Oxidations with Lead Tetraacetate. I. Oxidations of Naphthalene Ethers

Abstract

Oxidations of 1- and 2-methoxy-, and 1,5- and 2,6-dimethoxy-naphthalene were performed thermally and photochemically with various oxidant/reactant ratios. A wide variety of products including acetoxy derivatives, dimers, o- and p-quinones (monomeric, dimeric and polymeric) and polysubstituted derivatives were formed demonstrating the high reactivity of naphthalene ethers. Higher ratios of oxidant gave increased yields of quinones, but photochemical reactions gave virtually the same mixtures of products as thermal processes. The position of the methoxy group controlled the initial attack by the reagent: for 1-methoxy- and 1,5-dimethoxy-naphthalene the 4-position is the site of reaction, while for 2-methoxy- and 2,6-dimethoxy-naphthalene position 1 reacts. Results indicate that initial products are further oxidized to the more complex structures found. Several different mechanistic paths are required to explain the variety of products.