abstract |
A method of purifying a salt of pemetrexed have a structure of formula (III) by salting-out, wherein if M 3 + is H + , then each of M 1 + and M 2 + is independently H + , Li + , Na + or K + , provided that both of them are not H + ; if M 3 + is Li + , Na + or K + , then each of M 1 + and M 2 + is independently Li + , Na + or K + . |