反应 #355179

反应方程式

N,O-bis(trimethylsilyl) acetamide

diethoxyphosphinylisothiocyanate

ampicillin

→

penicillanic acid

溶剂

dichloromethane

dichloromethane

反应条件

后处理

1. 1
   其他a clear solution was obtained
2. 2
   workup.STIRRINGthe reaction mixture was further stirred at 5°C for 150 minutes
3. 3
   其他A small amount of precipitate was formed
4. 4
   其他The layers were separated and as the organic layer
5. 5
   萃取the aqueous layer was extracted once with 75 ml of ethyl acetate at pH 7.0
6. 6
   浓缩concentrated to some extent in vacuo in order
7. 7
   其他to remove dichloromethane
8. 8
   workup.ADDITIONsubsequently treated with n-hexane until a precipitate
9. 9
   其他was formed
10. 10
    过滤filtered off
11. 11
    洗涤washed with n-hexane
12. 12
    其他dried in vacuo to constant weight

实验过程

0.75 ml (about 3 mmol) of N,O-bis(trimethylsilyl) acetamide was added under anhydrous conditions, to a suspension of 1.05 g (3 mmol) of D(-) 6-α-amino-benzylcarbonamidopenicillanic acid (anhydrous D(-) ampicillin) in 50 ml of dry dichloromethane and after 30 minutes stirring at about 20°C, a clear solution was obtained. Then, a solution of 0.6 g (3 mmol) of diethoxyphosphinylisothiocyanate [(C2H5O)2P(O)NCS] in 10 ml of dichloromethane was added at 0°-5°C over a period of 10 minutes and as the reaction did not cause a rise in temperature, the reaction mixture was further stirred at 5°C for 150 minutes. A small amount of precipitate was formed and according to thin-layer chromatograms, ampicillin was no longer present in the reaction mixture. The reaction mixture was poured into 75 ml of ice-water and the pH was brought to 7.0. The layers were separated and as the organic layer did contain part of the desired penicillin, the aqueous layer was extracted once with 75 ml of ethyl acetate at pH 7.0. The organic layers were combined, concentrated to some extent in vacuo in order to remove dichloromethane, and subsequently treated with n-hexane until a precipitate was formed, which was vacuum filtered off, washed with n-hexane and dried in vacuo to constant weight to obtain 0.5 g (30%) of D-6-[α-{3-diethoxyphosphinyl)-thioureido}benzylcarbonamido]-penicillanic acid.

来源