Preparation method for topiroxostat

The invention belongs to the field of medicine and chemical engineering, and particularly relates to a preparation method for topiroxostat. 2-chloro-4-[(5-pyridine-4-yl)-1H-[1,2,4]triazole-3-yl]-pyridine is subjected to a cyanation reaction under the action of a cyanation reagent in the presence of a catalyst, base and a ligand to obtain topiroxostat. The preparation method comprises the following steps: 4-cyanopyridine-N-oxide is taken as a starting material, 1,2-dichloroethane is taken as a solvent, triethylamine is taken as base, phosphorus oxychloride is used as a chlorinated reagent, and chlorination is conducted to obtain 2-chloro-4-cyanopyridine; 2-chloro-4-cyanopyridine and isoniazide are in a methanol solvent, sodium methoxide is taken as a catalyst, and close-loop condensation is performed to obtain 2-chloro-4-[(5-pyridine-4-yl)-1H-[1,2,4]triazole-3-yl]-pyridine. The preparation method has the advantages that a safe and cheap cyanogroup source is selected, a hypertoxic cyanation reagent is avoided, the environmental harm is reduced, the product yield is high, the purity is high, and the suitability for industrial mass production is high.