with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms, e.g. orotic acid

Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings > not condensed with other rings > having three or more double bonds between ring members or between ring members and non-ring members > with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms > Two or more oxygen, sulfur or nitrogen atoms > Two oxygen atoms > as doubly bound oxygen atoms or as unsubstituted hydroxy radicals > with other hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms > with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms, e.g. orotic acid

Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings > not condensed with other rings > having three or more double bonds between ring members or between ring members and non-ring members > with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms > Two or more oxygen, sulphur or nitrogen atoms > Two oxygen atoms > as doubly bound oxygen atoms or as unsubstituted hydroxy radicals > with other hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms > with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms, e.g. orotic acid