甲氨蝶呤在制备过程和存储不当条件下均会产生其对映异构体D-MTX。为了加强对甲氨蝶呤原料药的质量控制,本研究以甲氨蝶呤为原料,将羧基成酯后与1,8-二氮杂二环十一碳-7-烯(DBU)在无水乙醇中回流,然后脱去酯基得到消旋化的甲氨蝶呤,对映异构体比例约为1∶1,其结构经1H NMR和MS确证,可以作为甲氨蝶呤质量控制的参照物。 Methotrexate produces its enantiomer, D-MTX, both under the conditions of manufacture and storage. In order to enhance the quality control of methotrexate drug substance, methotrexate was used as the raw material to esterify the carboxyl group with 1,8-diazabicycloundec-7-ene (DBU) Water ethanol and then decarboxylated to give racemic methotrexate, the enantiomeric ratio of about 1: 1, its structure confirmed by 1H NMR and MS, can be used as quality control of methotrexate Reference.