3,5-Dibromopyridine → Tert-butyl 4-(5-bromopyridin-3-yl)piperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of the 3,5-dibromo-pyridine (12.8 g, 68.8 mmol) and piperazine-1-carboxylic acid tert butyl ester (10 g, 42.4 mmol) in 200 mL of dioxane was treated with Pd2(dba)3 (5 g, 5.5 mmol), 2-(di-tbutyl-phosphino)biphenyl (4 g, 13.4 mmol), and sodium t-butoxide (7.2 g, 75 mmol). The reaction was heated to 95° C. for 8 h then cooled and filtered through celite. The mixture was evaporated and the residue was purified by flash column chromatography on silica gel, eluting with a solvent gradient of 1:4 ethyl acetate/hexane to 100% ethyl acetate. Recovered 2.9 g of product (20%). MS (ESI) m/z 344 (M+H)+.

Provenance & Evidence