反应详情

To a solution of methyl ester of example 19.1 (513 mg) in 12.5 ml THF:water (4:1) was added sodium hydroxide (75 mg). The reaction mixture was stirred at room temperature for 3 hours before adding 2 ml of methanol. The reaction was stirred overnight before evaporation of the solvent in vacuo. The aqueous layer was extracted with ethyl acetate before being acidified. It was then extracted several times with ethyl acetate. The combined organic layers were dried over sodium sulfate and concentrated to afford the title acid (452 mg) as a yellow solid. 1H-NMR (CDCl3, 400 MHz): 8.55 (s, 1H), 8.05 (s, 1H), 7.50 (m, 2H), 7.45 (m, 1H), 4.35 (d, 1H), 4.00 (d, 1H).

1. stirringThe reaction was stirred overnight before evaporation of the solvent in vacuo
2. extractionThe aqueous layer was extracted with ethyl acetate
3. extractionIt was then extracted several times with ethyl acetate
4. dry with materialThe combined organic layers were dried over sodium sulfate
5. concentrationconcentrated