Unexpected ipso-Substitutions at the β-Carboline Nucleus

Abstract

Minisci-type radical carbamoylation of 1-bromo-β-carboline (1) gives the 3-substituted product in low yield, whereas 1-acetyl-β-carboline (3a) reacts under ipso-substitution of the acetyl group. Cyanations of the N-oxides of 1 and 3a occur under clean ipso-substitution of the groups in 1-position. 1-Methyl derivatives show no tendency to react under ipso-substitution.

Keywords:

• β-Carbolines
• ipso-Substitution
• N-oxides
• Minisci reaction
• Cyanation

Acknowledgment

We thank the Fonds der Chemischen Industrie for financial support.