Synonyms: 1-Azabicyclo[3.2.0]hept-2-ene-2-carboxylicacid,3-[[(3S,5S)-5-[[(3-carboxyphenyl)amino]carbonyl]-3-pyrrolidinyl]thio]-6-[(1R)-1-hydroxyethyl]-4-methyl-7-oxo-,monosodium salt, (4R,5S,6S)- (9CI);1-Azabicyclo[3.2.0]hept-2-ene-2-carboxylicacid,3-[[5-[[(3-carboxyphenyl)amino]carbonyl]-3-pyrrolidinyl]thio]-6-(1-hydroxyethyl)-4-methyl-7-oxo-,monosodium salt, [4R-[3(3S*,5S*),4a,5b,6b(R*)]]-;