Hydrochloric Acid → 6-fluoro-7-hydroxy-3,4-dihydro-2H-1-benzopyran-4-one

Temperature

80 °C

In a 15 mL vial was added 4-fluorobenzene-1,3-diol (500 mg, 3.9 mmol) and 3-chloropropanoic acid (424 mg, 3.9 mmol) and trifluoromethanesulfonic acid (2 mL). The mixture was heated to 80° C. and stirred at that temperature for 4 hour. The reaction was cooled and poured into water (10 mL). The product was extracted with ethyl acetate, dried over anhydrous Na2SO4, filtered, concentrated. To the dark red solid obtained was added sodium hydroxide (2 N, 5 mL) and the solution was let stirred at RT for 18 hours. The mixture was neutralized with 2 N HCl, extracted with EtOAc. The organic phase was dried over anhydrous Na2SO4, filtered, concentrated. The crude was used to next step without purification. 1H NMR (500 MHz, CDCl3, δ in ppm): 7.61 (1H, d, J=10.3 Hz), 6.56 (1H, d, J=3.1 Hz), 4.48 (2H, t), 2.78 (2H, t).

1. temperatureThe reaction was cooled
2. extractionThe product was extracted with ethyl acetate
3. dry with materialdried over anhydrous Na2SO4
4. filtrationfiltered
5. concentrationconcentrated
6. customTo the dark red solid obtained
7. stirringthe solution was let stirred at RT for 18 hours
8. extractionextracted with EtOAc
9. dry with materialThe organic phase was dried over anhydrous Na2SO4
10. filtrationfiltered
11. concentrationconcentrated
12. customThe crude was used to next step without purification

ORD record

ord-8502a16d50774db59aab56198edd6f50

Source dataset

uspto-grants-2015_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09073882B2