Hydrochloric Acid → 5-Nitro-2,3-dihydro-1,3-benzoxazol-2-one

2-Amino-4-nitrophenol (30.0 g) and 1,1′-carbonyldiimidazole (47.34 g) were dissolved in THF (300 mL). The mixture was refluxed over night. The reaction mixture was cooled, poured into ice/water and acidified with 1M aqueous HCl to pH 2. The aqueous layer was extracted two times with ethyl acetate. The combined organic layers were washed with brine, dried over Na2SO4, filtered and the solvent was evaporated. Methanol (150 mL) was added to the resulting precipitate and the mixture was stirred for 30 minutes at r.t. The resulting solid was filtered off and dried in vacuo. The title compound was obtained as a yellow solid (32.32 g, 88%). MS (neg. ion, m/e)=179.0 [(M−H)−].

1. temperatureThe mixture was refluxed over night
2. temperatureThe reaction mixture was cooled
3. extractionThe aqueous layer was extracted two times with ethyl acetate
4. washThe combined organic layers were washed with brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. customthe solvent was evaporated
8. additionMethanol (150 mL) was added to the resulting precipitate
9. filtrationThe resulting solid was filtered off
10. customdried in vacuo

ORD record

ord-aeb481e1e72f4bdfa82cbdc62760dcc8

Source dataset

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08450313B2