ChemSpider
IDs are definitely an important identifier to specify or name a chemical structure. Starting with the beta 4 version of the Chemical Identifier Resolver (CIR), ChemSpider IDs are now accepted both as input identifier as well as output representation. If it is used as input format, it has to be “classified” as ChemSpider ID (as we plan to enable the lookup of more database identifiers using the following format):
http://cactus.nci.nih.gov/chemical/structure/chemspider_id=1234567/smiles
The clue is, that for the conversion step “ChemSpider ID to structure” no local lookup in our databases is performed, but it is converted by connectiong to the ChemSpider’s InChI Resolver. If you want, you can combine this with other methods provided by CIR, for instance, the generation of all tautomers for a ChemSpider ID:
http://cactus.nci.nih.gov/chemical/structure/tautomers:chemspider_id=1234567/smiles http://cactus.nci.nih.gov/chemical/structure/tautomers:chemspider_id=1234567/image
Or you can “twirl” a ChemSpider ID:
http://cactus.nci.nih.gov/chemical/structure/chemspider_id=1234567/twirl
Of course, it also works in the other direction: the following example starts from an IUPAC name, which internally is converted into a chemical structure by OPSIN, and then is resolved into a ChemSpider ID (which again uses ChemSpider’s InChI Resolver):
http://cactus.nci.nih.gov/chemical/structure/(3β)-cholest-5-en-3-ol/chemspider_id
And some final example: resolve a set of Warfarin tautomers into ChemSpider IDs (unfortunately the ChemSpider InChI Resolver returns also deprecated ChemSpider records):
http://cactus.nci.nih.gov/chemical/structure/tautomers:warfarin/chemspider_id
You can do the same thing by starting from a ChemSpider ID, generate the tautomers and resolve them into a set of ChemSpider IDs again:
http://cactus.nci.nih.gov/chemical/structure/tautomers:chemspider_id=52602/chemspider_id
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