A sesquiterpene lactone fromAcroptilon repens

A new sesquiterpene lactone has been isolated from the epigeal part ofAcroptilon repens, with the composition C₁₉H₂₂O₆, mp 199–201°C, M⁺ 346, and it has been called acroptin (I). The treatment of (I) with acetic anhydride in pyridine gave a diacetate (II). The structure of (I) has been confirmed by the NMR spectra of (I) and (II). Details of the IR and NMR spectra of (I) and (II) are presented.