7-Amino-3-methyl-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid → (Pivaloyloxy)methyl (6R-trans)-7-amino-3-methyl-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylate

Participants

Reaction Steps

To 35 ml of dimethylformamide is added 7.5 g of the sodium salt of 7-amino-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid and the solution is stirred at room teemperature for about 30 minutes after which 8 ml of chloromethylpivalate is added. Stirring is continued at room temperature for about 3 hours. The mixture is diluted with ethylacetate and washed with water. The organic layer is separated, evaporated to dryness, and the residue is recrystallized from ethylacetate to give 7-amino-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid pivalyloxymethyl ester.

Provenance & Evidence