Fentanor

https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:8081
http://www.hmdb.ca/metabolites/HMDB0014830
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5775
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=46506535
https://www.chemspider.com/Chemical-Structure.5571.html
http://www.bindingdb.org/bind/chemsearch/marvin/MolStructure.jsp?monomerid=31046
https://mor.nlm.nih.gov/RxNav/search?searchBy=RXCUI&searchTerm=8153
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=8081
https://www.ebi.ac.uk/chembldb/index.php/compound/inspect/CHEMBL597
https://zinc.docking.org/substances/ZINC000000020251
http://bidd.nus.edu.sg/group/cjttd/ZFTTDDRUG.asp?ID=DAP000299
http://www.pharmgkb.org/drug/PA450926
http://www.guidetopharmacology.org/GRAC/LigandDisplayForward?ligandId=502
http://www.rxlist.com/cgi/generic3/phentol.htm
https://www.drugs.com/cons/phentolamine-injection.html
https://en.wikipedia.org/wiki/Phentolamine