Synthesis of multi ring-fused 2-pyridones via an acyl-ketene imine cyclocondensation.
Polycyclic ring-fused 2-pyridones (5a-e and 9a-e) have been prepared via a microwave-assisted acyl-ketene imine cyclocondensation. Starting from 3,4-dihydroisoquinolines (4a-b) or 3,4-dihydroharman (8), fused 2-pyridones could be prepared in a one-step procedure. By using either Meldrum's acid derivatives (1a-d) or 1,3-dioxine-4-ones (7a-b) as acyl-ketene sources, mono- or disubstitution of the fused 2-pyridone ring could be accomplished. As an application of the method, a formal synthesis of the indole alkaloid sempervilam was performed.
Pemberton
Nils
N
Organic Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
Jakobsson
Lotta
L
Almqvist
Fredrik
F