Ethylhydrazine → 1,3-Diethyl-5-methylpyrazole

Participants

Reaction Steps

A solution of 18.9 g (0.2 mol) of hex-4-yn-3-one (from Step B) in 120 mL of n-butanol was treated with 40 mL (0.227 mol) of ethyl hydrazine, 34% solution in water. The resulting mixture was heated at reflux for 1.5 h, then cooled to rt. The mixture was concentrated to ˜150 μL volume; this was partitioned between 1 L of ether and 250 mL of water. The layers were separated and the organic layer was dried and concentrated to afford the title compound, which was used without further purification. 1H-NMR (400 MHz) δ 1.22 (t, J=7.6, 3H), 1.37 (t, J=7.2, 3H), 2.23 (s, 3H), 2.59 (q, J=7.6, 2H), 4.01 (q, J=7.2, 2H), 5.81 (s, 1H).

Provenance & Evidence