A mixture of 2-bromobenzo[4,5]imidazo[1,2-a]pyrimidine (40 mg, 0.2 mmol), pent-4-yn-1-ol (22 mg, 0.26 mmol), tetrakis(triphenylphosphine)palladium (23 mg, 0.02 mmol), DIPEA (50 mg, 0.4 mmol) in 2 mL dioxane was heated at 120° C. for 20 min in a microwave reactor and then cooled to rt. It was diluted with EtOAc (20 mL) and washed with brine (30 mL) and water (2×30 mL) and concentrated. The residue was purified by silica chromatography (EtOAc in DCM, 10% to 100%) to afford 5-(benzo[4,5]imidazo[1,2-a]pyrimidin-2-yl)pent-4-yn-1-ol as a yellow solid (28 mg, 56%). 1H NMR (400 MHz, CDCl3): δ 8.68 (d, J=6.8, 1H), 8.03 (d, J=8.4 Hz, 1H), 7.86 (d, J=8.4 Hz, 1H), 7.57 (m, 1H), 7.42 (m, 1H), 6.95 (d, J=6.8 Hz, 1H), 3.85 (t, J=6 Hz, 2H), 2.82 (t, J=6.8 Hz, 2H), 1.93 (m, 2H); MS (ESI) m/z [M+H]+252.
