Dimethyl Sulfoxide → 6-Chloro-4-methoxy-pyrazolo[1,5-a]pyrazine

Participants

Reaction Conditions

Reaction Steps

Crude 6-chloro-4-methoxypyrazolo[1,5-a]pyrazine-3-carboxylic acid from above (611 mg, 2.68 mmol) was dissolved along with palladium(II) trifluoroacetate (401 mg, 1.2 mmol) in DMF (24 mL). DMSO (1.6 mL) and TFA (2 mL, 26 mmol) were added and the resulting mixture was heated to 110° C. After stirring 2.5 h, the reaction mixture was cooled and filtered. The filtrate was concentrated in vacuo and was partitioned between EtOAc, saturated aqueous NaHCO3 and water. The phases were separated, and the aqueous phase was extracted with EtOAc. The combined organic phase was washed with water and was dried over Na2SO4, filtered, and concentrated. The concentrate was purified by silica gel (5-30% EtOAc in hexanes) to provide 6-chloro-4-methoxypyrazolo[1,5-a]pyrazine 5.36. LCMS-ESI+ (m/z): [M+H]+ calcd for C7H7ClN3O: 184.0; found: 184.2.

Provenance & Evidence