1-(3,4-DICHLORO-BENZYL)-1H-PYRAZOL-4-YLAMINE synthesis

Yield:895929-62-1 40%

Reaction Conditions:

Stage #1: 1-[(3,4-dichlorophenyl)methyl]-4-nitro-1H-pyrazolewith water;tin(ll) chloride in ethanol;Heating / reflux;
Stage #2: with water;sodium hydrogencarbonate in ethanol at 20;

Steps:

7

Intermediate 7: 1-r(3,4-Dichlorophenyl)methyll-1 H-pyrazol-4-amine; To a solution of 1-[(3,4-dichlorophenyl)methyl]-4-nitro-1 H-pyrazole (Intermediate 1 ) (1.3 g, 4.79 mmol) in EtOH (35 mL) was added SnCI₂.2H₂O (5.39 g, 23.98 mmol) and the mixture was stirred at reflux overnight. After cooling at room temperature, the mixture was poured into water and basified with a saturated solution of NaHCO₃. The aqueous phase was extracted with EtOAc and the organic phase was washed with brine, dried over Na₂SO₄, filtered and evaporated under reduced pressure. The residue was purified by flash column chromatography eluting with CH₂CI₂/Me0H: 95/5 to give the title compound as a colorless oil (0.46 g, 40%). LC/MS: m/z 242 (M+H)⁺, Rt : 2.53 min.

References:

WO2008/74824,2008,A2 Location in patent:Page/Page column 36