Hydrogen Peroxide → 3-(Trifluoromethyl)[1,2,4]triazolo[4,3-a]pyrazine 7-oxide

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Reaction Conditions

Reaction Steps

A mixture of 250 mg (1.33 mmol) of 3-(trifluoromethyl)[1,2,4]triazolo[4,3-a]pyrazine (Intermediate 6, Step A), 0.479 mL (4.66 mmol) of 30% hydrogen peroxide aqueous solution, and 2 mL of glacial acetic acid was stirred at 95° C. After 8 h, the solution was cooled and concentrated. The residue was partitioned between dichloromethane and saturated sodium bicarbonate aqueous solution. Thin-layer chromatography on silica gel (90:10:1 dichloromethane:methanol:concentrated ammonium hydroxide solution) revealed that the product was in the aqueous phase. Therefore, the aqueous solution was concentrated to dryness, and the residue was purified by preparative HPLC (C18 reverse phase column, 0-50% acetonitrile in water containing 0.05% trifluoroacetic acid) to provide the title compound as a white solid. LC-MS 205 (M+1).

Provenance & Evidence