5- Oxo-2,3-dihydro-5H-pyrido

Oxo-2,3-dihydro-5H-pyrido[l,2,3-de][l,4]benzoxazine-3-carbalde-hydes were reacted with tert-bu tyl piperidin-4-ylcarbamate, then the reaction mixture was treated with sodium triacetoxyborohydride to give 3-[4-(ferf-butoxycarbonylamino)piperidin-l-yl)methyl derivatives (08WOP2008/120003). 8-Fluoro-3-oxo-2,3,6,7-tetrahydro-5H-pyrido [l,2,3-cfe][l,4]benzoxazin-7-carbaldehyde was similarly reacted with cyclic amines, then with (polystyrylmethyl)trimethylammonium cya-noborohydride in acidified MeOH (08WOP2008/116815). 

---