62288-03-3 Dehydrocyclobutatusin NSC270914 PHOTOBARBATUSIN I Spiro(cyclobuta[def]phenanthrene-2(1H),1'-cyclopropane)-1,5(4H)-dione, 3,7-bis(acetyloxy)-3,3a,3b,6,6a,7,8,8c-octahydro-3a,8-dihydroxy-2',6,6,8c-tetramethyl-