Principal Directorate Patent Grant Automation
IPC M Project: M012
Directorate 2.7.1.5 - Classification
Subject: Heterocyclic Compounds (T049)
Proposal
Subclass: C07D
27 April 2007
This proposal is based on the final agreement of Trilateral Harmony project T049.
1. Proposal
D
Note (8) after C07D
N
<New note after C07D521/00>
Note: Group C07D521/00 is only to be used for the classification of heterocyclic
compounds of which the chemical structure is not specified, i.e. only in those rare cases
where the heterocyclic compounds cannot be classified properly in any of groups
C07D201/00 to C07D519/00.
2. Reasons
2.1. Deletion of Note (8)
Note (8) after C07D states that individual components of heterocyclic compounds may be
classified according to Note (6). However, we think that the practice of giving “additional
information” for individual components of heterocyclic compounds should be abandoned,
because it is creating confusion about which compounds are really meant by such an
additional classification notation (monocyclic -, or linked -, or condensed heterocyclic
compounds).
To illustrate the above statement, we can look at the example, covered by Note (6)(b) of
IPC8: pyridinyl-CH2-imidazolyl.
This compound should be classified in C07D401/06 (invention information) and according
to Note (8) it may also be classified as additional information in C07D213/58 and
C07D233/34.
We find these latter two classification symbols confusing and in a certain way misleading,
because no distinction can be made anymore between e.g. a pyridine compound,
classified in the additional information field, and a pyridine component of a compound
containing two or more linked hetero rings (a pyridine moiety and an imidazole moiety)
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classified in the same additional information field. Also the linking information between the
two moieties is completely lost.
For condensed ring systems having two or more relevant hetero rings covered by Note
(6)(c), the same accounts, for e.g. a pyridine ring condensed to a pyrrole ring should be
classified in C07D471/04. According to Note (8), additional classes C07D213/74 and
C07D207/34 should be added; no relation exists with the condensed character of the
compound in question.
2.2. New note under C07D521/00
We believe that the introduction of an explanatory Note before group 521/00 will prevent
the group from containing documents that could be classified elsewhere.
Anne Glanddier
Pierre Held
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