Potassium Hydroxide → 3-Bromo-2-(4-nitrophenylazo)-5-hydroxypyridine

Participants

Reaction Steps

5-Bromo-3-pyridinol from Example 12b (8.7 g, 0.050 mmol) and KOH (1.1 g, 19.6 mmol) were dissolved in water (200 mL). A suspension of p-nitrobenzenediazonium tetrafluoroborate (11.8 g, 0.50 mol, prepared as described in J. Org. Chem., 44: 1572-15783 (1979)) was added. The reaction was stirred for 1 hour, diluted with acetic acid (50 mL) and filtered. The crude product was allowed to air dry, then chromatographed (silica gel; chloroform/methanol, 95:5-90:10) to provide the title compound (5.45 g, 34% yield): MS (CI/NH3) m/z 323, 325 (M+H)+ ; NMR (DMSO-d6, 300 MHz) δ 8.48-8.43 (m, 2H), 8.21 (d, J=2.4 Hz, 1H), 8.09-8.06 (m, 2H), 7.72 (d, J=2.4 Hz, 1H).

Provenance & Evidence