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

Yield:89088-55-1 75%

Reaction Conditions:

with hydroxylamine hydrochloride;potassium hydroxide in ethanol;waterReflux;

Steps:

1-10.3
Step 3; To a solution of hydroxylamine hydrochloride (3.06 g) in ethanol (20 mL), a solution of potassium hydroxide (1.26 g) in water-ethanol (1:1, 40 mL), and 63 (2.3 g, 9 mmol) were added. The solution was then refluxed overnight. The reaction mixture was then concentrated. The resulting residue was purified by silica gel column chromatography (ethyl acetate/petroleum ether 1:5) to yield 64 as a white solid (1.45 g, y. 75%). LC/MS (Method D): 0.58 min, [M+H]⁺ = 175.99, 178.01. ¹H-NMR (300 Mz) (DMSO): 3.44 (d, J = 93.5 Hz, 3H), 4.77 (s, 2H), 5.53 (s, 1H).

References:

Shionogi & Co., Ltd. EP2426135, 2012, A1 Location in patent:Page/Page column 117

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