SYNTHESIS OF ACETYLCARBONYLNAPHTHAZARINES AND METHOXYCARBONYLNAPHTHAZARINES

A variety of 1,4-diacetoxy-5,8-dihydronaphthalene derivatives 14-20 we re prepared in high yields by treatment of the respectives adducts 6-1 2 with Ac2O and Ac2O-pyridine. Oxidation of 16 and 19 with chromiun (V I) oxide afforded the aromatization products 21 and 27 in low yields. Oxidation of 17 with chromiun oxide followed by hydrolysis gave naphth azarin 22a. Naphthazarines 26a and 31a were prepared from the respecti ves diacetates 18 y 19 by oxidation followed by hydrolysis. On the bas is of the structure of 7-acetyl-6-chloro-2-methylnaphthazarin 36a and 2,3-dichloronaphthazarin diacetate 40, prepared via the corresponding acetates 35 and 39, the structure of naphthazarines 22, 26 and 31 are proposed.