反应详情

To a solution of potassium hydroxide (640 mg, 10 mmol) in methanol (6 mL) at 0° C. was added 2-ethyl-2-thiopseudourea (1.85 g, 10 mmol). The mixture was warmed to room temperature, stirred for 5 min, then filtered off potassium bromide under N2. The filtrate was cooled down to 0° C. then ethyl (ethoxymethylene)cyanoacetate (420 mg, 2.5 mmol) was added. The mixture was gradually warmed to room temperature and stirred for 20 h. The solvent was removed under reduced pressure, and the crude material was purified by flash chromatography using 4% 2M NH3 in MeOH/CH2Cl2 system to obtain 288 mg of the title compound. Mass spectrum 181 (EI, M+).

1. filtrationfiltered off potassium bromide under N2
2. temperatureThe filtrate was cooled down to 0° C.
3. temperatureThe mixture was gradually warmed to room temperature
4. stirringstirred for 20 h
5. customThe solvent was removed under reduced pressure
6. customthe crude material was purified by flash chromatography