Cefoperazone Dimer Impurity 65

(2R) -2- ((S) -2- (4-ethyl-2,3-dioxopiperazine-1-carboxamido) -2- (4-hydroxyphenyl) acetamido) -2- (1- ((6R,7R) -7- ((S) -2- (4-ethyl-2,3-dioxopiperazine-1-carboxamido) -2- (4-hydroxyphenyl) acetamido) -3- (((1-methyl-1H-tetrazol-5-yl) thio) methyl) -8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carbonyl) -7-oxo-1,2,5,7-tetrahydro-4H-furo[3,4-d][1,3]thiazin-2-yl) acetic acid