Methanesulfonic Acid → 2-Chloro-3-(2,2,2-trifluoroethoxy)pyridine

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Reaction Steps

A reactor vessel is charged with 3-amino-2-chloropyridine (2.7 g, 21 mmol), 2,2,2-trifluoroethanol (15 g, 150 mmol), methanesulfonic acid (2.02 g, 21 mmol), and magnesium sulfate (3 g). The solution is cooled to the range 0° C. to 5° C. and then the reagent t-butyl nitrite (2.51 g of a 96% solution, 23.4 mmol) is added drop-wise to the vessel maintaining the temperature in the range 0° C. to 5° C. After stirring a few minutes the solution is transferred drop-wise to a reactor vessel containing 2,2,2-trifluoroethanol (20 g, 200 mmol) maintained at 65° C. to 70° C. After cooling the solution it is neutralized with aqueous saturated sodium bicarbonate solution and then extracted with MTBE. The solvent is removed by evaporation to obtain 2-chloro-3-(2,2,2-trifluoroethoxy)pyridine as a crude oil (4.4 g) with an actual yield of 70.1%.

Provenance & Evidence