Sulfuric Acid → 2-Ethylpyrazolo[1,5-a]pyridine

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Reaction Conditions

Reaction Steps

2-Ethylpyrazolo[1,5-a]pyridine-3-carboxylic acid (4.1 g, 22 mmol) was stirred in water (100 mL) and sulfuric acid (2.5 mL) was added. The mixture was heated at 70° C. for 2 h and cooled to 20° C. The mixture was poured into ethyl acetate and neutralized with saturated sodium bicarbonate. The extracts were separated and the aqueous layer was extracted with ethyl acetate. The combined extracts were dried (sodium sulfate) and evaporated to give the desired compound (2.6 g, 82%). LCMS for C9H11N2 (M+H)+: m/z=147.1. 1H NMR (300 MHz, DMSO-d6): δ 8.52 (m, 1 H), 7.57 (m, 1 H), 7.11 (m, 1 H), 6.75 (m, 1 H), 6.38 (s, 1 H), 2.73 (m, 2 H), 1.22 (m, 3 H).

Provenance & Evidence