Hydrogen Peroxide → 3-METHYLQUINOLINE N-OXIDE

Participants

Reaction Conditions

Reaction Steps

3-Methylquinoline (30.0 mL, 224 mmol) was dissolved in acetic acid (85 mL), and 30% aqueous hydrogen peroxide (30.4 mL) was added. The reaction was stirred at 80° C. for 16 h before cooling in an ice bath. 10% aq Na2SO3 (199 mL, 0.5 equiv) was added followed by sodium iodide (2.358 g, 0.05 equiv). This mixture was stirred for 5 min. A peroxide test strip indicated no peroxide remaining. 5N aq NaOH was then added, keeping the internal temperature below 24° C. A dark color formed, indicating that the solution was basic (tested as pH 10). The solution was extracted with four portions of dichloromethane. The combined organics were dried over MgSO4 and filtered, and the filtrate was concentrated under reduced pressure. Purification by silica gel flash chromatography (methanol/ethyl acetate) gave 3-methylquinoline 1-oxide (Intermediate 3, 32.09 g) as a yellow solid. 1H NMR (400 MHz, CDCl3) δ 8.69 (d, J=8.8 Hz, 1H), 8.42 (s, 1H), 7.77 (d, J=8.2 Hz, 1H), 7.68 (td, J=7.8, 1.1 Hz, 1H), 7.56-7.63 (m, 1H), 7.52 (s, 1H), 2.45 (s, 3H); MS (M+1): 160.2.

Provenance & Evidence