Tetrahydropyran-2-methanol → Oxane-2-carboxylic acid

A solution of tetrahydropyran-2-methanol (15.63 g, 135 mmol) in DCM (280 mL) are cooled to 0° C. TEMPO (0.25 g, 1.59 mmol) is added, followed by Aliquat 336 (2.8 g, 6.93 mmol) and 0.5 M aqueous KBr solution (27 mL, 13.5 mmol). Under vigorous stifling a solution of NaOCl/water (pH 8.6, 960 mL) and NaHCO3 (57.6 g) is added dropwise. The reaction is allowed to warm to room temperature and stirred for 18 h. Sodium hydroxide (15 g) is added and the reaction mixture is washed with DCM (2×100 mL). The basic aqueous layer is carefully acidified with concentrated aqueous HCl solution (150 mL) and then extracted with ethyl acetate (8×250 mL). The combined organic extracts are dried (MgSO4), filtered and the filtrate is concentrated under reduced pressure to give a pale yellow oil, which is purified by distillation under reduced pressure (bp 144-146° C., 25 Torr) to give 6.74 g of tetrahydro-pyran-2-carboxylic acid. Yield: 35%; 1H NMR (250 MHz, CHLOROFORM-d) δ ppm 1.45-1.77 (4 H, m), 1.79-2.19 (2 H, m), 3.44-3.67 (1 H, m), 3.93-4.18 (2 H, m), 9.62 (1 H, br. s.)

1. additionis added dropwise
2. washthe reaction mixture is washed with DCM (2×100 mL)
3. extractionextracted with ethyl acetate (8×250 mL)
4. dry with materialThe combined organic extracts are dried (MgSO4)
5. filtrationfiltered
6. concentrationthe filtrate is concentrated under reduced pressure
7. customto give a pale yellow oil, which
8. distillationis purified by distillation under reduced pressure (bp 144-146° C., 25 Torr)

ORD record

ord-622d99220d8c491486af7380262f28d7

Source dataset

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08349871B2