Reacción #7812

Ecuación de reacción

p-toluenesulfonic acid

3-hydroxy-4-methylbenzoic acid

SOCl2

2-aminophenol

triethylamine

→

5-(1,3-benzoxazol-2-yl)-2-methylphenol

Disolventes

toluene

EtOAc

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThis reaction was refluxed for 30 min
2. 2
   Otrothe excess SOCl2 removed in vacuo
3. 3
   workup.DISSOLUTIONThe oily acid chloride was dissolved in THF (15 mL)
4. 4
   Otrothe precipitate was removed by filtration
5. 5
   ConcentraciónThe filtrate was concentrated
6. 6
   Otrodried in vacuo
7. 7
   TemperaturaThe reaction was refluxed overnight
8. 8
   Temperaturacooled to rt
9. 9
   LavadoThe EtOAc solution was washed with H2O (3×5 mL)
10. 10
    Secadodried (MgSO4)
11. 11
    Filtraciónfiltered
12. 12
    Concentraciónconcentrated in vacuo
13. 13
    OtroThe residue was recrystallized in EtOAc

Procedimiento

To a 100 mL round-bottom flask with 3-hydroxy-4-methylbenzoic acid (2.5 g, 16.4 mmol) was added SOCl2 (15 mL) dropwise. This reaction was refluxed for 30 min, cooled to rt and the excess SOCl2 removed in vacuo. The oily acid chloride was dissolved in THF (15 mL) and the solution was added dropwise to a mixture of 2-aminophenol (1.8 g, 16.4 mmol), triethylamine (1.7 g, 16.4 mmol) in THF (30 mL) at 0° C. The reaction was then brought to rt for 0.5 h and the precipitate was removed by filtration. The filtrate was concentrated and dried in vacuo. To the dark brown solid residue was added toluene (20 mL) and p-toluenesulfonic acid (15.6 g, 82 mmol). The reaction was refluxed overnight, cooled to rt and dissolved in EtOAc (500 mL). The EtOAc solution was washed with H2O (3×5 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)+.

Fuente