Yield:1289076-45-4 480 mg

Reaction Conditions:

with hydrazine hydrate in ethanol at 80; for 24 h;

Steps:

27.1 Step 1 : 5-bromo-3-chloro-2-hydrazinylpyridine

NH2. NHCTo a solution of 5-bromo-2,3-dichloropyridine (500 mg, 2,20 mmol) in EtOH (5 mL) was added hydrazine hydrate (0.33 mL, 6.61 mmol) and the reaction mixture was stirred at 80 °C for 24 hours. After completion of the reaction, it was concentrated under reduced pressure at 25 °C. The resulting caide mass was triturated with EtOH (1 mL) at 0 °C. The solid precipitate was filtered, washed with Et20 (2 mL) and dried under reduced pressure to get 480 mg of 5-bromo-3-chloro-2-hydrazinylpyridine. 1H-NMR (400 MHz, DMSO-￡) 5: 8.14 (s, 1 1 1 ).. 7.92 (s, H), 7,86 (s, IH), 4,24 (brs, 2H). LCMS: [ M i l l = 222.1.

References:

WO2019/43635,2019,A1 Location in patent:Page/Page column 52