Hydrochloric Acid → 5-amino-7-fluoroquinolin-2(1H)-one

To a solution of 2-bromo-3-fluoroaniline (6.5 g, 34.17 mmol) and pyridine (2.7 g, 34.17 mmol) in 20 ml of CH2Cl2, cinnamoyl chloride (5.95 g, 35.88 mol) in 10 ml CH2Cl2 are added dropwise and mixture was refluxed for 30 min. The reaction mixture is diluted with CH2Cl2, the organic layer washed with diluted HCl, saturated Na2CO3 solution, water, and dried (Na2SO4). The solvent is removed in vacuo to give 10.5 g of N-(2-bromo-3-fluorophenyl)-3-phenylacrylamide. To a solution of N-(2-bromo-3-fluorophenyl)-3-phenylacrylamide (10.5 g, 32.8 mmol) in 70 ml of chlor-benzene at 130° C. AlCl3 (21.9 g, 0.164 mol) is added portionwise, the mixture is stirred at this temperature 2 h and poured in ice-water. The precipitate is filtered off and dried. Yield 6.05 g (76%). 6 g (24.8 mmol) of 8-bromo-7-fluoro-1H-quinolin-2-one are refluxed in 30 mL of POCl3 during 2 h, then poured on ice, extracted with benzene. the benzene extract dried (Na2SO4) to yield 6.1 g 8-bromo-2-chloro-7-fluoroquinoline after solvent removal. To a mixture of 10 ml 10%-oleum and 1.4 g (22.2 mmol) of fuming HNO3 8-bromo-2-chloro-7-fluoroquinoline (4.8 g 18.5 mmol) is added portionwise. The mixture is heated at 100° C. for 2 h. Additional HNO3 (0.17 g) is added and stirred for additional 1 h. The reaction mixture is poured in ice-water, extracted with EtOAc, filtered through silica gel, and crystallized from heptane-toluene to yield 2.3 g (50%) 8-bromo-2-chloro-7-fluoro-5-nitroquinoline. 2.3 g (7.54 mmol) of 8-bromo-2-chloro-7-fluoro-5-nitroquinoline are heated at 100° C. for 5 h in a solution containing 16 ml of CH3COOH, 3.2 ml of H2O and 5 ml of conc. HCl. The mixture is poured in water, the formed precipitate is filtered off, stirred in EtOAc and filtered to yield 1.71 g. 8-bromo-7-fluoro-5-nitro-1H-quinolin-2-one. To a suspension 1.7 g (5.92 mmol) of 8-bromo-7-fluoro-5-nitro-1H-quinolin-2-one and 2.3 g (35.5 mmol) of HCOONH4 in 10 ml of ethanol 0.1 g 10% Pd—C are added, and stirred for 2 h at 60° C. A solid disappeared and then formed again. The precipitate is filtered off, dissolved in 3 ml of DMSO and filtered through silica gel. 15 ml of water are added to the eluate, the precipitate is filtered off and dried to yield 0.5 g (47%) 5-Amino-7-fluoro-1H-quinolin-2-one. 1H-NMR (DMSO-d6); δ=6.14 (dd, 1H), 6.20 (dd, 1H), 6.23 (d, 1H), 6.27 (br, 2H), 8.06 (d, 1H), 11.50 (br., 1H).

1. filtrationthe formed precipitate is filtered off
2. filtrationfiltered
3. customto yield 1.71 g
4. stirringstirred for 2 h at 60° C
5. customformed again
6. filtrationThe precipitate is filtered off
7. dissolutiondissolved in 3 ml of DMSO
8. filtrationfiltered through silica gel
9. addition15 ml of water are added to the eluate
10. filtrationthe precipitate is filtered off
11. customdried

ORD record

ord-a01e0a8520234e1a92923338833f329e

Source dataset

uspto-grants-2014_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08680117B2