p-Toluenesulfonic acid → 6-Bromo-3-(2,5-dimethyl-pyrrol-1-yl)-5-trifluoromethyl-pyridine-2-carboxylic acid methyl ester

Participants

Reaction Steps

3-Amino-6-bromo-5-trifluoromethyl-pyridine-2-carboxylic acid methyl ester (Intermediate A4) (2 g, 6.69 mmol) was suspended in toluene (8 ml), then p-toluenesulfonic acid (TsOH) (0.115 g, 0.669 mmol) and acetonylacetone (0.941 ml, 8.03 mmol) was added. The reaction mixture was heated at reflux for 2 hrs and allowed to cool to RT overnight. The resulting dark red/black solution was concentrated in vacuo to remove toluene and the crude residue diluted with 200 ml EtOAc, washed with NaHCO3 (50 ml), dried (MgSO4) and concentrated in vacuo to give a brown solid; LC-MS Rt=5.58 min [M+H]+ 377/379 (Method 10minLC_v002).

Provenance & Evidence