반응 #7846

반응 방정식

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

용매

THF

반응 조건

후처리

1. 1
   온도The mixture was heated
2. 2
   온도at reflux for 1 h
3. 3
   여과The resultant organozinc reagent was filtered through a plug of Celite
4. 4
   기타transferred to a flask
5. 5
   기타The mixture was degassed with bubbling argon for 15 min
6. 6
   온도heated
7. 7
   온도at reflux for 12 h
8. 8
   workup.ADDITIONThe reaction was poured into H2O (40 mL)
9. 9
   추출extracted with CH2Cl2 (2×30 mL)
10. 10
    건조The organic extracts were dried (MgSO4)
11. 11
    농축concentrated
12. 12
    기타to afford a colorless solid
13. 13
    기타Purification of the solid by flash chromatography on silica gel (EtOAc:hexanes 3:1)

실험 절차

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)+.

출처