甲氧头孢中间体7-MAC的合成工艺改进

The Process Improvement in the Synthetic Method of Intermediate of Methoxy Cephalosporin 7-MAC

以7-ACA为原料,浓硫酸作催化剂,乙腈为溶剂,与1-甲基-5-巯基-1,2,3,4-四氮唑反应得到中间体7-TMCA,产率为90%;再以二甲基亚砜为溶剂,将新制的二苯基重氮甲烷与7-TMCA在45℃反应5 h,得中间体7-ATCA,产率为92%;7-ATCA与3,5-二叔丁基-4-羟基苯甲醛加热回流得中间体Schiff Base A,产率为95%;Schiff Base A与复合氧化剂B、甲醇反应得Schiff Base B,产率为93%.最后以甲醇-THF-H2O为溶剂,将Schiff Base B与Girard T试剂反应得7-MAC,产率为92%.7-MAC的总收率达到62%,其结构经核磁氢谱及质谱确证.

7-TMCA was synthesized in 90% yield by the reaction of 7-ACA with 1-methyl-5-mercapto-1,2,3,4-tetrazole in the presence of concentrated sulfuric acid as catalyst and acetonitrile as solvent.7-TMCA reacted with the new synthetic diphenyl diazomethane at 45 ℃ for 5 h in the presence of DMSO to prepare 7-ATCA in 92% yield.Then dehydration 7-ATCA of 3,5-ditertbutyl-4-hydroxybenzaldehyde to afford Schiff Base A in 95% yield.Schiff Base B in 93% yield was prepared by the oxidation and addition of Schiff Base A with oxadant B and methanol.Finally,in the presence of CH3CH2OH-THF-H2O,the reaction of Schiff Base B with Girard＇s Reagent T to obtain 7-MAC.Yield： 92%,HPLC purity： 99.20%.The total yield of the title product was 62%（using calculation based on 7-ACA）.The structures of 7-MAC was confirmed by IR,1H NMR and MS spectroscopy.