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C07D311/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings
C07D311/02—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings ortho- or peri-condensed with carbocyclic rings or ring systems
C07D311/78—Ring systems having three or more relevant rings
C07D311/84—Xanthenes with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 9
C07D311/86—Oxygen atoms, e.g. xanthones
C—CHEMISTRY; METALLURGY
C07—ORGANIC CHEMISTRY
C07D—HETEROCYCLIC COMPOUNDS
C07D311/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings
C07D311/02—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings ortho- or peri-condensed with carbocyclic rings or ring systems
C07D311/78—Ring systems having three or more relevant rings