Sodium Hydroxide → 3-hydroxy-1-(2-pyridyl)-1H-pyrazole

Participants

Reaction Steps

(2E)-3-Ethoxy-N′-pyridin-2-ylprop-2-enohydrazide (8.5 g, 41 mmol) was stirred with concentrated 37% HCl (20 mL) for 3 h. The resulting reaction mixture was adjusted to pH 7 using 1N NaOH (aq) and a precipitate formed. The reaction mixture then extracted with EtOAc (3×50 mL)and washed with brine. The combined organic phase was dried over Na2SO4, concentrated in vacuo purified using liquid chromatography on silica gel eluting with EtOAc (100%) to afford 1-pyridin-2-yl-1,2-dihydro-3H-pyrazol-3-one as a yellow solid. 1H NMR (CD3Cl, 300 MHz) δ 12.00 (br, 1H), 8.43˜8.39 (m, 2H), 7.85 (ddd, 1H), 7.64 (d, 1H), 7.16 (ddd, 1H), 5.99 (d, 1H). MS (ESI) 162 (M++H).

Provenance & Evidence