The ring being spiro-condensed with carbocyclic or heterocyclic ring systems

Full Title

Medicinal preparations containing organic active ingredients > Heterocyclic compounds > having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins > having six-membered rings with one nitrogen as the only ring hetero atom > The ring being spiro-condensed with carbocyclic or heterocyclic ring systems