反应详情

3-Chlorocarbonyl-propionic acid methyl ester (4.4 g, 21 mmol) is added dropwise to a stirred suspension of thiosemicarbazide (4.0 g, 44 mmol) in THF (25 ml) at 0° C. After stirring at room temperature for 18 h the product which precipitates is removed by filtration and washed with diethyl ether. This product (7.1 g, 34 mmol) is suspended in toluene (30 ml) at 0° C. and methane sulfonic acid (3.37 ml, 52 mmol) is added dropwise to the stirred reaction. The reaction is heated at 70° C. for 3 hours then concentrated at reduced pressure. Methanol (30 ml) is added followed by slow addition of aqueous ammonia, with stirring, until the solution is basic. The titled compound which precipitates is removed by filtration and purified by chromatography on silica, eluting with chloroform-methanol (10:1).

1. customprecipitates
2. customis removed by filtration
3. washwashed with diethyl ether
4. temperatureThe reaction is heated at 70° C. for 3 hours
5. concentrationthen concentrated at reduced pressure
6. additionMethanol (30 ml) is added
7. additionfollowed by slow addition of aqueous ammonia
8. stirringwith stirring, until the solution
9. customThe titled compound which precipitates
10. customis removed by filtration
11. custompurified by chromatography on silica
12. washeluting with chloroform-methanol (10:1)