Showing structure for 9a-{3,4a,5-trimethyl-2-oxo-4h,5h,6h,7h,8h-naphtho[2,3-b]furan-9a-yl}-3,4a,5-trimethyl-4h,5h,6h,7h,8h-naphtho[2,3-b]furan-2-one