反应详情

To a solution of Intermediate 43 (3.31 g, 13.40 mmol) in dry pyridine (18 mL) under an inert atmosphere at 0° C. was added benzyl chloroformate (2.30 mL, 16.08 mmol) then allowed to warm to ambient temperature and stirred for 18 hours. After concentrating in vacuo the residue was partitioned between Et2O (150 mL) and 1M aqueous HCl (20 mL). The organic phase was dried (MgSO4), filtered and evaporated to a yellow solid. Purification by chromatography through silica gave the title compound (3.50 g, 68%) as an off white solid; 1H NMR (CDCl3) δ1.03-1.12 (2H, m), 1.35-1.46 (2H, m), 1.74-1.82 (5H, m), 2.17-2.18 (2H, m), 2.33-2.39 (1H, m), 3.61 (3H, s), 5.12 (2H, s), 6.50 (1H, s), 7.06 (2H, d), 7.19-7.34 (7H, m)

1. concentrationAfter concentrating in vacuo the residue
2. customwas partitioned between Et2O (150 mL) and 1M aqueous HCl (20 mL)
3. dry with materialThe organic phase was dried (MgSO4)
4. filtrationfiltered
5. customevaporated to a yellow solid
6. customPurification by chromatography through silica