2-(5-Amino-1H-indazol-1-yl)ethanol synthesis

Yield:885270-96-2 90.94%

Reaction Conditions:

with iron⁽⁰⁾;ammonia hydrochloride in ethanol;lithium hydroxide monohydrate at 100; for 3 h;Inert atmosphere;

Steps:

S153.b Step b)

To a solution of 2- (5-nitroindazol-1-yl) ethanol (0.9 g, 4.34 mmol) , iron (1.94 g, 34.75 mmol) and NH₄Cl (116.18 mg, 2.17 mmol) in EtOH (20 mL) and H₂O (4 mL) was degassed and purged with N₂3 times, and then the mixture was stirred at 100 for 3 h under a N₂atmosphere. The reaction mixture was filtered and the filtrate was concentrated under reduced pressure to give a residue. The residue was purified by flash silica gel chromatography (12 gSilica Flash Column, eluent of 03%DCM: methanol 30 mL/min) . The compound 2- (5-aminoindazol-1-yl) ethanol (700 mg, 3.95 mmol, 90.94%yield, 100%purity) was obtained as a light yellow solid.¹H NMR (400 MHz, CDCl₃) δ ppm 3.56 (br s, 2 H) , 4.07 -4.14 (m, 2 H) , 4.40 -4.46 (m, 2 H) , 6.91 (dd, J=8.78, 2.01 Hz, 1 H) , 6.96 (d, J=1.76 Hz, 1 H) , 7.29 (s, 1 H) , 7.83 (s, 1 H) . LC-MS: (ES) m/z 178.1 (M+H⁺) .

References:

WO2022/28586,2022,A1 Location in patent:Paragraph 0385; 0386