反应详情

KOH (0.65 g, 11.5 mmol) in water (3.0 mL) was added to 19b (1.20 g, 3.8 mmol) in methanol (15 mL) and stirred at rt overnight. The reaction was neutralized with conc. HCl (1 mL) and then concentrated. The crude reaction mixture was evaporated from toluene to remove water. The crude amine was taken up in dichloromethane (30 mL) and triethylamine (2.5 mL, 19.2 mmol) and pivaloyl chloride (0.9 mL, 7.7 mmol) were added. This was stirred at rt for 4 h and then water was added to quench the reaction. The aqueous layer was extracted with dichloromethane (3×) and the combined organics were dried (MgSO4), filtered and evaporated to give the crude product. The crude product was purified by flash chromatography on Biotage using EtOAc/Hexanes (50-100%) to give 19c as a white solid (0.91 g, 79%). (M+H)+=301. 1H NMR (400 MHz, CDCl3) δ ppm 7.90 (s, 1H); 7.30 (d, J=7.3 Hz, 1H); 7.22 (t, J=7.7 Hz, 1H); 7.08 (t, J=7.6 Hz, 1H); 6.78 (d, J=7.8 Hz, 1H); 4.30 (m, 2H); 3.18 (m, 2H); 2.75 (s, 2H); 1.91 (m, 2H); 1.71 (m, 2H); 1.28 (s, 9H).

1. concentrationconcentrated
2. customThe crude reaction mixture
3. customwas evaporated from toluene
4. customto remove water
5. stirringThis was stirred at rt for 4 h
6. customto quench
7. customthe reaction
8. extractionThe aqueous layer was extracted with dichloromethane (3×)
9. dry with materialthe combined organics were dried (MgSO4)
10. filtrationfiltered
11. customevaporated
12. customto give the crude product
13. customThe crude product was purified by flash chromatography on Biotage