2-Bromo-5-nitropyridine → 1-[4-(5-Nitro-2-pyridinyl)-3-butynyl]-4-(2-pyridinyl)piperazine

Participants

Reaction Steps

A solution of 2-bromo-5-nitropyridine (3.11 g, 0.015 mol) and the alkyne prepared in Step (a) (3.0 g, 0.014 mol) in 5.8 mL of triethylamine and 60 mL of acetonitrile is degassed by bubbling in dry nitrogen for 15 minutes, and 0.2 g (0.0003 mol) of bis(triphenylphosphine)palladium chloride and 0.05 g (0.0003 mol) of cuprous iodide are added. The flask is flushed with nitrogen and the mixture is stirred at room temperature for 5 hours. The solvent is removed under reduced pressure, and the residue is partitioned between 50 mL of dichloromethane and 50 mL of saturated aqueous sodium bicarbonate. The aqueous layer is extracted with 30 mL of dichloromethane and the combined organic layers are washed with water and dried (sodium sulfate), and the solvent is removed in vacuo. The residue is chromatographed (silica gel, 1% methanol/ 99% dichloromethane) to give the title compound as a brown solid; mp 126°-126.5° C.

Provenance & Evidence