Sodium Carbonate → methyl 2-[2-(5-bromo-1-methyl-1H-pyrazol-4-yl)-2-oxoethyl]-2-formylhydrazinecarboxylate

Participants

Reaction Steps

Methyl 2-{[(4-methoxybenzyl)amino]methylene}hydrazinecarboxylate (3.28 g, 13.8 mmol), 2-bromo-1-(5-bromo-1-methyl-1H-pyrazol-4-yl)ethanone (3.90 g, 13.8 mmol) and sodium carbonate (1.16 g, 13.8 mmol) were combined in a mixture of N,N-diisopropylethylamine (99.5%, 2.30 mL, 13.8 mmol) and acetonitrile (30 mL). The reaction was heated at 80° C. for 18 hours, at which time water was added, and heated was continued for 10 minutes. After removal of solvent in vacuo, the aqueous residue was partitioned between water and ethyl acetate (100 mL). The aqueous layer was extracted with ethyl acetate (4×100 mL), and the combined organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure. Purification using silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane) provided the product (1.20 g), contaminated with some impurities. This material was taken directly to the following step. LCMS m/z 319.0 (M+1). 1H NMR (400 MHz, CD3OD) δ, product peaks: 3.74 (s, 3H), 3.92 (s, 3H), 4.82 (br s, 2H), 8.14 (s, 1H), 8.24 (s, 1H).

Provenance & Evidence