Cesium carbonate → 2-(2H-1,2,3-triazol-2-yl)-5-(trifluoromethyl)benzoic acid

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Reaction Steps

To a solution of 2H-1,2,3-triazole (CAS number 288-36-8; 1.0 g, 10.86 mmol) in DMF (4 ml) at 0-10° C. was added cesium carbonate (4.71 g, 14.49 mmol), copper (I) iodide (68 mg, 0.36 mmol), trans-1-N,2-N-dimethylcyclohexane-1,2-diamine (200 mg, 1.44 mmol) and 2-iodo-5-(trifluoromethyl)benzoic acid (CAS number 702641-04-1; 2.28 g, 7.24 mmol). The reaction was subjected to microwave irradiation at 120° C. for 15 minutes and was then partitioned between ethyl acetate (2×100 ml) and water (50 ml). The aqueous layer was acidified with HCl (aq, 2M) to give pH 2 and the organics were extracted with ethyl acetate (3×100 ml). The combined organics were washed with brine, dried over sodium sulfate and concentrated in vacuo. The resulting residue was purified by column chromatography (silica, 0-3% methanol/DCM) to afford 2-(2H-1,2,3-triazol-2-yl)-5-(trifluoromethyl)benzoic acid (Intermediate 37a; also commercially available CAS number 1384066-81-2). The mixed fractions were further purified by column chromatography (silica, 0-3% methanol/DCM) followed by reverse phase preparative HPLC (eluted with acetonitrile/water containing 0.1% formic acid) to afford 2-(1H-1,2,3-triazol-1-yl)-5-(trifluoromethyl)benzoic acid (Intermediate 37b).

Provenance & Evidence