Flosequinan

Flosequinan

Clinical data
ATC code	C01DB01 (WHO)
Identifiers
IUPAC name (RS)-7-fluoro-3-methanesulfinyl-1-methyl-1,4-dihydroquinolin-4-one
CAS Number	76568-02-0
PubChem CID	4474062
ChemSpider	3672315
UNII	6NB119DLU7
KEGG	D04195 Y
CompTox Dashboard (EPA)	DTXSID1048833
Chemical and physical data
Formula	C11H10FNO2S
Molar mass	239.267 g/mol g·mol−1
3D model (JSmol)	Interactive image
SMILES CN1C=C(C(=O)C2=C1C=C(C=C2)F)S(=O)C
InChI InChI=1S/C11H10FNO2S/c1-13-6-10(16(2)15)11(14)8-4-3-7(12)5-9(8)13/h3-6H,1-2H3 Key:UYGONJYYUKVHDD-UHFFFAOYSA-N
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Flosequinan is a quinolone vasodilator. It has direct relaxing effects on peripheral arteries and veins. It is administered orally in cases of congestive heart failure in patients who are not responsive to digitalis or ACE inhibitors. It was sold under the trade name Manoplax.

It was withdrawn from the US market in October 1993 due to an increased risk of hospitalization or death.

Synthesis

Both methods for forming the heterocyclic ring in quinolones involved cyclization into the carbocyclic ring. A closely related quinolone that displays cardiovascular rather than antibiotic activity is constructed by a condensation that closes the bond at the 2,3 position in the heterocyclic ring.

Flosequinan synthesis: U.S. patent 5,079,264 N.B.

The starting material (2) is obtained by reaction of the aminoacetophenone derivative (1) with ethyl formate. Heating the product in ethylene glycol methyl ether leads to an aldol-like cyclization and the formation of a quinolone ring. The product, flosequinan (3), displays vasodilator and cardiotonic activities.