Methylamine → 5-Methyl-2-nitro-4,5-dihydropyrazolo[1,5-a]pyrazin-6(7H)-one

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Reaction Steps

To a solution of 146b (1.0 g, 4.0 mmol) in dichloromethane (30 mL) was added a solution of CH3NH2 (1.07 g, 12.0 mmol, 35% in methanol). This reaction mixture was stirred at room temperature for 3 h and diluted with water (30 mL). The organic layer was separated, dried over Na2SO4, and concentrated under reduced pressure. The residual was purified by silica-gel column chromatography eluting with 30:1 dichloromethane/methanol to afford 146c (450 mg, 57%) as a yellow solid. MS-ESI: [M+H]+ 196.9

Provenance & Evidence