Preparation method of lesinurad

The invention discloses a preparation method of lesinurad. The method comprises: allowing 1-cyclopropylnaphthalene-4-yl isorhodanate and acethydrazide to undergo an addition reaction, allowing the obtained 4-acetyl-1-(4-cyclopropylnaphthalene-1-yl) thiosemicarbazide to undergo a cyclization reaction in the function of an alkali reagent, allowing the obtained 4-(4-cyclopropylnaphthalene-1-yl)-5-methyl-4H-1,2,3-triazole-3-mercaptan and methyl chloroacetate (or methyl bromoacetate) to undergo a condensation reaction, allowing the obtained 2-{[4-(4-cyclopropylnaphthalene-1-yl)-5-methyl-4H-1,2,4-triazole-3-yl]sulfo} methyl acetate to undergo an oxidation reaction, allowing the obtained 5-[(methoxycarbonyl)methylthio]-4-(4-cyclopropylnaphthalene-1-yl)-4H-1,2,4-triazole-3-carboxylic acid undergo a bromination reaction, and carrying out an esterolysis reaction to obtain lesinurad. The method is reasonable and simple in technical route, simplified in operation and low in cost. The method is green and eco-friendly and