7β-(D-5-carboxy-5-phthalimidovaleramido)-3-hydroxymethylceph-3-em-4-carboxylic acid di-triethylamine salt 在
sodium chloride 、 magnesium sulfate 作用下,
以
二氯甲烷 为溶剂,
以93.2%的产率得到7β-(D-5-phthalimido-5-carboxyvaleramido)-3-(3-oxobutyryloxy)methyl-3-cephem-4-carboxylic acid