Carbon Dioxide → 1-cyclopentyl-1H-pyrazole-4-carboxylic acid

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Reaction Steps

Using the procedure of Example B30, 4-bromo-1-cyclopentyl-1 H-pyrazole (9.0 g, 42 mmol), n-BuLi (2.5 M, 18.5 mL, 46.2 mmol) and CO2 were combined to provide 1-cyclopentyl-1 H-pyrazole-4-carboxylic acid (3.5 g, 47% yield). 1H NMR (400 MHz, DMSO-d6): δ 8.31 (s, 1H), 7.85 (s, 1 H), 4.78 (m, 1 H), 1.70-2.56 (m, 8 H); MS (ESI) m/z: 181.1 [M+H]+.

Provenance & Evidence