2-Aminophenol → 5-(1,3-Benzoxazol-2-yl)-2-methylphenol

To a 100 mL round-bottom flask with 3-hydroxy-4-methylbenzoic acid (2.5 g, 16.4 mmol), was added dropwise SOCl2 (15 mL). The reaction was refluxed for 30 min and cooled to rt. The excess of SOCl2 was removed in vacuo and the oily acid chloride was dissolved in THF (15 mL). This resulting solution was added dropwise to a mixture of 2-aminophenol (1.8 g, 16.4 mmol), triethylamine (1.7 g, 16.4 mmol) and THF (30 mL) at 0° C. The resulting reaction mixture was then brought to rt for 30 min and the resulting precipitate was removed by filtration. The filtrate was concentrated and dried under vacuum. The resulting dark brown solid residue was dissolved in toluene (20 mL) and p-toluenesulfonic acid (15.6 g, 82 mmol) was added. The reaction was refluxed overnight, cooled at rt and EtOAc (500 mL) was added. The EtOAc solution was washed with brine (3×50 mL), dried (MgSO4), filtered and concentrated in vacuo. The residue was recrystallized in EtOAc to afford 5-(1,3-benzoxazol-2-yl)-2-methylphenol as a light yellow solid. MS (ESI) 226 (M+H)+.

1. temperatureThe reaction was refluxed for 30 min
2. customThe excess of SOCl2 was removed in vacuo
3. dissolutionthe oily acid chloride was dissolved in THF (15 mL)
4. customThe resulting reaction mixture
5. customthe resulting precipitate was removed by filtration
6. concentrationThe filtrate was concentrated
7. customdried under vacuum
8. dissolutionThe resulting dark brown solid residue was dissolved in toluene (20 mL)
9. temperatureThe reaction was refluxed overnight
10. temperaturecooled at rt
11. washThe EtOAc solution was washed with brine (3×50 mL)
12. dry with materialdried (MgSO4)
13. filtrationfiltered
14. concentrationconcentrated in vacuo
15. customThe residue was recrystallized in EtOAc

ORD record

ord-bde3b58972f64cb4a1179033e865bdef

Source dataset

uspto-grants-2006_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07087601B2