Acetic Anhydride → 7-Bromo-1H-pyrazolo[4,3-b]pyridine

Participants

Reaction Conditions

Reaction Steps

To a solution of N-(4-bromo-2-methylpyridin-3-yl)acetamide (0.6 g, 2.62 mmol) in toluene (26.2 ml) was added potassium acetate (0.308 g, 3.14 mmol) and acetic anhydride (0.743 ml, 7.86 mmol). The mixture was stirred for 15 minutes and isopentyl nitrite (0.806 ml, 6.02 mmol) was added and the reaction was heated at 85° C. for 4 hours. The reaction was cooled and partitioned between ethyl acetate (75 mL) and water (75 mL). The organic layer was separated, dried over MgSO4, and concentrated to a brown oil. The oil was purified on silica column chromatography eluted with methanol:dichloromethane (3:97). Concentration of product fractions afforded 7-bromo-1H-pyrazolo[4,3-b]pyridine (90 mg, 0.454 mmol, 17.35% yield) as an amber solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 7.71 (1H, d, J=4.80 Hz) 8.32-8.40 (1H, m) 8.40-8.51 (1H, m) 13.89 (1H, br. s.). MS [M+H] found 197.9.

Provenance & Evidence