Hydrogen Bromide → 2-Bromo-3-nitrophenol

Participants

Reaction Conditions

Reaction Steps

(Prepared by a modification of reported procedure, J. Org. Chem. 1988, 53, pp 1170-1176). To 2-amino-3-nitro-phenol (24.9 mmol, 1.0 eq.) in 24 mL of water and 12 mL of 1,4-dioxane at reflux, was added 13 mL of HBr (48% aq.) over 10 minutes. The resulting solution was refluxed for an additional 15 minutes, and cooled 0-5° C. A solution of sodium nitrite (24.4 mmol, 0.98 eq.) in 20 mL of water was added over 10 minutes, and stirred for 15 minutes. The reaction mixture was then heated to 60° C. for 15 minutes, and allowed to cool naturally to room temperature, and stirred for 16 hours. The reaction mixture was then extracted with two portions of diethyl ether, and the combined ethereal layers washed with brine, dried over magnesium sulfate, filtered through a layer of celite and concentrated. The residue was diluted with dichloromethane (with ˜0.1% MeOH), and purified via silica gel plug filtration with dichloromethane to yield 2-bromo-3-nitro-phenol (I-8, X═Br) as a pale orange-brown solid. Yield: 50%. 1H NMR (400 MHz; CDCl3): 6.07 (s, 1H), 7.25 (dd, J=8.4, 1.2 Hz, 1H), 7.37 (t, J=8.0 Hz, 1H), 7.48 (dd, J=8.0, 1.6 Hz, 1H) ppm.

Provenance & Evidence