3-Chloro-1H-pyrazol-5-aMine synthesis

Yield:916211-79-5 87%

Reaction Conditions:

with hydrogenchloride;tin(II) chloride dihdyrate in methanol at 20; for 6 h;

Steps:

3-Chloro-lH-pyrazol-5-amine (4):
Tin (II) chloride (12.8 g, 68 mmol) was added in portions to a solution of 3-chloro-5-nitro- lH-pyrazole (2.0 g, 13.6 mmol) in methanol (200 mL) and cone. HCl (10 mL) at 0 °C. The reaction mixture was stirred at room temperature for 6 hours, and the organic solvent was removed under reduced pressure. The residue was diluted with water (20 mL), neutralized to pH 7 with Na2C03, then extracted with EtOAc (3 x 50 mL). The combined organic phases were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated to give the title compound (1.4 g, 87%), which was used without further purification. 1H NMR (400 MHz, DMSO-d₆): δ 11.55 (bs, 1H), 5.26 (s, 2H), 5.21 (s, 1H).

References:

CORNELL UNIVERSITY;DANA-FARBER CANCER INSTITUTE, INC.;CHILDREN'S MEDICAL CENTER CORPORATION;MELNICK, Ari, M.;GABAS, Lorena, Fontan;US, Ilkay;CASALENA, Gabriella;GRAY, Nathanael, S.;SCOTT, David, A.;HATCHER, John;DU, Guangyan;WU, Hao;QIAO, Qi WO2018/85247, 2018, A1 Location in patent:Paragraph 00296; 00300

FullText