Methanol → Pivaloyloxymethyl (1S,5R,6S)-6-((1R)-1-hydroxyethyl)-2-(imidazo[5,1-b]thiazol-3-yl)-1-methyl-1-carbapen-2-em-3-carboxylate

Participants

Reaction Steps

To a suspension of 32.5 mg of (1S,5R,6S)-6-((1R)-1-hydroxyethyl)-2-(imidazo[5,1-b]thiazol-3-yl)-1-methyl-1-carbapen-2-em-3-carboxylic acid in a mixture of 10 ml of water and 8 ml of methanol was added 7.8 mg of sodium hydrogen carbonate, and the mixture was stirred at room temperature for 10 minutes to form a solution. Methanol was removed under reduced pressure, and the residue was lyophilized. The lyophilized product was dissolved in 2 ml of dry DMF, 0.03 ml of iodomethyl pivalate was added under the atmosphere of argon at −30° C., and the mixture was stirred for 2 hours during which the temperature was raised up to −10° C. Ethyl acetate was added to the reaction mixture, and the mixture was washed with semi-saturated aqueous saline. The organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to a total volume of 3 ml. The residue thus obtained was purified by column chromatography on silica gel (chloroform:methanol=30:1-10:1) to give 26.6 mg of the title compound.

Provenance & Evidence