Syntheses of 3-Azaacenaphthene and Its Derivatives

The syntheses of 3-azaacenaphthene (1), the compound which has an ethylene bridged ring at the 1 and 8-positions of isoquinoline, and its derivatives were studied. Ethyl 3, 4-dihydroisoquinoline1-acetate (5) was converted to the hydrochloride of 1, 2, 3, 4-tetrahydroisoquinoline-1acetic acid (9), then to 2 a, 3, 4, 5-tetrahydro-1-oxo-3-azaacenaphthene (10). Three methods were applied to a transformation of (10) to (1). During the$e synthetic processes, 2 a, 3, 4, 5-tetrahydro-3-azaacenaphthene (2) was also prepared.