To 1,4-dioxane (30 mL) was added N-BOC-piperazine (2.89 g, 15.51 mmol), 5-bromo-2-chloropyrimidine (2.00 g, 10.34 mmol) and potassium carbonate (2.86 g, 20.68 mmol). The reaction mixture was heated to 110 °C and stirred for 12 hours. After completion of the reaction, the mixture was cooled to room temperature, filtered to remove insoluble material and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography with the eluent of petroleum ether/ethyl acetate (20:1, v/v) to afford tert-butyl 4-(5-bromopyrimidin-2-yl)piperazine-1-carboxylate as a light yellow solid (3.15 g, 88.7% yield). Mass spectrum (ESI, positive ion mode) m/z: 343.1 [M + H]+. 1H NMR (400 MHz, CDCl3) δ (ppm): 8.29 (s, 2H), 3.83-3.66 (m, 4H), 3.56-3.41 (m, 4H), 1.48 (s, 9H).
