4,8-Ethenopyrrolo[3',4':3,4]cyclobut[1,2-f]isoindole-1,3,5,7(2H,6H)-tetrone, 2,6-bis[(acetyloxy)methyl]-3a,3b,4,4a,7a,8,8a,8b-octahydro- 4,8-Ethenopyrrolo[3',4':3,4]cyclobut[1,2-f]isoindole-1,3,5,7(2H,6H)-tetrone,2,6-bis[(acetyloxy)methyl]-3a,3b,4,4a,7a,8,8a,8b-octahydro- NSC363226