Terpenoid constituents of Aster subspicatus and A. ageratoides.

Chemical investigation of the aerial parts of Aster subspicatus afforded a new sesquiterpene lactone, 8 alpha-acetoxy-1 alpha-hydroxy-3 alpha,4 alpha-epoxy-5 alpha,7 alpha H-9,11(13)-guaiadien-12,6 alpha-olide (1), in addition to the known compounds arteglasin-B (2), diversoside (3), and 2-phenylethyl beta-D-glucopyranoside. Re-investigation of Aster ageratoides afforded the known compounds crotocorylifuran, and oplopanone. The structure of the new compound was determined by spectroscopic methods particularly high resolution 1H, 13C NMR, DEPT, 2D 1H-1H and 1H-13C COSY NMR and HMBC analysis.