Phosphorus oxychloride → 4-Chloro-6-(3,4-dimethoxyphenyl)pyrazolo[1,5-a]pyrazine

Participants

Reaction Conditions

Reaction Steps

6-(3,4-dimethoxyphenyl)pyrazolo[1,5-a]pyrazin-4(5H)-one 5.02 (74 mg, 0.27 mmol) was taken up in phosphorous oxychloride (1.4 mL, 15 mmol) and mixture was heated to 95° C. for two hours. After cooling to room temperature, mixture was carefully added via pipet to vigorously stirring water (15 mL) with internal temperature monitoring, at a rate to keep the internal temperature below 45° C. Reaction flask was washed with 15 mL of ethyl acetate and added to aqueous mixture to ensure complete transfer. Layers were separated and aqueous was extracted with ethyl acetate. Combined organic layers were washed with 1:1 brine/saturated NaHCO3 (aq), dried (Na2SO4), filtered, and concentrated under reduced pressure to yield 4-chloro-6-(3,4-dimethoxyphenyl)pyrazolo[1,5-a]pyrazine 5.03. LCMS-ESI+ (m/z): [M+H]+ calcd for C14H13ClN3O2: 290.06; found: 290.10.

Provenance & Evidence