6H-6,10-Etheno-3,5a-methano-9H-cyclobuta[4a,5]naphtho[2,3-c]furan-1,2,4,5-tetracarboxylic acid, 2a,3,6a,7,9a,10-hexahydro-7,9-dioxo-, tetramethyl ester AIDS-135880 AIDS135880 NSC636514