Photoreduction of aromatic ketones by amines in aqueous and alcoholic solution

Abstract

Photolysis of fluorenone in an ethanolic solution of triethylamine and of benzophenone in aqueous and alcoholic solutions of isobutylamine and t-butylamine gave the radical-anion of the ketone which was, in each case, characterised by e.s.r. With fluorenone, the products included 9-hydroxyfluorene and 9,9′-bisfluorenyl-9,9′-diol. Photolysis of benzophenone in aqueous and alcoholic solutions of a number of aliphatic amines usually gave 1,1,2,2-tetraphenylethane-1,2-diol. 4-Phenylbenzophenone, and 2-acetylnaphthalene, on photolysis in ethanolic triethylamine, gave the corresponding diols. Fluorenone is thermally reduced by solutions of sodium isopropoxide in isopropyl alcohol to give its radical-anion which subsequently gives 9-hydroxyfluorene.