反应详情

To a solution of thiourea (4.5 g) and sodium acetate (5 g) in a mixture of tetrahydrofuran (50 ml) and water (15 ml) was added ethyl 3-chloro-4-(2-pyridyl)-2,4-dioxo-butyrate hydrochloride (5.6 g). After the mixture was stirred at 45° C. to 50° C. for 2 hours, water (50 ml) was added thereto. The resulting mixture was acidified to pH 1.0 with 10% hydrochloric acid. The precipitate was collected by filtration. The precipitate was added to a mixture of water and ethyl acetate, and adjusted to pH 6.0 with 10% potassium carbonate. The separated ethyl acetate layer was washed with brine, dried over magnesium sulfate, and evaporated in vacuo. The residue was recrystallized from a mixture of ethyl acetate and tetrahydrofuran to give ethyl 2-amino-5-(2-pyridinecarbonyl)-4-thiazolecarboxylate (1.1 g).

1. filtrationThe precipitate was collected by filtration
2. additionThe precipitate was added to a mixture of water and ethyl acetate
3. washThe separated ethyl acetate layer was washed with brine
4. dry with materialdried over magnesium sulfate
5. customevaporated in vacuo
6. customThe residue was recrystallized from a mixture of ethyl acetate and tetrahydrofuran