Synthesis and Cytotoxicity of 9‐Substituted Benzo[ de ]chromene‐7,8‐dione and 5‐Benzyl‐9‐substituted Benzo[ de ]chromene‐7,8‐dione

New Mansonone analogues of 9-substitued benzo[ de] chromene-7,8-dione 5b-e and 5-benzyl-9-substitued benzo[ de] chromene-7,8-dione 6a-e were prepared through a modified route. The first step involved a bulky base t-butylamine mediated regioselective deacetylation of 2-substituted-1,4-naphth-diyl diacetate, resulting in obtaining of monoacetate 4-acetate 2 in high yield. The mechanism of cyclization, debenzylation, and oxidation for the formation of 5a - e and 6a - e were discussed. The cytotoxicity of the prepared compounds 5 and 6 were comparable with naturally occurring Mansonone F.