Furan lactone ring derivative and application thereof

The invention provides a compound as shown in a formula I described in the specification or a pharmaceutically acceptable salt or a pro-drug thereof. R1 and R3 are respectively independently selected from H, C1-C4 alkyl and 1-3 halogens; R2 is selected from H, phenyl and substituent phenyl, and the substituent group thereof is halogen or C1-C4 alkyl, wherein when the R2 is the phenyl, the R1 and the R3 are not H simultaneously; or when the R2 is H, the R1 and the R3 are not halogens simultaneously. The invention also provides an application of the compound. The compound disclosed by the invention has certain antimicrobial activity and can be used as a latent antimicrobial drug, thus a new choice is provided for clinical medication.