Potassium Carbonate → 4-(4-Chloro-2-methoxyphenyl)pyridine 1-oxide

Participants

Reaction Conditions

Reaction Steps

4-Chloropyridine-N-oxide (500 mg, 3.85 mmol), 2-methoxy-4-chlorophenylboronic acid (862 mg, 4.63 mmol) and K2CO3 (1.59 g, 11.55 mmol) were suspended in DMSO (5 mL) and PdCl2(dppf) (314 mg, 0.385 mmol) was added. The reaction mixture was placed under vacuum for 20 min and flushed with N2. This process was repeated, and the reaction mixture was heated at 120° C. for 3 h. The reaction mixture was cooled to 25° C. and partitioned between methylene chloride and 5% lithium chloride. The aqueous phase was removed, and the organic phase was washed with brine, dried over Na2SO4, filtered and concentrated to dryness under reduced pressure. Flash chromatography (ISCO 40 g column, methylene chloride/MeOH 100:0 to 90:10) provided the title compound (673 mg, 74%) as a tan solid: 1H NMR (300 MHz, CD3OD) δ 8.21 (dd, J=5.4, 1.8 Hz, 2H), 7.47 (dd, J=5.6, 1.6 Hz, 2H), 7.26 (d, J=8.2 Hz, 1H), 7.06 (dd, J=8.3, 2.4 Hz, 1H), 7.00 (d, J=1.7 Hz, 1H), 3.87 (s, 3H); ESI MS m/z 235 [M+H]+.

Provenance & Evidence