Hydrochloric Acid → Lesinurad

Participants

Reaction Conditions

Reaction Steps

A solution of lithium hydroxide (98 mg, 4.1 mmol) in water (10 mL) was added dropwise over 5 mins to a solution of methyl 2-(5-bromo-4-(1-cyclopropylnaphthalen-4-yl)-4H-1,2,4-triazol-3-ylthio)acetate (prepared as described in example 1 above; 1.14 g, 2.7 mmol) in ethanol (10 mL) and THF (10 mL) at 0° C. The mixture was stirred at 0° C. for a further 45 mins and then neutralized to pH 7 by the addition of 0.5N HCl solution at 0° C. The resulting mixture was concentrated in vacuo to ⅕th of its original volume, then diluted with water (˜20 mL) and acidified to pH 2-3 by the addition of 0.5N HCl to produce a sticky solid. (If the product comes out as an oil during acidification, extraction with DCM is recommended.) The tan solid was collected by vacuum filtration and dried under high vacuum at 50° C. for 16 h in the presence of P2O5 to yield 2-(5-bromo-4-(1-cyclopropylnaphthalen-4-yl)-4H-1,2,4-triazol-3-ylthio)acetic acid (1.02 g, 93%).

Provenance & Evidence