A mild and efficient route to 2-benzyl tryptamine derivatives via ring-opening of β-carbolines

We described a mild and easy method, in two steps, by which various benzyl groups were introduced in the C-2 position of tryptamine. The first step consisted on the synthesis of β-carbolines, starting from tryptamine derivatives, by a Pictet–Spengler reaction. Ring-opening of the β-carbolines, by hydrogenation, led to the desired 2-substituted benzyl tryptamine indole products. A supplementary step of alkylation could be realized to give N-alkyl-2-substituted benzyl tryptamine. During these reactions, nitrogen atoms require no step of protection.