4-Bromopyrazole → Ethyl 2-[(4-bromo-1H-pyrazol-1-yl)methyl]cyclopropanecarboxylate

Participants

Reaction Conditions

Reaction Steps

A reaction mixture of ethyl 2-{[(methylsulfonyl)oxy]methyl}cyclopropanecarboxylate (880 mg; 4.0 mmol), 4-bromopyrazole (4-2, 588 mg, 4.0 mmol) and NaH 60% in mineral oil (240 mg, 6.0 mmol) with 3.0 mL of DMF was formed. The resulting mixture was stirred at 90° C. under N2 for four hours. The reaction mixture was partitioned between EtOAc (200 mL) and saturated NaHCO3 solution (2×50 mL); brine (50 mL). The organic layer was dried (Na2SO4), then concentrated by vacuum to afford 812 mg of (4-3) as a yellow oil (74%). 1H NMR (400 MHz, chloroform-D) δ ppm 0.85 (dd, J=7.96, 3.16 Hz, 1H) 0.88-0.98 (m, 1H) 1.18-1.29 (m, 3H) 1.56-1.71 (m, 1H) 1.79-1.94 (m, 1H) 3.96-4.08 (m, 2H) 4.07-4.17 (m, 2H) 7.45 (d, J=3.79 Hz, 2H). LCMS calcd for C10H13BrN2O2 (M+H) 274, found 274. HPLC purity 95%.

Provenance & Evidence