraens when treated with acidic catalyst in protonic solvents. A estra-4,9,11-Irene-3, 17-dione intermediate mechanism was suggested and partly confirmed by further investigation. The aromatization process can also be catalyzed by Iodine.