Hydrazine hydrate (1:1) → 2-(3-pyridin-3-yl-4,5-dihydro-1H-pyrazol-5-yl)phenol

Participants

Reaction Conditions

Reaction Steps

A solution of (2E)-3-(2-hydroxyphenyl)-1-pyridin-3-ylprop-2-en-1-one (12.5 g, 55.6 mmol), hydrazine monohydrate (6.00 mL, 123 mmol), and ethanol (160 mL) was allowed to stir at 80° C. overnight. The reaction mixture was filtered over a pad of celite and washed with MeOH and DCM. The resulting filtrate was concentrated to give 2-(3-pyridin-3-yl-4,5-dihydro-1H-pyrazol-5-yl)phenol (12.5 g, 94%) as a light grey solid. 1H NMR (400 MHz, d6-DMSO, HCl salt) δ: 9.52-9.67 (bs, 1H), 8.78 (s, 1H), 8.45-8.51 (m, 1H), 7.97 (d, 1H), 7.61 (s, 1H), 7.38 (t, 1H), 7.26 (d, 1H), 7.07 (t, 1H), 6.81 (d, 1H), 6.76 (t, 1H), 5.04 (t, 1H), 3.44 (dd, 1H), and 2.76 (dd, 1H). LCMS: (FA) ES+ 240.2, ES-238.5.

Provenance & Evidence