STUDIES ON QUINONES .23. SYNTHESIS OF AZEPINONES FUSED TO QUINONE SYSTEMS

The Diels-Alder reactions of 3,4-dihydro-5H-1-benzazepine-2,6,9-trione 1 with butadiene, cyclopentadiene, 1-(E)-trimethylsiloxybutadiene 4, and methacrolein dimethylhydrazone are described. Cycloaddition with the unsymmetrical dienes 4 and 18 occurs regiospecifically affording 5 and 19 respectively. The structure of 5 was established through naphthazepine 13 by comparison of its H-1 nmr with model compounds. The probable course of cycloaddition with 1-azadiene 18 is analyzed considering the polarization of azadiene 18 and the behavior of quinone 1 in the reaction with 4. Michael addition of quinone 1 with isobutenylmorpholine 23 which afforded exclusively the cyclic O,N-acetal 24 or 25 and its convertion to benzepinquinone 26 or 27 is also reported.