反应详情

To a solution of 778 mg (2.48 mmol) of 2-(benzothiazole-6-sulfonyl)-2-methyl-propionic acid ethyl ester in THF/water (1/1, 24 mL) are added 208 mg (4.97 mmol) of lithium hydroxide monohydrate. The reaction is stirred at room temperature for 5 h. The organic solvent is removed under reduced pressure. The basic aqueous layer is washed with diethyl ether (10 mL), then cooled in an ice bath and acidified with 6M aqueous HCl solution to pH 2. The acidic aqueous layer is extracted with ethyl acetate (3×15 mL). The combined organic extracts are dried over Na2SO4 and filtered. Concentration of the filtrate under reduced pressure afforded 686 mg of 2-(benzothiazole-6-sulfonyl)-2-methyl-propionic acid as a pale yellow solid. Yield: 66%; ES-MS: m/z 569 [2M−H]; 1H NMR (250 MHz, DMSO-d6) δ ppm 1.51 (6 H, s), 7.91 (1 H, dd, J=8.68, 1.98 Hz), 8.30 (1 H, d, J=8.68 Hz), 8.79 (1 H, d, J=1.83 Hz), 9.70 (1 H, s);

1. customThe organic solvent is removed under reduced pressure
2. washThe basic aqueous layer is washed with diethyl ether (10 mL)
3. temperaturecooled in an ice bath
4. extractionThe acidic aqueous layer is extracted with ethyl acetate (3×15 mL)
5. dry with materialThe combined organic extracts are dried over Na2SO4
6. filtrationfiltered