by oxygen atoms

Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings > with only hydrogen or carbon atoms directly attached to the ring nitrogen atom > having no double bonds between ring members or between ring members and non-ring members > with hydrocarbon or substituted hydrocarbon radicals directly attached to ring carbon atoms > with substituted hydrocarbon radicals attached to ring carbon atoms > with hydrocarbon radicals, substituted by singly bound oxygen or sulfur atoms > by oxygen atoms

Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings > with only hydrogen or carbon atoms directly attached to the ring nitrogen atom > having no double bonds between ring members or between ring members and non-ring members > with hydrocarbon or substituted hydrocarbon radicals directly attached to ring carbon atoms > with substituted hydrocarbon radicals attached to ring carbon atoms > with hydrocarbon radicals, substituted by singly bound oxygen or sulphur atoms > by oxygen atoms