IMPROVED METHOD FOR PREPARING AN INTERMEDIATE FOR PREPARING PEMETREXED WITH HIGH PURITY AND METHOD FOR PREPARING PEMETREXED WITH HIGH PURITY BY USING THE INTERMEDIATE

摘要

The present invention relates to an improved method for preparing an intermediate to prepare pemetrexed of high purity, and to a method for preparing pemetrexed of high purity by using the same, and more specifically, to a novel method for manufacturing pemetrexed diethyl ester or salt thereof of high purity which is an intermediate to prepare pemetrexed, and to a method for preparing pemetrexed disodium salt of high purity by using the intermediate.