Synthesis and acetylation of naphthols as precursors to naturally derived naphthoquinones; crystal structure of the aphin-related 7-O-methyl quinone A

Abstract

A route is described to 1,5,7-trialkoxy-4-naphthols. A method has been established to convert these compounds into the corresponding 3-acetyl-4-naphthols, in good yield, with a view to synthesizing naturally derived naphtho[2,3-c]pyran-5,10-quinones. Boron trichloride-induced monodemethylation of racemic Quinone A dimethyl ether was effected without perturbation of the pyran ring stereochemistry; this was confirmed by an X-ray crystallographic investigation.