A NEW SESQUITERPENE KETO–LACTONE FROMSENECIO

A new sesquiterpene lactone (C 16 H 22 O 4 , m. p. 235–8, [α] 29 D – 94.5°) was isolated from Senecio aegyptius. The new lactone was proved by chemical and spectral means to have a γ–lactone ring structure, a secondary hydroxyl group, a ketonic carbonyl and a terminal méthylène group conjugated with the lactone. The acetyl derivative and the oxime were prepared and some physical and chemical data are given for them.