Acetic Acid → 4-Thiophen-2-yl-2h-pyrazol-3-ylamine

Participants

Reaction Steps

Hydrazine hydrate [7803-57-8] (4.8 mL, 99.0 mmol) then acetic acid [64-19-7] (5.6 mL, 97.8 mmol) were added to a solution of 3-oxo-2-thiophen-2-yl-propionitrile (7.4 g, 49.0 mmol) in ethanol (100 mL). The solution was then heated to reflux for 2 h. The cooled reaction was evaporated to dryness and the resultant solid triturated in water. Product was isolated by filtration, washed with water, and dried to provide 4-thiophen-2-yl-2H-pyrazol-3-ylamine as 7.1 g of fine off white powder, mp. 183-1840° C. 1H NMR (400 MHz, DMSO-d6) δ ppm 2.51 (s, 1 H) 7.01-7.10 (m, 2 H) 7.27 (dd, J=5.05, 1.01 Hz, 1 H). 13C NMR (100 MHz, DMSO-d6) δ ppm 121.07, 121.47, 127.58, 135.85. LRMS (ESI) m/z 166.0 [(M+H)]+, calc'd for C7H7N3S: 165.22.

Provenance & Evidence