Abstract The reactivity of hydroxy-indoles under the conditions of the Mannich-reaction has been studied. The electrophilic side-chain enters in each case in a position ortho to the phenolic group. 4-Hydroxy-indole is substituted in the 5-, 5-hydroxy-indole in the 4-, 6- hydroxy-indole in the 7-, and 7-hydroxy-indole probably in the 6-position. The structures of the Mannich bases from 4-, 5-and 6-hydroxy-indole have been confirmed by comparison ...
