Dye-sensitized photooxygenation of tyrptophan: 3a-Hydroperoxypyrroloindole as a labile precursor of formylkynurenine.

Abstract

The isolation, structure determination, and reactivity of the tricyclic labile hydroperoxides 10 and 2 obtained by dye-sensitized photooxygenation of L-, D-, and DL-tryptophan and Nb-methoxycarbonyltryptophan ester are reported. The tricyclic hydroperoxide 10, under appropriate conditions, was easily convertible to formylkynurenine. Plausible mechanisms for these transformations are discussed.