Ethanol → Ethyl 2,5-dibromoisonicotinate
Reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([C:8]([Br:11])=[CH:9][N:10]=1)[C:5]([OH:7])=[O:6].S(=O)(=O)(O)O.[CH2:17](O)[CH3:18]>>[Br:1][C:2]1[CH:3]=[C:4]([C:8]([Br:11])=[CH:9][N:10]=1)[C:5]([O:7][CH2:17][CH3:18])=[O:6]Participants
4
Procedure
A solution of 2,5-dibromoisonicotinic acid (1-1, 5 g, 17.80 mmol) and sulfuric acid (1.23 mL, 23.1 mmol) in ethanol (100 mL) was heated to reflux overnight. After reducing the volume of ethanol by rotary evaporation to approximately ¼ of it's original volume, the crude reaction mixture was partitioned between 2M sodium carbonate solution and EtOAc, separating layers and washing the organic layer with saturated sodium bicarbonate solution and brine. This solution was dried over anhydrous sodium sulfate, filtered and concentrated. The residue was purified by normal phase column chromatography (0 to 50% EtOAc in hexanes) to afford the product (1-2) as a dark oil. ESI+MS [M]+C8H7Br2NO2=308.0.