反応 #42466

反応方程式

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

oxazole

n-butyllithium

→

title compound

収率 71.7%

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

収率 71.7%

溶媒

THF

ethyl acetate

tetrahydrofuran

反応条件

後処理

1. 1
   温度The mixture was warmed to 0° C. for 1 h
2. 2
   温度The mixture was heated
3. 3
   温度at reflux for 3 h
4. 4
   洗浄washed with water
5. 5
   乾燥The organic solution was dried (sodium sulfate)
6. 6
   濃縮concentrated under reduced pressure
7. 7
   その他Purification by silica gel plug (1:1 acetate/hexanes)

実験手順

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.

出典