Patent ID: 8278445

Claim:
A method for preparing a compound of general formula (I), wherein R 1 is 6-(2-cyanophenoxypyrimidin)-4-yl or pyrimidin-4-yl substituted by a halogen atom at site 6, the method comprising the steps of: (1) reacting a compound of general formula (II) with a formylating agent in an aprotic solvent in the presence of a Lewis acid at a temperature ranging from −20° C. to 200° C., and adding an organic base to promote the reaction so that an intermediate product is obtained, wherein R 1 has the same definition as R 1 in general formula (I); (2) isolating the intermediate product produced by step 1; (3) reacting the isolated intermediate product obtained in step (2) with a methylating agent in the presence of an alkali at a temperature ranging from −20° C. to 100° C. to obtain the compound of general formula (I).