1-(2-(pyrrolidin-1-yl)ethyl)-1H-pyrazol-4-amine synthesis

Yield: 82%

Reaction Conditions:

with hydrogen;palladium 10% on activated carbon in ethanol under 1551.49 Torr; for 2 h;

Steps:

219.219b
A mixture of 4-nitro-l-(2-pyrrolidin-l-yl-ethyl)-lH-pyrazole (4.40 g, 20.9 mmol), ethanol (100 mL) and 10% palladium on carbon (0.41 g, 30.7 mmol) was hydrogenated in a Paar shaker at 30 psi under hydrogen for 2 h. The reaction mixture was filtered over diatomaceous earth and the filtrate was evaporated in vacuo. l-(2-Pyrrolidin-l-yl-ethyl)- lH-pyrazol-4-ylamine was isolated as an orange oil, which became a dark gummy material upon standing at room temperature (3.10 g, 82%). ¹H NMR (400 MHz, CDCl₃, δ, ppm): 7.15 (s, IH), 7.08 (s, IH), 4.14 (t, J=7.00 Hz, 2H), 2.88 (t, J=6.97 Hz, 4H), 2.52 (s, 4H), 1.765 (s, 4H). MS = 181 (MH)+.

References:

CEPHALON, INC.;CURRY, Matthew A.;DORSEY, Bruce D.;DUGAN, Benjamin J.;GINGRICH, Diane E.;MESAROS, Eugen F.;MILKIEWICZ, Karen L. WO2010/141796, 2010, A2 Location in patent:Page/Page column 295