反応 #61104

反応方程式

2-Amino-thiazole-4-carboxylic acid ethyl ester

(2S,3S)-2-[(R)-4-(4-Methoxy-phenyl)-2,5-dioxo-imidazolidin-1-yl]-3-phenyl-N-(4-propionyl-thiazol-2-yl)-butyramide

sodium methoxide

→

2-amino-thiazole-4-carboxylic acid methyl ester

溶媒

—

hexanes

methanol

反応条件

後処理

1. 1
   その他The ice bath was removed after 0.5 hours
2. 2
   その他A small amount of isoluble material was removed by filtration and to the yellow solution
3. 3
   workup.ADDITIONwas added saturated aqueous ammonium chloride
4. 4
   濃縮the reaction mixture concentrated
5. 5
   その他to remove excess methanol
6. 6
   抽出extracted with 1:1 ether/tetrahydrofuran (3×200 mL)
7. 7
   洗浄The combined organic extracts were washed with water
8. 8
   乾燥The organic solution was dried over sodium sulfate
9. 9
   濃縮concentrated
10. 10
    その他to give a pale yellow solid which
11. 11
    ろ過filtered on a 5.5 cm funnel
12. 12
    その他then dried in vacuo

実験手順

2-Amino-thiazole-4-carboxylic acid ethyl ester (38 g) (prepared as described in Example 4) in methanol (400 mL) was cooled in an ice bath and to it was added 25% sodium methoxide over 0.5 hours. The ice bath was removed after 0.5 hours. A small amount of isoluble material was removed by filtration and to the yellow solution was added saturated aqueous ammonium chloride and the reaction mixture concentrated to remove excess methanol. The mixture was basified to pH=9.0 with saturated aqueous sodium bicarbonate and extracted with 1:1 ether/tetrahydrofuran (3×200 mL). The combined organic extracts were washed with water. The organic solution was dried over sodium sulfate and concentrated to give a pale yellow solid which still contained some residual solvent. The solid was suspended in hexanes, filtered on a 5.5 cm funnel then dried in vacuo to give 2-amino-thiazole-4-carboxylic acid methyl ester (15.6 g) as a pale yellow solid.

出典