Abstract The reactivity of 8-bromo-3, 9-dimethylxanthine (6) towards a variety of nucleophilic reagents has been investigated. Nucleophilic displacements take place easily with aliphatic mercaptans and aliphatic alcohols, whereas aliphatic amines required more severe conditions. Prolonged heating of 6 with amines causes a new type of rearrangement from 3, 9-to 3, 7-dimethylxanthines due to a 1, 3-sigmatropic shift of the N (9)-methyl group.
