Phosphorus oxychloride → 2-Chloro-8-fluoroquinoline

Temperature

125 °C

8-Fluoroquinolin-2(1H)-one (26.0 g, 159 mmol) was slurried with phosphoryl trichloride (163 ml, 1.73 mol, 11 eq) and heated to 125° C. for 2 h. The reaction was cooled to rt and poured onto 1.2 L of ice water with vigorous stirring. When the mixture had cooled to rt, the orange solid was filtered and washed with water and dried under vacuum overnight to afford 27 g of crude material. The crude material was recrystallized from hexanes by dissolving in ˜700 mL of hexanes at reflux and decanting away from residual tar. The hexane solution was cooled to 0° C. and the precipitate 2-chloro-8-fluoroquinoline was filtered. The mother liquor was concentrated in vacuo and recrystallized from hexanes to obtain a second crop of 2-chloro-8-fluoroquinoline (21.3 g, 74% total yield).

1. temperatureThe reaction was cooled to rt
2. temperatureWhen the mixture had cooled to rt
3. filtrationthe orange solid was filtered
4. washwashed with water
5. customdried under vacuum overnight
6. customto afford 27 g of crude material
7. customThe crude material was recrystallized from hexanes
8. dissolutionby dissolving in ˜700 mL of hexanes
9. temperatureat reflux
10. customdecanting away from residual tar
11. temperatureThe hexane solution was cooled to 0° C.
12. filtrationthe precipitate 2-chloro-8-fluoroquinoline was filtered
13. concentrationThe mother liquor was concentrated in vacuo
14. customrecrystallized from hexanes

ORD record

ord-148ddc36d111460cbf6be90ae258e657

Source dataset

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08835432B2