反应详情

Ethyl 3-bromo-2-oxobutanoate (Intermediate 177, 12.2 g; 58.7 mmol) and thiourea (4.46 g; 76.1; 58.7 mmol) were combined and heated to reflux. The solution was allowed to cool to room temperature and stir for 12 hours. The reaction was monitored by LC/MS. The base was precipitated with 20% NH4OH (10 ml) and then redissolved with 1N HCl (100 ml) and then finally reprecipitated with 20% NH4OH. The precipitate was collected and washed with H2O. The crude product was then crystallized from 9:1 ethanol/water to give 5.95 g of product in 55% yield. MS (ES) MH+: 187 for C7H10N2O2S.

1. temperatureheated to reflux
2. customThe base was precipitated with 20% NH4OH (10 ml)
3. dissolutionredissolved with 1N HCl (100 ml)
4. customfinally reprecipitated with 20% NH4OH
5. customThe precipitate was collected
6. washwashed with H2O
7. customThe crude product was then crystallized from 9:1 ethanol/water