반응 #61104

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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

용매

—

hexanes

methanol

반응 조건

후처리

1. 1
   기타The ice bath was removed after 0.5 hours
2. 2
   기타A 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
   농축the reaction mixture concentrated
5. 5
   기타to remove excess methanol
6. 6
   추출extracted with 1:1 ether/tetrahydrofuran (3×200 mL)
7. 7
   세척The combined organic extracts were washed with water
8. 8
   건조The organic solution was dried over sodium sulfate
9. 9
   농축concentrated
10. 10
    기타to give a pale yellow solid which
11. 11
    여과filtered on a 5.5 cm funnel
12. 12
    기타then dried in vacuo

실험 절차

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.

출처