Formatting of input data for UniChem queries.

Below are some simple tips for reviewing your query strings for the correct formatting.

  1. src_compound_id
  2. src_id
  3. InChIs and InChIKeys
  4. Web interface Queries


src_compound_ids are treated in a case sensitive manner. For example, querying with 'chembl123' instead of 'CHEMBL123' will return nothing, as the lower-case form is currently not a valid ChEMBL id.

This distinction is made in UniChem to account for the possibility that a source may change the case in an src_compound_id from one release to another: UniChem must distinguish between these to indicate the current and obsolete versions to the user.


src_ids are integers.

InChIs and InChIKeys

Standard InChIs in UniChem are calculated with version 1 of the IUPAC International Chemical Identifier (InChI) generation software. Full detailed information of the format of valid Standard InChIs and InChIKeys using this software may be found here . Below are some simple first pass checks you can do before consulting the more detailed documentation cited in the above link.

Standard InChIs

Standard InChIs in UniChem should always begin with ...


Thus, for example, the following...


... is a valid Standard InChi in UniChem.

Standard InChIKeys

Standard InChIKeys should always follow the following 27-character format...


... where X is any uppercase letter, and the two hyphens separate three blocks of 14, 10 and 1 uppercase letters respectively.
'SA' in positions 9 and 10 of the second block signifies that this is a key for a Standard ('S') Inchi, generated using version 1 ('A') of the InChI software.

Thus, for example, the following...


... is a valid Standard InChiKey in UniChem.

Web Interface Queries

Enter plain text only into the query field. New-lines and/or white space may be used to separate entries. Remove all other non-printing special characters.
Note that querying with src_compound_ids requires additional information:
1. The src_id for the source of the src_compound_id's.
2. An indication of whether query src_compound_ids with 'obsolete' assignments should be included in the query (go here for a more detailed explanation of this option). It is recommended that normally users will probably NOT wish to have this option ticked.
Note, also, that for large queries the output may difficult to interpret, and slow to load in your browser. For larger queries, therefore, users are strongly advised to use the web services instead.

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