Yield:913839-67-5 53%

Reaction Conditions:

with hydrazine hydrate in ethanol at 120;

Steps:

Preparation 51 5-bromo-2-hydrazinyl-4-methylpyridine

Preparation 51 5-bromo-2-hydrazinyl-4-methylpyridine [0237] Combined 5-bromo-2-chloro-4-methylpyridine (15.0 g, 72.46 mmol) and EtOH (60 mL) and added hydrazine hydrate (85%, 45 mL) and stirred at 120°C overnight. The reaction mixture was concentrated to give a residue which was extracted with EtOAc (50 mLx2) and water (50 mLx2). Then combined organic layers were extracted with brine, dried over Na₂S0₄ to and concentrated to give a residue which was purified by flash chromatography (petroleum ether: EtOAc =10: 1 tol :5) to give the title compound (7.8 g, 53%).

References:

WO2014/160810,2014,A1 Location in patent:Paragraph 0236; 0237