Synthetic studies of sesquiterpenes with a cis-fused decalin system, 5. A synthetic approach to the study of structure-activity relationships of the termiticidal norsesquiterpenoids, chamaecynone and related compounds.

Various analogues of chamaecynone [1] were prepared from alpha-santonin, and the termiticidal activity of these compounds was examined. All compounds possessing a 5 beta H-13-noreudesmane skeleton with a ethynyl group at C-7 showed significant termiticidal activity. Changes in the structure of the A-ring of these compounds also influenced the potency of their termiticidal activity.