Descriptions for A01N43/00 and notes/indexes are displayed on this screen.


Note(s)
    In this group,—the following terms or expressions are used with the meanings indicated:[3]
      "hetero ring" is a ring having at least one halogen, nitrogen, oxygen or sulfur atom as a ring member;"bridged" means the presence of at least one fusion other than ortho, peri and spiro;two rings are "condensed" if they share at least one ring member, i.e. "spiro" and "bridged" are considered as condensed;"condensed ring system" is a ring system in which all rings are condensed among themselves.
    In this group, the number of rings in a condensed ring system equals the number of scissions necessary to convert the ring system into one acyclic chain. The relevant rings in a condensed system are chosen according to the following criteria consecutively:
      lowest number of ring members,highest number of hetero atoms as ring members.
    Ring members shared by two or more rings are regarded as being a member of each of these rings.