Overview: Cephalosporins: Semi-synthetic antibiotics containing cephalosporins in the molecule. It belongs to the β-lactam class of antibiotics and is a derivative of 7-aminocephalosporanoic acid (7-ACA) in the β-lactam class of antibiotics, so they have similar bactericidal mechanisms. This class of drugs can destroy the cell wall of bacteria and kill bacteria during the reproduction period. It has the advantages of wide antibacterial spectrum, strong antibacterial effect, penicillinase resistance, and less allergic reaction than penicillin, which is an important antibiotic with high efficiency, low toxicity and wide clinical application. Cefovicin is a third-generation cephalosporin drug, clinical use of its sodium salt cefvevicin sodium, cefovicin was first successfully synthesized by SmithKline Beecham in 1994, but the production cost is high, and later developed by Pfizer into a pet-specific Chemicalbook drug, in 2006 for the first time in the European Union for the treatment of skin infections in cats and dogs, until 2008 in the United States was allowed to be used for the treatment of skin and soft tissue infections in cats and dogs, At present, it has not been listed in China. Compared with the three cephalosporins that have been used (cefradine, cefpodoxime, ceftiofur), cefvicin has better antimicrobial activity, higher bioavailability, and longer elimination half-life. For the preparation of cefvicin, the preparation method announced by Pfizer is to use penicillin G as raw material, first protect the 2-position hydroxyl group with benzyl chloroformate, then perform ozonation and epoxidation of the 4-position hydroxyl group in turn, and catalyze hydrogenation to remove the CBZ protective group, and then prepare cefviccin through 8-step reactions such as ring-opening amination and amidation. However, the method has a long route, low yield, harsh reaction conditions, high environmental protection requirements, and difficult operation, so it is not conducive to operation and cost saving when used for mass production.