A synthetic dihydroxyflavone that is 5,7-dihydroxyflavone which is substituted by a 3-hydroxy-1-methylpiperidin-4-yl group at position 8 and by a chlorine at the 2' position (the (-)-3S,4R stereoisomer). A cyclin-dependent kinase 9 (CDK9) inhibitor, it has been studied for the treatment of acute myeloid leukaemia, arthritis and atherosclerotic plaque formation.