合成路线1

Esterification of 1-naphthol (I) with 3-methylcrotonic acid chloride (II) provides ester (III), which subsequently rearranges to the hydroxy ketone (IV). Cyclization of (IV) under acidic conditions provides the tricyclic system (V). Keto group reduction in (V) by means of LiAlH4 leads to alcohol (VI), which upon acidic treatment is dehydrated to olefin (VII). Further catalytic hydrogenation of (VII) in the presence of Pd/C yields the dihydro naphthopyran (VIII). Electrophilic nitration of (VIII) provides (IX). After reduction of nitro derivative (IX) to the corresponding amine (X) by means of Sn/HCl, acylation with acetic anhydride furnishes acetamide (XI). Finally, oxidation of (XI) with concentrated nitric acid gives rise to the target ortho-quinone .