Zopyrin

https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:9334
http://www.hmdb.ca/metabolites/HMDB0014933
http://www.genome.jp/dbget-bin/www_bget?drug:D00448
http://www.genome.jp/dbget-bin/www_bget?cpd:C07316
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5359476
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=46505451
https://www.chemspider.com/Chemical-Structure.10605946.html
http://www.bindingdb.org/bind/chemsearch/marvin/MolStructure.jsp?monomerid=50103596
https://mor.nlm.nih.gov/RxNav/search?searchBy=RXCUI&searchTerm=9524
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=9334
https://www.ebi.ac.uk/chembldb/index.php/compound/inspect/CHEMBL421
https://zinc.docking.org/substances/ZINC000003831490
http://bidd.nus.edu.sg/group/cjttd/ZFTTDDRUG.asp?ID=DAP000153
http://www.pharmgkb.org/drug/PA451547
https://www.ebi.ac.uk/pdbe-srv/pdbechem/chemicalCompound/show/SAS
http://www.rxlist.com/cgi/generic/sulfasal.htm
https://www.drugs.com/cdi/sulfasalazine.html
https://en.wikipedia.org/wiki/Sulfasalazine