A61K31/395
having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
A61K31/395
having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
A61K31/495
having six-membered rings with two; or more; nitrogen atoms as the only ring heteroatoms, e.g. piperazine; or tetrazines
A61K31/495
having six-membered rings with two; or more; nitrogen atoms as the only ring heteroatoms, e.g. piperazine; or tetrazines
A61K31/505
Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim
A61K31/505
Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim
A61K31/506
not condensed and containing further heterocyclic rings
A61K31/506
not condensed and containing further heterocyclic rings