(3S)-10-Fluoro-2,3-dihydro-3-Methyl-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic Acid

(3S)-10-Fluoro-2,3-dihydro-3-methyl-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic Acid is an intermediate in the synthesis of Levofloxacin, an antibiotic used against gram-negative organisms.

(3S)-10-Fluoro-2,3-dihydro-3-Methyl-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic Acid is synthesized by reacting ethyl (S)-10-fluoro-3-methyl-7-oxo- 2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylate with Potassium hydroxide in Tetrahydrofuran by reflux.¹

[1] JEFFREY L. GRAY. Synthesis and Biological Testing of Non-Fluorinated Analogues of Levofloxacin.[J]. ChemInform, 2003, 34 42. DOI:10.1002/chin.200342162.