a novel process for the preparation of ceftiofur , a cephalosporin antibiotic useful in the treatment of bovine respiratory disease using a novel bromo or chloro intermediate . the process comprises of the steps of cyclizing a new bromo or chloro intermediate with thiourea in the presence of selected solvents to produce ceftiofur of high purity . a process to prepare such novel bromo and chloro intermediate comprising of the steps of condensing silylated furaca with 4 -- 2 methoxyamino - 3 - oxobutyric acid or its acid halide is also described .