Acetic Anhydride → 4-ethoxy-1H-pyridin-2-one

Temperature

25 °C

A mixture of 4-ethoxypyridine 1-oxide (5 g, 35.9 mmol) in acetic anhydride (36.7 g, 359 mmol) was heated to reflux for 4 h. Then the solvent was removed in vacuo, and the residue was dissolved in MeOH (25 mL) and H2O (25 mL) and stirred at 25° C. for 16 h. The mixture was concentrated. The crude material was purified by silica column chromatography (DCM/MeOH=10:1). All fractions found to contain product by TLC (DCM/MeOH=10:1, Rf=0.6) were combined and concentrated to yield a dark yellow solid of 4-ethoxypyridin-2-ol (2.5 g, 16.17 mmol, 45.0% yield): 1H NMR (400 MHz, CD3OD) δ 7.28 (d, J=7.6 Hz, 1H), 6.07 (d, J=3.2, 7.2 Hz, 1H), 5.86-7.85 (d, J=2.4 Hz, 1H), 4.06-4.01 (m, 2H), 1.38 (t, J=7.2 Hz, 3H); ES-LCMS m/z 140.0 (M+H).

1. temperaturewas heated
2. temperatureto reflux for 4 h
3. customThen the solvent was removed in vacuo
4. dissolutionthe residue was dissolved in MeOH (25 mL)
5. concentrationThe mixture was concentrated
6. customThe crude material was purified by silica column chromatography (DCM/MeOH=10:1)
7. concentrationconcentrated

ORD record

ord-18704d0bc37d4fce810e5260abf81e18

Source dataset

uspto-grants-2015_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09035063B2