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ChemicalBook CAS DataBase List 2-Hydroxy-5-methylpyridine
1003-68-5

2-Hydroxy-5-methylpyridine synthesis

9synthesis methods
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%.
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Yield:1003-68-5 46%

Reaction Conditions:

Stage #1: 2-Bromo-5-methylpyridinewith potassium tert-butylate in tert-Amyl alcohol at 100; for 40 h;Schlenk technique;Inert atmosphere;
Stage #2: with formic acid at 20; for 24 h;

Steps:



General procedure: In a dry Schlenk tube 2-bromo-6-methylpyridine (5.98 g, 35.0 mmol) was dissolved in 100 mL oft-AmylOH and KOt-Bu (39.3 g , 350.0 mmol) was added. The mixture was stirred at 100 °C for 40 h. The solvent was removed under reduced pressure and the residue was dissolved in 50 mL of HCO2H. The solution was stirred for 24 h at rt, then the pH was set to about 6 using 3N aq. KOH solution. The extraction was performed using CHCl3 (3×) and the combined organic phases were washed with brine, dried over MgSO4, filtered and evaporated. The residue was transferred to a column chromatography (8%MeOH in DCM) to afford 1 (white solid), 2.75 g (72%).

References:

Wysocki, Jedrzej;Schlepphorst, Christoph;Glorius, Frank [Synlett,2015,vol. 26,# 11,art. no. ST-2015-B0171-L,p. 1557 - 1562] Location in patent:supporting information

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