Trimethyl orthoacetate → 1,3-Benzoxazol-4-ol

A mixture of 2-amino-benzene-1,3-diol hydrochloride (2.00 g, 12.4 mmol) and trimethyl orthoacetate (15 mL) was treated with concentrated sulfuric acid (5 drops) and the resulting mixture heated at reflux for 3 h, cooled and allowed to stand at room temperature overnight. The resulting mixture was concentrated in vacuo and the residue treated with ethyl acetate (200 mL), washed with water (200 mL) and brine (100 mL). The combined aqueous phases were extracted with ethyl acetate (200 mL) and the combined organic phases washed with brine and dried over sodium sulfate. The mixture was filtered and concentrated in vacuo which afforded benzooxazol-4-ol (0.94 g, 51%) as a yellow solid.

1. temperaturethe resulting mixture heated
2. temperatureat reflux for 3 h
3. temperaturecooled
4. concentrationThe resulting mixture was concentrated in vacuo
5. additionthe residue treated with ethyl acetate (200 mL)
6. washwashed with water (200 mL) and brine (100 mL)
7. extractionThe combined aqueous phases were extracted with ethyl acetate (200 mL)
8. washthe combined organic phases washed with brine
9. dry with materialdried over sodium sulfate
10. filtrationThe mixture was filtered
11. concentrationconcentrated in vacuo which

ORD record

ord-e80020f93f3445a18bd2b839f88c261b

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07741327B2