Searching the Derwent Chemistry Resource Number Field

Searches the Derwent Chemistry Resource Number data field within a patent record.

Enter one or more numbers connected with the OR search operator. You can enter complete numbers or partial numbers using asterisk (*) wildcard. Do not, however, enter leading zeros in the stem or the suffix.


About Derwent Chemistry Resource Numbers

The Derwent Chemistry Resource Number is a unique registry identifier that indicates when two or more compounds are related to each other. They consist of a system of identifiers, the stem of which is the same for all related compounds, but with suffixes to indicate certain features such as stereochemistry, salts, isotopes, and physical forms.

The structure of the DCR Number is NNNNNNNN-NN-NN-NN, where:

  • "NNNNNNNN" is a 1 to 8-digit sequential number
  • "NN" is the first suffix for stereoisomers (number from 1-99)
  • "NN" is the second suffix for salts (number from 1-99)
  • "NN" is the third suffix to deal with other cases such as physical forms, isotopes, tautomers, etc., (number from 1-99)

Note the following:

The characters after the first hyphen (the first suffix) are for stereochemistry:


The default, used for compounds with no stereocentres or where the stereochemistry is not defined

For any compounds with stereocentres, the next available number is used (that is, 1 for the first stereoisomer encountered, 2 for the next one, 3 for the next one, up to 99).

The characters after the second hyphen (the second suffix) are for salts:


The default, used for the free acid or free base

The next available number is then used for the next salt encountered. The use is restricted to Group I and II or "simple" metal or amine salts of acids, simple (inorganic) salts of bases for example, halogens, etc. N.B. Inorganics and organo-metallic complexes will have unique identifiers as will most organic salts consisting of an organic acid and organic base.

The last characters (the third suffix) are for other cases where related compounds might be associated:

These include isotopes, tautomers, different physical forms, and other cases not covered above. This section will also be used if there is a need for a special version of a structure for a particular file or service. Sequential numbers will be assigned whenever different forms appear.


The default, used for parent compound


Search Examples
  • 208825-0-0-0
  • 95341*
  • 95341* OR 208825-0-0-0
  • 95341* OR 20882*
  • 208* OR 2088* OR 20882*


Did You Know ...

When the Derwent Chemistry Resource Number is searched from the Patent Data frame, the software searches the Derwent Innovations Index database; however, when searched from the Chemical Data frame, the software searches the Derwent Chemistry Resource database.