Ethyl bromoacetate → [6-Methyl-5-(methyloxy)-2-oxo-1,3-benzoxazol-3(2H)-yl]acetic acid

To a solution of 6-methyl-5-(methyloxy)-1,3-benzoxazol-2(3H)-one (1.76 g, 9.8 mmol) in DMF (20 mL) was added NaH (470 mg, 11.8 mmol) in two portions. The reaction mixture was stirred for 30 minutes at room temperature, and ethyl bromoacetate (1.09 mL, 9.8 mmol) was added. The reaction mixture was stirred for 3 hour until all starting material was consumed, then poured into cold water (100 mL). The precipitate which formed was collected by filtration, washed with water, and dried in the air to afford a pale solid. This solid was dissolved in THF (20 mL) and NaOH (2.0 M, 4.9 mL) was added, and the reaction mixture was stirred at room temperature for 2 hours, poured into cold water (100 mL), and extracted with EtOAc (2×100 mL). The aqueous layer was acidified with HCl (6 N) to pH˜1, extracted with EtOAc (3×100 mL). The organic extracts were combined, washed with brine, and dried (Na2SO4). The solvent was removed via rotovap to give the title compound (2.16 g, 93%) as a pale solid. MS (ES) m/e 238 [M+H]+.

1. stirringThe reaction mixture was stirred for 3 hour until all starting material
2. customwas consumed
3. additionpoured into cold water (100 mL)
4. customThe precipitate which formed
5. filtrationwas collected by filtration
6. washwashed with water
7. customdried in the air
8. customto afford a pale solid
9. stirringthe reaction mixture was stirred at room temperature for 2 hours
10. extractionextracted with EtOAc (2×100 mL)
11. extractionextracted with EtOAc (3×100 mL)
12. washwashed with brine
13. dry with materialdried (Na2SO4)
14. customThe solvent was removed via rotovap

ORD record

ord-f0d65bb7a21c487589892b7ff985d175

Source dataset

uspto-grants-2008_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07432258B2