反应详情

4-Dimethylaminopyridine (cat. amount) was added to the mixture of acetic anhydride (0.162 mL), diisopropylethylamine (0.697 mL) and the product from step (ii) (760 mg) in THF (10 mL). After the mixture was stirred at RT for 3.5 h, the reaction mixture was diluted with water and sat. sodium hydrogen dicarbonate and extracted with EtOAc. The combined organic layer was washed with water and brine, dried and concentrated under reduced pressure to afford the crude product as pale yellow oil, which was used for next reaction without further purification; 1H NMR (CDCl3); 6.81 (1H, d), 6.44 (1H, d), 6.38 (1H, dd), 4.79 (2H, br s), 4.25-4.15 (1H, m), 3.99 (2H, t), 3.96-3.88 (2H, m), 3.85 (3H, s), 3.76 (2H, t), 3.58 (2H, s), 2.33 (3H, s), 1.97 (3H, s), 2.00-1.88 (2H, m), 1.86-1.71 (1H, m), 1.64-1.50 (1H, m), 1.48-1.32 (1H, m), 1.30-0.95 (3H, m), 0.86 (9H, s), 0.76 (3H, t), 0.02 (6H, s); LC-MS: m/z 576.

1. extractionextracted with EtOAc
2. washThe combined organic layer was washed with water and brine
3. customdried
4. concentrationconcentrated under reduced pressure