Previously disclosed dihydropyrazolopyrimidines are potent and selective blockers of IKur current. A potential liability with this chemotype is the formation of a reactive metabolite which demonstrated covalent binding to protein in vitro. When substituted at the 2 or 3 position, this template yielded potent IKur inhibitors, with selectivity over h ERG which did not form reactive metabolites. Subsequent optimization for potency and PK properties lead ...
