Reactions concerned in Tertiary Amine N-Oxides. XIII. Reactions of Benzo-[f, h and g] quinoline and Acridine with Aromatic Amine N-Oxides

Abstract

Dehydrogenative condensation of two molecules of pyridine 1-oxide or N-oxides of benzo [f] quinoline (I), benzo [h] quinoline (IV), benzo [g] quinoline (VIII), and acridine (XIII) by hydrogenation using a platinized palladium-carbon catalyst affords respective dimers bonded at 2-position of the ring nitrogen, except in XIII which cannot undergo dehydrogenation at 2-position of the ring nitrogen. I and IV also afforded the corresponding pyridylbenzoquinoline, although in a small quantity. Dimerization of these compounds is extremely poor compared to pyridine and quinoline. IV formed its dimer only when 10-hydroxybenzo [h] quinoline was reacted as its N-oxide. VIII was synthesized by dehydrogenative aromatization of 6, 7, 8, 9-tetrahydrobenzo [g] quinoline with DDQ and VIII was not formed when palladium-carbon was used, resulting in the formation of a dimer.