m-Chloroperbenzoic acid → 3-cyano-1-(3,3,4,4,4-pentafluorobutyl)-1H-pyrazolo[3,4-b]pyridine 7-oxide

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Reaction Conditions

Reaction Steps

1-(3,3,4,4,4-pentafluorobutyl)-1H-pyrazolo[3,4-b]pyridine-3-carbonitrile, as described in Step D of Example 158 (1.818 g, 6.26 mmol) and 3-chloroperbenzoic acid (7.1 g, 31.68 mmol, 77%) in acetic acid (20 mL) were stirred at 75° C. for 6 hours. The reaction was then evaporated under reduced pressure to remove acetic acid. To the residue was added a mixture of hexane/ethyl acetate (2/1, 200 mL total) and the pH adjusted to 7.0˜7.5 with aq. K2CO3 at 0° C. The water layer was extracted with hexane/ethyl acetate (2/1, 2×60 mL). The combined organic layer was dried over MgSO4 and evaporated under reduced pressure. The residue was purified by silica gel column chromatography using hexanes/ethyl acetate eluent to give the desired product as a white solid. 1H NMR (500 MHz, CDCl3): δ 2.86 (m, 2H); 5.44 (t, J=7.3 Hz, 2H); 7.31 (t, J=8.2 Hz, 1H); 7.80 (d, J=8.4 Hz, 1H); 8.38 (d, J=5.1 Hz, 1H). m/z=307.02 (M+H).

Provenance & Evidence