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

Participants

Reaction Steps

To a suspension of 42.1 mg of (5R,6S)-6-((1R)-1-hydroxyethyl)-2-(imidazo[5,1-b]thiazol-3-yl)-1-carbapen-2-em-3-carboxylic acid 10 ml of water was added 1.3 ml of a 0.1 N aqueous sodium hydrogen carbonate solution, and the mixture was stirred at room temperature for 1 hour to form a solution, which was then lyophilized. The lyophilized product was dissolved in 1 ml of dry DMF, 0.034 ml of iodomethyl pivalate was added under the atmosphere of argon at −30° C., and the mixture was stirred for 1.5 hours during which the temperature was raised up to −10° C. The reaction mixture was diluted with 20 ml of ethyl acetate, and washed with semi-saturated aqueous saline. The organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to a volume of 3 ml, The residue thus obtained was purified by column chromatography on silica gel (chloroform:methanol=15:1) and on Sephadex LH-20 (chloroform:methanol=1:1) in this sequence to give 27.2 mg of the title compound.

Provenance & Evidence