2-Amino-5-bromo-3-nitropyridine → 5-(4-Fluorophenyl)-3-nitropyridin-2-amine

Participants

Reaction Conditions

Reaction Steps

5.0 g of 2-amino-5-bromo-3-nitropyridine are dissolved in 120 ml of anoxic dioxane under a nitrogen atmosphere. Subsequently, 69 ml of an aqueous sodium bicarbonate solution (2.0 M), 5.4 g of 4-fluorophenyl-boronic acid, and 1.0 g of trans-dichloro-bis(tricyclohexylphosphane)palladium-(II) are added. The reaction mixture is refluxed at 110° C. for 17 hours. Thereafter, the volatile components are removed in vacuo and the remaining residue is redissolved in 2.0 l of a mixture of water/dichloromethane (1:1). The aqueous phase is extracted four times each with 625 ml of dichloromethane. The organic layer is separated, dried using sodium sulfate, and evaporated to dryness to yield a colorless, crude solid. Subsequently, the residue is purified by flash chromatography on silica gel (eluent: toluene/ethyl acetate 20:1) to afford 5.35 g of the title compound as a colorless solid of m.p. 232° C. MS: 234.2 (MH+). TLC: Rf=0.30 (toluene/ethyl acetate 20:1).

Provenance & Evidence