反応 #7846

反応方程式

2-[4-(bromomethyl)-3-methoxyphenyl]-1,3-benzoxazole

chlorotrimethylsilane

2-bromopyridine

1,2-dibromoethane

→

2-[3-methoxy-4-(pyridin-2-ylmethyl)phenyl]-1,3-benzoxazole

溶媒

THF

反応条件

後処理

1. 1
   温度The mixture was heated
2. 2
   温度at reflux for 1 h
3. 3
   ろ過The resultant organozinc reagent was filtered through a plug of Celite
4. 4
   その他transferred to a flask
5. 5
   その他The mixture was degassed with bubbling argon for 15 min
6. 6
   温度heated
7. 7
   温度at reflux for 12 h
8. 8
   workup.ADDITIONThe reaction was poured into H2O (40 mL)
9. 9
   抽出extracted with CH2Cl2 (2×30 mL)
10. 10
    乾燥The organic extracts were dried (MgSO4)
11. 11
    濃縮concentrated
12. 12
    その他to afford a colorless solid
13. 13
    その他Purification of the solid by flash chromatography on silica gel (EtOAc:hexanes 3:1)

実験手順

A solution of 2-[4-(bromomethyl)-3-methoxyphenyl]-1,3-benzoxazole (320 mg, 1.0 mmol) and THF (10 mL) was treated with Zn powder (activated by grinding with mortar and pestle), a drop of chlorotrimethylsilane, and a drop of 1,2-dibromoethane. The mixture was heated at reflux for 1 h. The resultant organozinc reagent was filtered through a plug of Celite, and transferred to a flask containing 2-bromopyridine (360 mg, 2.0 mmol) and Pd(Ph3P)4 (115 mg, 0.1 mmol). The mixture was degassed with bubbling argon for 15 min, and heated at reflux for 12 h. The reaction was poured into H2O (40 mL) and extracted with CH2Cl2 (2×30 mL). The organic extracts were dried (MgSO4) and concentrated to afford a colorless solid. Purification of the solid by flash chromatography on silica gel (EtOAc:hexanes 3:1) afforded the desired 2-[3-methoxy-4-(pyridin-2-ylmethyl)phenyl]-1,3-benzoxazole as a yellow solid: 1H NMR (CDCl3, 300 MHz) δ 8.55 (d, 1H), 7.76–7.82 (m, 3H), 7.56–7.62 (d, 2H), 7.32–7.36 (m, 3H), 7.11–7.16 (m, 2H), 4.23 (s, 2H), 3.95 (s, 3H). MS (ESI) 317 (M+H)+.

出典