Simple analogs of the toxin callicarpone

Callicarpone, a component 10 times as toxic to fish as rotenone, has been isolated from the leaves of Callicarpa candicans. It is reasonable to assume that callicarpone will act as an insecticidal agent as does rotenone. Therefore, the structure-activity relationship of callicarpone was examined by synthesizing a series of compounds having certain of its structural features. Those compounds were tested for insecticidal and antimicrobial activities. A study of synthetic analogs elucidated the functional group chemistry of callicarpone so that a synthesis might be undertaken. Piperitone oxide showed approximately 1/100th the activity of rotenone against Daphnia magna. 1-(alpha-Hydroxyisopropyl)-3-oxocyclohexene oxide showed activity against myobacterium while 2,3,4,6,7,8-hexahydronaphthalene-1,4-dione showed inhibitory activity against the mycobacterium and two yeasts.