Hydroxylamine HCl → 6-Fluoro-3-methyl-1,2-benzoxazole

Temperature

60 °C

A mixture of 1-(4-fluoro-2-hydroxyphenyl)ethanone (20 g), hydroxyammonium chloride (18.1 g), sodium acetate (16 g) and methanol (500 mL) was stirred at 60° C. for 1 hr. The reaction mixture was added to ice water, and the obtained crystallized product was collected by filtration and dissolved in tetrahydrofuran (400 mL). N,N′-carbonyldiimidazole (22.5 g) and then a solution of triethylamine (22.3 mL) in tetrahydrofuran (100 mL) were added, and the mixture was stirred at 70° C. for 1 hr. The reaction mixture was diluted with diethyl ether, washed with water and then with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure to give the title compound as colorless crystals (13.7 g, 70%).

1. customthe obtained crystallized product
2. filtrationwas collected by filtration
3. dissolutiondissolved in tetrahydrofuran (400 mL)
4. additionN,N′-carbonyldiimidazole (22.5 g) and then a solution of triethylamine (22.3 mL) in tetrahydrofuran (100 mL) were added
5. stirringthe mixture was stirred at 70° C. for 1 hr
6. additionThe reaction mixture was diluted with diethyl ether
7. washwashed with water
8. dry with materialwith saturated brine, and dried over anhydrous magnesium sulfate
9. customThe solvent was evaporated under reduced pressure

ORD record

ord-5672f980367949bb8da4ec13cf009e58

Source dataset

uspto-grants-2010_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07803940B2