Hydrochloric Acid → 5-(2-Fluoropropan-2-yl)isoxazol-3-amine

온도

0 °C

To dry methanol (10 mL) at room temperature, was added portionwise sodium metal (145 mg, 6.30 mmol). After all metal had dissolved, the reaction mixture was cooled to 0° C. and hydroxylamine hydrochloride (438 mg, 6.30 mmol) was added in one portion. The reaction mixture was stirred for 15 mins before adding a solution of 4-fluoro-3-methoxy-4-methylpent-2-enenitrile (500 mg, 3.50 mmol) in dry methanol (3 mL). The mixture was heated at 70° C. for 16 h. Concentrated hydrochloric acid (0.8 mL, 9.6 mmol) was added and the reaction mixture stirred at 80° C. for 30 mins. After cooling to room temperature, the reaction was concentrated under reduced pressure to give an orange foam which was dissolved in water (50 mL) and adjusted to pH 10 using aq 1M NaOH solution. The aqueous layer was then extracted with dichloromethane (3×50 mL) and the combined organic layers were washed with brine (50 mL), dried over MgSO4 and concentrated under reduced pressure to give a yellow oil. The crude product was purified by silica gel chromatography eluting with 12% ethyl acetate in hexanes to 100% ethyl acetate to afford 5-(2-fluoropropan-2-yl)isoxazol-3-amine as a cream solid (64 mg, 13%). 1H NMR (300 MHz, CDCl3) δ 5.82 (s, 1H), 4.08 (brs, 2H), 1.71 (d, J=21 Hz, 6H); LC-MS (ESI) m/z 145 (M+H)+.

1. dissolutionAfter all metal had dissolved
2. temperatureThe mixture was heated at 70° C. for 16 h
3. stirringthe reaction mixture stirred at 80° C. for 30 mins
4. temperatureAfter cooling to room temperature
5. concentrationthe reaction was concentrated under reduced pressure
6. customto give an orange foam which
7. extractionThe aqueous layer was then extracted with dichloromethane (3×50 mL)
8. washthe combined organic layers were washed with brine (50 mL)
9. dry with materialdried over MgSO4
10. concentrationconcentrated under reduced pressure
11. customto give a yellow oil
12. customThe crude product was purified by silica gel chromatography
13. washeluting with 12% ethyl acetate in hexanes to 100% ethyl acetate

ORD 기록

ord-63e4dff17e40461aac3b23be6386e519

출처 데이터셋

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US09320739B2