2-Hydrazinopyridine → (3-isobutyl-5-methyl-1-pyridin-2-yl-1H-pyrazol-4-yl)-acetic acid ethyl ester

Participants

Reaction Steps

Combine 3-acetyl-6-methyl-4-oxoheptanoic acid ethyl ester (3.0 g, 13.1 mmol) and pyridin-2-yl-hydrazine (1.72 g, 15.72 mmol) in glacial acetic acid (25 mL) and stir at room temperature for 68 hr. Concentrate to an oil and partition the residue between ethyl acetate (150 mL) and saturated aqueous sodium bicarbonate solution (50 mL). Separate the organic layer, dry (sodium sulfate), filter and concentrate. Purify using silica gel chromatography, eluting with 90:10 hexanes:ethyl acetate, to give (3-isobutyl-5-methyl-1-pyridin-2-yl-1H-pyrazol-4-yl)-acetic acid ethyl ester (3.35 g, 85%). 1H-NMR (400 MHz, CDCl3) δ 8.38 (m, 1H), 7.77 (m, 2H), 7.13 (m, 1H), 4.12 (q, 2H), 3.41 (s, 2H), 2.98 (d, 2H), 2.27 (s, 3H), 1.82 (m, 1H), 1.22 (t, 3H), 0.80 (d, 6H).

Provenance & Evidence