Pleuromutilin salicylic acid ester with antibacterial activity and a method of preparing the same

The method of claim 2, wherein the reaction of the compound of formula (II) with the compound of formula (III) comprises the following steps:

• placing the compound of formula (II) and the compound of formula (III), in a molar ratio of 1:1 to 1:1.3, in a reactor;
• adding an organic solvent and a catalytic amount of triethylamine under a nitrogen atmosphere to obtain a reaction mixture;
• heating the reaction mixture at 20-50° C. for 4-8 hours;
• concentrating the reaction mixture and extracting with ethyl acetate to obtain a crude product;
• and
• purifying the crude product on a fresh silica gel chromatography column with petroleum ether and ethyl acetate as an eluent to obtain the compound of formula (I).