Cesium carbonate → 2-[2-Fluoro-5-(trifluoromethyl)phenyl]-4-nitropyridine

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Reaction Steps

10.0 g (0.0481 mol) of 2-fluoro-5-(trifluoromethyl)phenylboronic acid, 6.86 g (0.0433 mol) of 2-chloro-4-nitro-pyridine, 1.10 g (0.0012 mol) of tris(dibenzylideneacetone) dipalladium (0), 0.67 g (0.00289 mol) of di-tert-butyl-trimethylsilylmethyl-phosphane, 15.67 g (0.0481 mol) of cesium carbonate and 100 ml of dioxane were stirred at room temperature for 24 hours. The resultant mixture was poured into 200 ml of water and extracted twice with 200 ml of methylene chloride. The organic phase was dried over magnesium sulfate overnight and filtered. The solvent was removed on a rotovapor and the residue was purified by chromatography on silica gel with petroleum ether/ethyl ether (10/0.5) as eluent. Yield of 2-(2-fluoro-5-trifluoromethyl-phenyl)-4-nitro-pyridine: 3.58 g (28.92%) as a white solid with m.p. 58.11° C. 1H NMR (CD2Cl2) 7.10-8.90 (m, 6H, arom-H). 19F NMR (CD2Cl2) −62.98 (s, 3F, CF3), −111.85 (s,1F, F-arom). LC/MS calculated for C12H6F4N2O2 286.04; found 286.04.

Provenance & Evidence