Oxygen atom in position 3 and nitrogen atom in position 5, or vice versa

Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings > not condensed with other rings > having two or three 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, e.g. ester or nitrile radicals, directly attached to ring carbon atoms > Oxygen and nitrogen or sulfur and nitrogen atoms > Oxygen atom in position 3 and nitrogen atom in position 5, or

Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings > not condensed with other rings > having two or three 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, e.g. ester or nitrile radicals, directly attached to ring carbon atoms > Oxygen and nitrogen or sulfur and nitrogen atoms > Oxygen atom in position 3 and nitrogen atom in position 5, or vice versa