The Fischer reaction is applied to the synthesis of 8‐substituted tetrahydro‐γ‐carbolines with electron‐donating or electron‐withdrawing groups, using catalytic or thermal methods. The reaction conditions must be varied according to the nature of the N 1 substituent of the piperidone. The best results are observed when a releasing group is present on the arylhydrazine and a benzyl substituent on the nitrogen of piperidone. Formation of carbolines with a withdrawing substituent is observed in soft acidic conditions; in others, reaction ended at the hydrazone level or did not evolve.
