Preparation method of Ataluren

The invention discloses a preparation method of Ataluren. The preparation method comprises an addition step in which under an alkaline condition, 3-cyanobenzoate reacts with hydroxylamine hydrochloride by using a first mixed solvent to obtain an intermediate as shown in a formula III, a condensation step in which in a first organic solvent, a condensation reaction is conducted on the intermediate shown in the formula III and o-fluorobenzoic acid to obtain an intermediate shown in a formula IV, a cyclization step in which in a second organic solvent, catalyzing is conducted by using Lewis acid, and intramolecular dehydration is conducted on the intermediate in the formula IV to obtain an intermediate in a formula V, and an ester hydrolysis step in which under an alkaline condition, ester hydrolysis is conducted on the intermediate in the formula V by using a second mixed solvent to obtain the product. Cheap raw materials are subjected to addition, condensation, cyclization and ester hydrolysis, the reaction co