Irradiation of four 1-aryl-1, 2-propanediones (Ia–Id) with over 300 nm light in 2-propanol gives reduction products identified to be the corresponding pinacols or hydrols formed by the reduction at the aroyl (but not acetyl) oxygen. The products from 1-(o-tolyl)-1, 2- propanedione (Id) can also be accounted for by the initial hydrogen abstraction from ortho methyl by the aroyl carbonyl oxygen. Their photoreactivities are discussed as regards their ...
