2-Hydroxy-5-methylpyridine (cas# 1003-68-5) is a useful compound for organic synthesis. In particular it has been used for the diastereoselective preparation of cyclobutane-fused pyridinyl sulfonyl fluorides. 2-hydroxy-5-methylpyridine and Iodobenzene were the impurities present in Pirfenidone (PFD) drug substance. PFD is a novel antifibrotic agent approved for mild to moderate Idiopathic pulmonary fibrosis (IPF) as orphan drug[1].
3-cyano-6-hydroxypyridine and sodium lauryl sulfate were added to a mixed solvent of n-butanol and water. Subsequently, the temperature was raised to 50 °C., and sulfuric acid water obtained by dissolving 98% sulfuric acid in water was added dropwise at the temperature. After stirring for about 20 minutes, the mixture was cooled to room temperature, and 5% Pd / C was added. The system was replaced with hydrogen, and hydrogenation was carried out at atmospheric pressure for 6 hours. After the reaction was completed, the catalyst was removed by filtration, and the solution was washed with 10% sodium hydroxide aqueous solution. After partially neutralizing to H = 5 and extraction with n-butanol, a solution of crude 3-methyl-6-hydroxypyridine in butanol was obtained. When this solution was quantified by liquid chromatography, the pass-through rate was 99.2%, and the yield of 2-hydroxy-5-methylpyridine was 83%.
[1] Suresh Babu Bodempudi, ;K. S. Reddy, Ravichandra Babur. “Development and Substantiation of a RP-HPLC Method for Monitoring of Impurities in Pirfenidone Drug Substance.” 美国分析化学(英文) 6 1 (2015): 1019–1029.
