Methotrexate EP Impurity I

Chemical Name: (4S)-4-[[4-[[(2,4-diaminopteridin-6-yl)methyl]methylamino]benzoyl]amino]-5-methoxy-5-oxopentanoic acid (as per EP) ; (S)-4-(4-{[(2,4-Diaminopteridin-6-yl)methyl](methyl)amino}benzamido)-5-methoxy-5-oxopentanoic acid (as per USP)

Synonym: Methotrexate USP Related Compound I ; Methotrexate 1-Methyl Ester (EP)