3-Chloro-1-methyl-1H-pyrazol-5-amine synthesis

Yield:167408-80-2 83%

Reaction Conditions:

with hydrogenchloride in 1,3-dioxane;dichloromethane at 20; for 20 h;

Steps:

4.1.f

f) 3-chloro-1-methyl-1H-pyrazol-5-amine A solution of tert-butyl (3-chloro-1-methyl-1H-pyrazol-5-yl)carbamate (3.1 g, 9.1 mmol) in CH₂Cl₂ (10 ml) was treated with HCl (3 ml, 4N in dioxane). After 16 h stirring at rt, more HCl was added (2 ml, 4N in dioxane). After another 4 h, the solvents were removed under reduced pressure and the residue purified by recrystallization from diethyl ether to yield 1.26 g (83%) of the title compound as a white solid as hydro chloride. [1H-NMR (DMSO-d₆, 360 MHz) δ 7.60-7.10 (br. s, 3H), 5.27 (d, 1H), 3.10 (s, 3H); HPLC-MS Rt_J=0.42 min; [M+H]⁺=131.9, 133.9]

References:

US2012/258973,2012,A1 Location in patent:Page/Page column 52