Oxygen atoms

Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom > not condensed with other rings > 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 to ring carbon atoms > Oxygen atoms

Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom > not condensed with other rings > 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 to ring carbon atoms (halogen atoms C07D223/04) > Oxygen atoms