Stuhies On The Synthesis Of The Key Intermediate 3-exomethylenecepham Sulfoxide Ester

With features of broad spectrum, actively resist bacteria, high efficacy , Cephalosprin get the favor of doctor and patient , and make a huge contribution for human to overcome various bacterial infection. It growing fastlly, its category and output occupy the first place in all kinds of antibiotic. Because its market is broad, so its raw materials become a hot products of the international market. 3-exomethylenecepham sulfoxide ester is an important intermediate. Using penicillin as starting material, we have offered 3-exomethylenecepham sulfoxide ester by four steps reaction through oxidation, esterification, ring opening and ring closing.Different pathways reported in literatures were discussed and criticized. A pathway with moderate conditions, easier handling, and industrial acceptable was suggested. Penicillin G was oxidized with peracetie acid to get Penicillin G sulfoxide ester, and then esterified with p-nitrobenzyl chlorine in the presence of DMF at room temperature, we opening the ring of penicillin successfully in the presence of NCP and stannic chloride, and use SnCl₄·2Et₂O to get the 3-exomethylenecepham sulfoxide ester. We improve the condition of reaction with the presence of aether, nitromethane and hexene .The structures of above-mentioned product were confirmed by IR, ¹HNMR, physics analysis etc to be basically consistent with those of target products.