Opus

https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:6402
http://www.hmdb.ca/metabolites/HMDB0015229
http://www.genome.jp/dbget-bin/www_bget?drug:D00749
http://www.genome.jp/dbget-bin/www_bget?cpd:C07905
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=3899
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=46506013
https://www.chemspider.com/Chemical-Structure.3762.html
http://www.bindingdb.org/bind/chemsearch/marvin/MolStructure.jsp?monomerid=50054601
https://mor.nlm.nih.gov/RxNav/search?searchBy=RXCUI&searchTerm=27169
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=6402
https://www.ebi.ac.uk/chembldb/index.php/compound/inspect/CHEMBL960
https://zinc.docking.org/substances/ZINC000000004840
http://bidd.nus.edu.sg/group/cjttd/ZFTTDDRUG.asp?ID=DAP000636
http://www.pharmgkb.org/drug/PA450192
http://www.rxlist.com/cgi/generic3/leflunomide.htm
https://www.drugs.com/cdi/leflunomide.html
https://en.wikipedia.org/wiki/Leflunomide