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Lithium hydroxide monohydrate (16.7 g, 398.5 mmol) was added to a solution of 4-(hydroxymethyl)tetrahydropyran-4-carboxylic acid ethyl ester (25.0 g, 132.8 mmol) in 4.5:1 methanol/water (220 mL). The mixture was heated to reflux for 40 minutes and the methanol removed in vacuo by concentration using a bath temperature no higher than 45° C. The aqueous layer was then extracted into diethyl ether (4×100 mL) and the combined ether layers washed twice with 2M sodium hydroxide (15 mL). The combined aqueous base layers were cooled to 0° C., acidified to pH 3.0 with 8M aqueous hydrochloric acid, saturated with solid sodium chloride and extracted with ethyl acetate (8×250 mL). The combined organic layers were dried over magnesium sulfate, concentrated in vacuo. The white fluffy powder residue was recrystallized from the minimum amount of methylene chloride/hexanes to afford pure 4-(hydroxymethyl)tetrahydropyran-4-carboxylic acid (17.05 g, 80%).

1. temperatureThe mixture was heated
2. temperatureto reflux for 40 minutes
3. customthe methanol removed in vacuo by concentration
4. customno higher than 45° C
5. extractionThe aqueous layer was then extracted into diethyl ether (4×100 mL)
6. washthe combined ether layers washed twice with 2M sodium hydroxide (15 mL)
7. extractionextracted with ethyl acetate (8×250 mL)
8. dry with materialThe combined organic layers were dried over magnesium sulfate
9. concentrationconcentrated in vacuo
10. customThe white fluffy powder residue was recrystallized from the minimum amount of methylene chloride/hexanes