培美曲塞二钠PemetrexeddisodiumN-[4-[2-(2-amino-4,7-dihydro-4-oxo-1H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoyl]-L-glutamicaciddisodiumsaltN-[4-[2-(2-氨基-4,7-二氢-4-氧代-1H-吡咯[2,3-d]***-5-基)***]苯甲酰]-L-谷氨酸二钠分子式C20H19N5Na2O6分子量471.37CAS150399-23-8)