Synthesis of 2-Acetyl-1,4-Dimethoxynaphthalene, A Potential Intermediate for Disubstituted Naphtho[2,3,c]pyran-5,10-dione

Abstract

2-Acetyl-1-hydroxynaphthalene was converted into the title compound in three steps (bromination, substitution and methylation). 1-Methoxynaphthalene on bromination, substitution and acetylation, respectively, also yielded the target compound.

First Synthesis of 1,4-Dimethoxy-2-Naphthoxyacetic acid

“…As the overall yield of the acid 5 was not satisfactory, an alternative route was sought and this is delineated in Scheme 2. The already known 1-methoxy-2-hydroxynaphthalene 6[5b] on bromination [5c] afforded compound 7 in 95% yield; this was converted into the naphthol 4 in 98% yield by the reported procedure [1]. The present method is simpler than that reported [3b].…”

“…2-Acetyl-1,4-dimethoxynaphthalene has proved to be a potential intermediate in the synthesis of 1,3-disubstituted and 1,1,3trisubstituted naphtha [2,3-c]pyran-5,10-diones, which are naturally occurring compounds that exhibit antimicrobial, antiparasitic and phytototoxic activities [1]. 2-Hydroxy-1,4-dimethoxynaphthalene has been utilized for the synthesis of Rhinacanthin A, a naphthoquinone that exhibits a wide range of biological activities [2].…”