反应详情

To a suspension of 6.6 mM of 3-[(acetyloxy)methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid sodium salt in 35 ml of dimethyl formamide (DMF) is added 2 equivalents of p-pivalyloxybenzyl alcohol followed by cooling to 0° C after which 7.2 mM of dicyclohexylcarbodiimide in 7.5 ml of DMF is added dropwise with stirring. The mixture is stirred at 0° C for one hour and an additional four hours at room temperature. The formed dicyclohexylurea is removed by filtration. The filtrate is diluted with chloroform, washed with water, dried over magnesium sulfate, filtered, and evaporated in vacuo to give 3-[(acetyloxy)methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid p-pivalyloxybenzyl ester.

1. additionis added dropwise
2. stirringThe mixture is stirred at 0° C for one hour and an additional four hours at room temperature
3. customThe formed dicyclohexylurea is removed by filtration
4. additionThe filtrate is diluted with chloroform
5. washwashed with water
6. dry with materialdried over magnesium sulfate
7. filtrationfiltered
8. customevaporated in vacuo