Dimethyl Sulfoxide → 5-(2,2-Difluoroethyl)-2-nitro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine

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Reaction Conditions

Reaction Steps

A sealed tube equipped with a magnetic stirrer was charged with 1-(2-bromoethyl)-5-(bromomethyl)-3-nitro-1H-pyrazole 124c (632 mg, 2.0 mmol), 2,2-difluoroethanamine (486 mg, 6.0 mmol), and DMSO (5 mL). It was heated at 120° C. for 2 h. The mixture was cooled to room temperature and diluted with water (20 mL). The resulting mixture was extracted with ethyl acetate (3×20 mL). The combiner organic layer was dried and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by silica-gel column chromatography eluting with 50:1 dichloromethane/methanol to afford 135a (371 mg, 80%) as a yellow solid. MS-ESI: [M+H]+ 233.2

Provenance & Evidence