Pemetrexed Disodium: C~20~H~19~N~5~Na~2~O~6~. Mw: 471.37. (1) L-Glutamic acid, N-[4-[2-(2-amino-4,7-dihydro-4-oxo-1H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoyl]-, disodium salt; (2) Disodium N-[p-[2-(2-amino-4,7-dihydro-4-oxo-1H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoyl]-L-glutamate. CAS-150399-23-8; CAS-137281-23-3 (pemetrexed)(2004).