A versatile synthesis of 3-substituted 4-cyano-1,2,3,4-tetrahydro-1-oxo- β-carbolines
Huber K., Kast O., Bracher F.
In a project aimed at the synthesis of analogues of the cytotoxic -carboline alkaloid bauerine C with more advantageous solubility properties, a 3-amino analogue was prepared by treating ethyl 3-(cyanomethyl)indole-2- carboxylate with ammonia. Upon addition of aldehydes or ketones to the reaction mixture, 3-substituted 4-cyano-1,2,3,4-tetrahydro-1-oxo - carbolines were obtained in a one-pot condensation. When cyclic ketones are used, the procedure allows a convenient synthesis of tetracyclic spiro compounds. © Georg Thieme Verlag Stuttgart · New York.