Ertapenem Dimer Amide Impurity

(4R,5S,6S)-3-(((3S,5S)-5-((3-((2S,3R)-5-carboxy-2-((1S,2R)-1-carboxy-2-hydroxypropyl)-4-(((3S,5S)-5-((3-carboxyphenyl)carbamoyl)pyrrolidin-3-yl)thio)-3-methyl-2,3-dihydro-1H-pyrrole-1-carbonyl)phenyl)carbamoyl)pyrrolidin-3-yl)thio)-6-((R)-1-hydroxyethyl)-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid