methyl 4,7,9,10'-tetramethoxy-5,8,9'-trioxo-4',5,8,9'-tetrahydro-3H,3'H-spiro[naphtho[2,3-b]furan-2,2'-pyrano[4,3-g]chromene]-7'-carboxylate

methyl 5,7,8,10'-tetramethoxy-4,9,9'-trioxo-4,4',9,9'-tetrahydro-3H,3'H-spiro[naphtho[2,3-b]furan-2,2'-pyrano[4,3-g]chromene]-7'-carboxylate

methyl 6,7,9,10'-tetramethoxy-4,5,9'-trioxo-4,4',5,9'-tetrahydro-3H,3'H-spiro[naphtho[1,2-b]furan-2,2'-pyrano[4,3-g]chromene]-7'-carboxylate

4-Chloro-purpuromycin

绛红霉素