Dye-sensitized photooxidation of some substituted 1,3-Diphenyl-2-pyrazolines

Abstract

1,3-Diphenyl-2-pyrazolines substituted in the 4- and 5-positions with phenyl groups undergo dye-sensitized photooxidation at widely different rates depending on the substitution pattern. Depending on both the solvent and the substitution pattern, two types of reaction are usually observed: (a) dehydrogenation to the corresponding pyrazole and (b) incorporation of oxygen with ring opening to yield carbonyl compounds.