5-Hydroxy-2-methylpyridine-1-oxide (22.33 g, 178.45 mmol) was suspended in acetic anhydride (250 ml). The clear yellow mixture was then stirred at reflux (150°C) for 3 h, causing a colour change to dark brown-black. The solution was cooled to ambient temperature and the solvent was removed under reduced pressure to leave a dark brown-black liquid, which was dried overnight in vacuo at 50°C. Yield = 36.59 g, 174.90 mmol, 98%.

¹H NMR (400 MHz, 298 K, DMSO) δ_H 8.39 (1H, d, ⁴J_HH = 2.5 Hz, Py), 7.65 (1H, dd, ³J_HH = 8.5 Hz, ⁴J_HH = 2.5 Hz, Py), 7.49 (1H, d, ³J_HH = 8.5 Hz, Py), 5.14 (2H, s, CH₂), 2.31 (3H, s, CH₃), 2.11 (3H, s, CH₃).

¹³C{¹H} NMR (100 MHz, 298K, DMSO) δ_C 170.0 (C=O), 169.0 (C=O), 152.9 (Py), 146.4 (Py), 142.7 (Py), 130.3 (Py), 122.4 (Py), 65.6 (CH₂), 20.7 (CH₃), 20.6 (CH₃).

MS (ESI) m/z 210.1 [M+H]⁺, 232.1 [M+Na]⁺.

IR v cm^-1 2946 w, 1765 m, 1738 s, 1581 w, 1485 m, 1436 w, 1370 m, 1182 s, 1024 s, 925 m, 898 m, 856 m, 722 w, 670 w.

Elemental Analysis found (Calculated for C₁₀H₁₁NO₄) % C 57.46 (57.41), H 5.52 (5.30), N 6.63 (6.70).