Synthesis of acenaphtho[1,2‐x]heterocycles and spiro[acenaphthylene 1‐isoxazoles]

Methyl (Z)‐(1,2‐dihydro‐2‐oxo‐1‐acenaphthylenylidene)acetate 1 gives with hydroxylamine the oximes 2 and the pyrrole derivative 4, whereas with hydrazines affords the pyridazinones 5 and 6. A pyridazine derivative 8 is also isolated from the reaction of (1,2‐dihydro‐2‐oxo‐1‐acenaphthylenylidene)acetone 7 with hydrazine hydrate. Reaction between the spiro‐derivative 9 and hydroxylamine hydrochloride gives oxime 10, whereas Wittig olefination of 9 with ylide 11 yields compound 12 which by reaction with 2,4,6‐trimethylbenzonitrile oxide (13) affords the dispiro‐derivatives 14. Finally from the reaction of acenaphthylene‐1,2‐quinone (17) with the bisylide 16 the acenaphtho[1,2‐c]thiophene (18) is formed.