lesinurad int

Synthesis

In a 100 mL three-necked round-bottomed flask equipped with a magnetic stirrer and thermometer, 25 mL of N,N-dimethylformamide (DMF) and intermediate (III) (2.67 g, 1-cyclopropyl-4-isothiocyanonaphthalene) were added. After stirring at room temperature until complete dissolution, potassium carbonate (1.45 g) and methyl bromoacetate (1.61 g) were added sequentially. The reaction temperature was controlled at 25°C. After the slow addition, the reaction was continued with stirring for 3 hours. Upon completion of the reaction, 50 mL of water was added to the reaction mixture for dilution, followed by extraction with ethyl acetate (50 mL × 3). The organic phases were combined and the ethyl acetate was removed by concentration using a rotary evaporator. To the concentrated residue, 50 mL of methanol was added and heated to reflux to dissolve the crystals, followed by slow cooling to room temperature for recrystallization. The crystals were collected by filtration and washed with a small amount of cold methanol and dried under vacuum to give 3.22 g of Intermediate (IV) (methyl 2-((4-(4-cyclopropylnaphthalen-1-yl)-4H-1,2,4-triazol-3-yl)thio)acetate) in 99.5% yield.

References

[1] Patent: CN105906576, 2016, A. Location in patent: Paragraph 0070; 0071; 0083; 0084
[2] Patent: WO2014/8295, 2014, A1. Location in patent: Paragraph 0254-0262
[3] Patent: CN105399694, 2016, A. Location in patent: Paragraph 0085; 0086; 0087; 0088
[4] Patent: CN107098866, 2017, A. Location in patent: Paragraph 0079; 0080; 0081; 0082; 0083