7-酰胺基-3-卤甲基-3-头孢烯-4-羧酸酯是制备第二代和第三代头孢菌素的重要中间体,其合成方法很多。专利文献报道了用N-溴代琥珀酰亚胺、N-溴代乙酰胺等溴代试剂对3-甲基-3-头孢烯-1-氧化物的酯进行光催化卤化反应的几种方法。这些溴代方法缺少选择性,除在C-3位甲基上发生卤代反应外,C-2位、7-酰胺侧链以及酯基团上均可发生卤代反应,得到许多不希望要的卤化物。近来,日本专利报道了一个选择性高且有效的新溴化方法,即用N-溴代琥珀酰亚胺在醋酸中,于20℃通氮下,对2′,2′,2′-三氯 7-Amido-3-halomethyl-3-cephem-4-carboxylate is an important intermediate for the preparation of second- and third-generation cephalosporins. There are many synthetic methods. Patent literature reports several methods for the photocatalytic halogenation of esters of 3-methyl-3-cephem-1-oxide with bromine reagents such as N-bromosuccinimide and N-bromoacetamide . These methods of bromination lack selectivity and, except for the halo reaction at the C-3 methyl group, halogenation can occur at the C-2 position, the 7-amide side chain and the ester group, resulting in many undesired Of halides. Recently, the Japanese patent reports a highly selective and effective neobromination method using N-bromosuccinimide in acetic acid at 20 ° C for 2 ’, 2’, 2’-tris chlorine