Preparation method of letermovir intermediate

The invention relates to a preparation method of a letermovirintermediate, which comprises the following steps: reacting o-fluoroaniline with paraformaldehyde and hydrogen chloride gas in an acidic solvent to obtain a compound I; adding the compound I into an alcohol solvent, and adding urotropine for reaction to obtain a compound II; adding the compound II into a toluene solvent, and then adding phenyl chloroformate for reaction to obtain a compound III; reacting the compound III with trimethyl phosphonoacetate in a tetrahydrofuran solution to obtain a compound IV; reacting the compound IV with 2-methoxy-5-trifluoromethylaniline under the action of a catalyst to obtain a compound V; and adding a solvent and organic alkali into the compound V, and reacting the compound V to obtain a compound TM. According to the invention, o-fluoroaniline is used as a raw material, and a target product, namely the letermovir intermediate TM, is obtained through a reaction. The adopted raw materials are low in price, use of tr