Oxygenation of indoles by a copper(I) chloride pyridine complex. A new tryptophan 2,3-dioxygenase model system

The copper(I) chloride, pyridine system has shown marked tryptophan 2,3-dioxygenase activity with tryptophan and indole derivatives. However, only in the cases of tryptophan and 3-methylindole was it possible to isolate the primary products N-formylkynurenine (approximately 1%) and 2-formamidoacetophenone (70%), respectively. In other cases, such as 2-methylindole, methyl indole-3-acetate, tryptamine, indole-3-propionic acid, and acetyltryptophan methyl ester, only secundary products could be isolated or determined by GC-MS methods.