(6R)-3-bromo-6-(hydroxymethyl)-5,6-dihydro-8H-[1,4]oxazino[2,3,4-ij]-1,5-naphthyridin-8-one

(6R)-6-(hydroxymethyl)-8-oxo-5,6-dihydro-8H-[1,4]oxazino[2,3,4-de]-1,5-naphthyridine-3-carbonitrile

[(6S)-3-bromo-8-oxo-5,6-dihydro-8H-[1,4]oxazino[2,3,4-ij]-1,5-naphthyridin-6-yl]methyl methanesulfonate

[(6S)-3-cyano-8-oxo-5,6-dihydro-8H-[1,4]oxazino[2,3,4-de]-1,5-naphthyridin-6-yl]methyl methanesulfonate

1,1-dimethylethyl (1-{[(6R)-3-bromo-8-oxo-5,6-dihydro-8H-[1,4]oxazino[2,3,4-de]-1,5-naphthyridin-6-yl]methyl}-4-piperidinyl)carbamate