6-({[(3R,6S)-6-[(1S,2R)-2-(3-fluoro-6-methoxy-1,5-naphthyridin-4-yl)-1,2-dihydroxyethyl]oxan-3-yl]amino}methyl)-2H,3H,4H-pyrido[3,2-b][1,4]thiazin-3-one