关键词: 苯乙酰氨基氯甲基头孢烷烯酸对甲氧基苄酯，苯乙酰氨基吡啶甲基头孢羧酸对甲氧苄酯，合成，动力学，溶剂效应

Abstract:

7-Phenylacetamido-3-pyridiniummethylcephem-4-carboxylic acid p-methoxybenzyl ester was prepared by reaction of GCLE with pyridine. The reaction process was inspected by HPLC in dichloromethane,acetone, tetrahydrofuran, the mixture of ethyl acetate and DMF. It was determined that the nucleophilic substitution reaction was 2nd order reaction. In a given solvent the rates can be perfectly related with Arrhenius's equation within the experimental temperature of 25℃and 35℃.The activation energy and the preexponential factor according to Arrhenius's equation were gained,and the solvent effects were discussed.The order of the nucleophilicity in different solvents was as follows: the mixture of ethyl acetate and DMF＞dichloromethane＞tetrahydrofuran＞acetone.

Key words: phenylacetamidochloridecephemcarboxylic acid p-methoxybenzyl ester iodid, phenylacetamidopyridiniummethylcephemcarboxylic acid p-methoxybenzyl ester,synthesis,kinetics,solvent effect