Smooth Metal‐Free Photoinduced Preparation of Valuable 8‐Arylxanthines

Abstract

A set of 8‐arylxanthines was prepared under metal‐free conditions and in aqueous solvents from arylazo sulfones and caffeine or theophylline. Notably, the process took place by simply exposing the reaction vessel to visible or solar light, and unreacted xanthine could be easily recovered during the purification step.