Cefixime Impurity B (E-isomer)

2-(((E)-(1-(2-aminothiazol-4-yl)-2-((((2R)-5-methyl-7-oxo-2,4,5,7-tetrahydro-1H-furo[3,4-d][1,3]thiazin-2-yl)methyl)amino)-2-oxoethylidene)amino)oxy)acetic acid