Design of antineoplastic agents based on the "2-phenylnaphthalene-type" structural pattern. 4. Synthesis and biological activity of 2-chloro-3-(substituted phenoxy)-1,4-naphthoquinones and related 5,8-dihydroxy-l,4-naphthoquinones

The intermediate in the preparation of 1,3,7,10-tetrahydroxybenzo[b]naphtho[2,3-d]furan-6,11-dione (2), 2-chloro-5,8-dimethoxy-3-(3,5-dimethoxyphenoxy)-1,4-naphthoquinone (8h), and corresponding hydroxyl, methoxyl, and acetoxyl analogues was found to possess interesting inhibitory activities in a number of cytotoxic test systems. Activities were also noticed in some 5,8-dihydroxy-1,4-naphthoquinone derivatives. A structure-activity discussion of compounds of this series is presented. The newly uncovered biological activity of 2-chloro-3-(substituted phenoxyl)-1,4-naphthoquinones and 2,3-bis(substituted phenoxy)-1,4-naphthoquinones may suggest an approach for the development of new classes of antineoplastic agents.