14-Oxabicyclo[11.3.1]heptadeca-4,8-dien-15-one, 2-(acetyloxy)-12-hydroxy-4,8,12-trimethyl-16- methylene-, [1S-(1R*,2R*,4Z,8Z,12S*,13R*)]- 28028-68-4 Crassin acetate NSC46728