Hydrazine hydrate (1:1) → (3,5-diethyl-1H-pyrazol-4-yl)acetic acid ethyl ester

Participants

Reaction Steps

Combine 4-oxo-3-propionylhexanoic acid ethyl ester (2.49 g, 11.6 mmol) and hydrazine hydrate (0.70 g, 13.9 mmol) in glacial acetic acid (20 mL) and stir at room temperature for 88 hr. Concentrate to an oil. Partition this residue between ethyl acetate (100 mL) and saturated aqueous sodium bicarbonate solution (50 mL). Separate the organic layer; dry (sodium sulfate), filter and concentrate to provide (3,5-diethyl-1H-pyrazol-4-yl)-acetic acid ethyl ester (2.4 g, 98%). 1H-NMR (400 MHz, CDCl3) δ 8.64 (bs, 1H), 4.08 (q, 2H), 3.35 (s, 2H), 2.61 (q, 4H), 1.21 (m, 9H).

Provenance & Evidence