反应详情

To a solution of succinic acid monoethyl ester (22.0 g) and triethylamine (16.8 g) in tetrahydrofuran (150 ml) was added dropwise chloroethyl formate (18.0 g) at −20° C. After stirring for 30 min., pulverized thiosemicarbazide (13.7 g) was added and the mixture was stirred at room temperature for 7 hrs. Water was added to the reaction mixture, acidified with 2N hydrochloric acid and extracted with chloroform. The aqueous layer was separated and sodium chloride was added. The mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4) and concentrated. The residual crystals were recrystallized from dichloromethane-ethanol to give ethyl 4-[2-(aminocarbothioyl)hydrazino]-4-oxobutanoate as colorless prism crystals (8.23 g, 25%). melting point: 143–144° C.

1. additionwas added
2. stirringthe mixture was stirred at room temperature for 7 hrs
3. extractionextracted with chloroform
4. customThe aqueous layer was separated
5. additionsodium chloride was added
6. extractionThe mixture was extracted with ethyl acetate
7. washThe ethyl acetate layer was washed with saturated brine
8. dry with materialdried (MgSO4)
9. concentrationconcentrated
10. customThe residual crystals were recrystallized from dichloromethane-ethanol