Reacción #42466

Ecuación de reacción

ethyl 4-butyl-8-iodo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylate

oxazole

n-butyllithium

→

title compound

Rendimiento 71.7%

Methyl 4-butyl-8-(1,3-oxazol-2-yl)-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylate

Rendimiento 71.7%

Disolventes

THF

ethyl acetate

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe mixture was warmed to 0° C. for 1 h
2. 2
   TemperaturaThe mixture was heated
3. 3
   Temperaturaat reflux for 3 h
4. 4
   Lavadowashed with water
5. 5
   SecadoThe organic solution was dried (sodium sulfate)
6. 6
   Concentraciónconcentrated under reduced pressure
7. 7
   OtroPurification by silica gel plug (1:1 acetate/hexanes)

Procedimiento

To a −70° C. solution of oxazole (227 mg) in tetrahydrofuran (10 mL) was added n-butyllithium (2.5 M in hexanes, 2 mL). After stirred at −70° C. for 30 min, zinc chloride (1 M in ethyl ether, 13 mL) was added. The mixture was warmed to 0° C. for 1 h. To this mixture was then added ethyl 4-butyl-8-iodo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylate (600 mg, 1.6 mmol) in THF (5 mL) followed by tetrakis triphenylphosphine palladium(0) (115 mg). The mixture was heated at reflux for 3 h, diluted with ethyl acetate (300 mL) and washed with water followed by brine. The organic solution was dried (sodium sulfate) and concentrated under reduced pressure. Purification by silica gel plug (1:1 acetate/hexanes) provided 363 mg of the title compound: 1H NMR (300 MHz, CDCl3) δ 7.96, 7.73, 7.40, 7.28, 4.44, 3.90, 3.43, 3.34, 1.61, 1.41, 0.98.

Fuente