Cornforth reagent → Toluene-4-sulfonic acid 5-acetyl-1H-pyrazol-3-yl ester

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Reaction Steps

To toluene-4-sulfonic acid 5-[(S)-1-hydroxyethyl]-1H-pyrazol-3-yl ester (6.09 g, 21.6 mmol) in anhydrous dichloromethane (180 ml) was added pyridinium dichromate (9.74 g, 25.9 mmol) and the resulting slurry was stirred at room temperature for 17.6 h. The mixture was poured directly onto a column of silica gel, which was eluted with ethyl acetate to yield 5.13 g (85%) of the title compound as a whitish solid: 1H NMR (360 MHz, DMSO-d6) δ 2.43 (3H, s), 2.45 (3H, s), 6.78 (1H, s), 7.49 (2H, d, J=8.2 Hz), 7.80 (2H, d, J=8.3 Hz), 13.72 (1H, s); MS (ES+) m/e 281 [M+H]+.

Provenance & Evidence