Chlorotrifluoroethylene → 7-Fluoro-1,2,3,4-tetrahydronaphthalen-1-one

Temperature

90 °C

In a specially designed Kel-F reactor (cylindrical shape 1.25"od×3"h equipped with a screw cap and N2 inlet-outlet) was placed hydrogen fluoride-pyridine 6:4 solution (10 mL, prepared by diluting commercially available hydrogen fluoride-pyridine 7:3 solution with dry pyridine). 7-amino-tetralone (644 mg, 4.0 mmol), (Example 35, Step A) was added under N2 and the solution was cooled to 0°. Sodium nitrite (304 mg, 4.4 mol, 1.1 eq) was added in portions and the mixture was stirred for 30 minutes. The mixture was then heated at 90° C. for 1 hour with stirring. The reaction mixture was quenched with approx. 60 mL of ice/water and the solid that separated extracted with methylene chloride (3×30 mL). The combined extracts were washed with water and brine, dried over magnesium sulfate, filtered and evaporated to dryness under vacuum at room temperature. Purification by flash chromatography on silica, eluting with ethyl acetate/hexane (5:95), afforded pure 7-fluoro- 1-tetralone (367 mg, 2.2 mmol, 56%). 1H NMR (300MHz, CDCl3): 2.13 (m,2H), 2.65 (t,7Hz,2H), 2.94 (t,7Hz,2H), 7.1-7.3 (m,2H), 7.69 (dd;2,8Hz;1H). FAB-MS: calculated for C10H9FO 164; found 164 (M+,71%).

1. custom×3"h equipped with a screw
2. customcap
3. customN2 inlet-outlet) was placed
4. temperaturethe solution was cooled to 0°
5. stirringwith stirring
6. customThe reaction mixture was quenched with approx. 60 mL of ice/water
7. customthe solid that separated
8. extractionextracted with methylene chloride (3×30 mL)
9. washThe combined extracts were washed with water and brine
10. dry with materialdried over magnesium sulfate
11. filtrationfiltered
12. customevaporated to dryness under vacuum at room temperature
13. customPurification by flash chromatography on silica
14. washeluting with ethyl acetate/hexane (5:95)

ORD record

ord-9071a5beaa31462b953380a8193bd48b

Source dataset

uspto-grants-1994_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05310737