Chitosan quinolone derivative as well as preparation method and application thereof

The invention relates to the field of medicine and agriculture, in particular to a chitosan quinolone derivative and a preparation method and application thereof. The structural formula of the derivative is as shown in formula I; the preparation method comprises the following steps: by taking chitosan as a raw material, carrying out ion exchange on the chitosan and carboxylate of a quinolone compound to obtain a derivative shown in a formula I; or taking chitosan as a raw material, and carrying out acylation reaction on the chitosan and the activated quinolone compound to obtain the derivative shown in the formula 1. The method has the advantages of cheap and easily available raw materials and simple preparation method. The antibacterial activity of the chitosan derivative prepared by the method is higher than that of chitosan, the toxicity of the chitosan derivative is lower than that of quinolone drugs, the reaction conditions are green and harmless, the yield is high, and the chitosan derivative can be wid