反应详情

To an ice-cold solution of indoline 11a (219 mg, 1 mmol) dissolved in methylene chloride (5 mL) were added sequentially pyridine (1 mL) and acetic anhydride (0.12 mL, 1.1 mmol), and the resulting mixture was stirred over a range of 0° C. to room temperature for 18 h. The reaction mixture was quenched with water and extracted with methylene chloride. The combined organic extracts were washed with 5% aq. hydrochloric acid and brine then dried (MgSO4). Removal of solvents and chromatographic purification of the residue using 3:7 ethyl acetate:hexanes as eluent gave the acetate 12a (228 mg, 87% yield) as a pale yellow solid. This was recrystallized from hexanes-methylene chloride to afford a colorless solid, mp 128°-130° C. Spectral data: 1H NMR: δ 1.23 (d, 3H, J=7 Hz), 2.04 (s, 3H), 2.10 (s, 3H), 2.17 (s, 3H), 2.31 (s, 3H), 3.61 (dd, 1H, J=10.2, 2.3 Hz), 4.13 (t, 1H, J=9.53 Hz), 7.96 (s, 1H); 13C NMR: δ 12.3, 16.7, 20.4, 20.7, 24.8, 33.9, 57.4, 116.4, 125.7, 129.3, 133.7, 139.5, 144.2, 168.5, 169.1; HRMS: calcd. for C15H20NO3 (M+H+) 262.1443, fnd. 262.1446.

1. customThe reaction mixture was quenched with water
2. extractionextracted with methylene chloride
3. washThe combined organic extracts were washed with 5% aq. hydrochloric acid and brine
4. dry with materialthen dried (MgSO4)
5. customRemoval of solvents and chromatographic purification of the residue