Syntheses of flosequinan: a novel 4-quinolone shown to be useful in congestive heart failure
Abstract
Two synthetic routes to flosequinan 1 and flosequinoxan 2 are described in which either ring closure of the β-keto sulfoxides 12 or 13 with ortho esters or cyclisation of the anilinoacrylates 23, 28 or 29 are the key steps.