反应详情

To a solution of ethyl 2-ethylthiazole-5-carboxylate (400 mg, 2.159 mmol) in MeOH (10 mL) is added 1N NaOH (6 mL, 6 mmol) After stirring at room temperature for 18 hours, the crude is concentrated under reduced pressure to remove MeOH. The crude is diluted with EtOAc, the organic layer is washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure to give 2-ethylthiazole-5-carboxylic acid (282.4 mg). HPLC retention time=0.78 minutes (condition D); MS (m+3)=160.4; 1H NMR (400 MHz, CD3OD) δ ppm 1.40 (t, J=7.6 Hz, 3H) 3.07 (q, J=7.6 Hz, 2H) 5.08 (br. s., 1H) 8.20 (s, 1H).

1. concentrationthe crude is concentrated under reduced pressure
2. customto remove MeOH
3. additionThe crude is diluted with EtOAc
4. washthe organic layer is washed with brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure