Synthesis
Ethyl 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate (0.1 g, 0.32 mmol) was used as a raw material and dissolved in THF (5 ml). Concentrated HCl (45 μL, 0.7 mmol) was added to this solution. The reaction mixture was heated to reflux and the reaction was continued for 2 hours. The progress of the reaction was monitored by thin layer chromatography (TLC) and after confirming the completion of the reaction, the reaction mixture was cooled to room temperature. The precipitated solid was collected by filtration to afford the target product 7-chloro-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acid in a yield of 70 mg with 78% yield.
References
[1] Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 7, p. 2428 - 2433
[2] Journal of Medicinal Chemistry, 2002, vol. 45, # 25, p. 5564 - 5575
[3] Patent: WO2005/40164, 2005, A1. Location in patent: Page/Page column 10-12
