((1R,5S,6S)-6((R))-1-hydroxyethyl-2-((3S,5S)-5(S-methyl-4-thiomorpholin ylcarbonyl)pyrrolidin-3-thio))-l-methylcarbapen-2-em-3- carboxylic acid
((1r,5s,6s)-6((r))-1-hydroxyethyl-2-((3s,5s)-5(s-methyl-4-thiomorpholin ylcarbonyl)pyrrolidin-3-thio))-l-methylcarbapen-2-em-3- carboxylic acid