Synthesis method of chloramphenicol intermediate

The invention relates to a synthetic method of a chloramphenicol intermediate, and belongs to the technical field of drug intermediate synthesis. In order to solve the problem that the existing reaction product nitration is not easy to control, the invention provides a synthetic method of a chloramphenicol intermediate, which comprises the following steps: carrying out acylation reaction on a compound shown as a formula I and thionyl chloride to obtain a compound shown as a formula II; and carrying out diazotization reaction on the compound in the formula II and diazomethane in an ether solvent to generate diazoketone, and then adding haloid acid to carry out bromination reaction to obtain a chloramphenicol intermediate product compound in a formula III. The synthesis route provided by the invention has the advantages of few side reactions, high product conversion rate, short reaction route and environmental friendliness, and the new synthesis route also avoids the generation of nitrides and more effectively