Water → 8-Bromo-2-(difluoromethoxy)-6-methylquinoxaline

Participants

Reaction Steps

Tetrabutylammonium bromide (689 mg, 2.14 mmol) and sodium hydroxide (17.1 g of a 50% aqueous solution, 214 mmol) were added to a solution of the title compound of Step D (5.11 g, 21.4 mmol) in dioxane (250 mL) at room temperature. Chlorodifluoromethane was condensed with a cold finger trap and added to the reaction mixture until the mixture was saturated. The reaction mixture was allowed to stir at room temperature overnight. The reaction mixture was slowly poured into water. The resulting mixture was extracted with ethyl acetate three times. The combined organic extracts were dried (MgSO4), filtered, and concentrated under reduced pressure to give a dark-brown oil. Flash chromatography of this brown oil on silica gel, eluting with 1:25 ethyl acetate/hexane afforded the title compound of Step E as a light yellow solid melting at 86°-87° C. (3.23 g, 52%). 1H NMR (CDCl3): δ2.57 (s,3H), 7.75 (t, 1H), 7.84 (s, 1H), 7.92 (s, 1H), 8.58 (s, 1H).

Provenance & Evidence