反应详情

Ester 32 (4.01 g, 10.4 mmol) was dissolved in THF/MeOH/CH3CN mixture (v/v/v, 1/1/1, 90 mL). Lithium hydroxide monohydrate (874 mg, 20.8 mmol) as a solution in water (30 mL) was added, and the mixture stirred overnight. The solvent amount was reduced in vacuo to about 30 mL. To the remaining aqueous solution was added hydrochloric acid (1 M) to bring the pH down to 3. The aqueous layer was extracted with diethyl ether (3×40 mL). The combined organic extracts were dried over sodium sulfate. The drying agent was removed by filtration and the solvents removed using a rotary evaporator. The residue was purified by chromatography on silica gel (120 g RediSep column, eluting with a gradient of 0% through 50% ethyl acetate/hexanes over 60 min, 85 mL/min) to give the product 34 (3.37 g, 89%) as a colorless liquid. 1H NMR (300 MHz, CDCl3) δ 7.22 (d, J=6.1 Hz, 2H), 6.82 (d, J=6.1 Hz, 2H), 4.46 (s, 2H), 3.81 (m, 1H), 3.75 (s, 3H), 2.65-2.49 (m, 2H), 1.80-1.60 (m, 2H), 1.50-1.20 (m, 18H), 0.85 (t, J=5.8 Hz, 3H).

1. extractionThe aqueous layer was extracted with diethyl ether (3×40 mL)
2. dry with materialThe combined organic extracts were dried over sodium sulfate
3. customThe drying agent was removed by filtration
4. customthe solvents removed
5. customa rotary evaporator
6. customThe residue was purified by chromatography on silica gel (120 g RediSep column
7. washeluting with a gradient of 0% through 50% ethyl acetate/hexanes over 60 min