pivaloyloxymethyl(1R,5S,6S)-2-((3S,5S)-5-(N,N-dimethylcarbamoyl)-1-(isobutyryloxymethyloxycarbonyl)pyrrolidin-3-ylthio)-6-((1R)-1-hydroxyethyl)-1-methylcarbapen-2-em-3-carboxylate
pivaloyloxymethyl(1r,5s,6s)-2-((3s,5s)-5-(n,n-dimethylcarbamoyl)-1-(isobutyryloxymethyloxycarbonyl)pyrrolidin-3-ylthio)-6-((1r)-1-hydroxyethyl)-1-methylcarbapen-2-em-3-carboxylate