(6S)-6-[(4-Amino-1-piperidinyl)methyl]-3-fluoro-5,6-dihydro-8H-[1,4]oxazino[2,3,4-de]-1,5-naphthyridin-8-one dihydrochloride 、
[1,3]Oxa硫醇o[5,4-c]吡啶-6-甲醛 以to afford the free base of the title compound as a white solid (0.090 g, 38%)的产率得到(6S)-3-fluoro-6-({4-[([1,3]oxathiolo[5,4-c]pyridin-6-ylmethyl)amino]-1-piperidinyl}methyl)-5,6-dihydro-8H-[1,4]oxazino[2,3,4-de]-1,5-naphthyridin-8-one