Yield:89284-10-6 44%

Reaction Conditions:

with hydrogen bromide in acetic acid at 20; for 24 h;

Steps:

i Step-i: Synthesis of 3 ,6-dibromo-4-methylpyridazine

A suspension of 3,6-dichloro-4-methylpyridazine (lOg, 61.3 mmol) in 30 - 33% HBr in acetic acid (200 mL) was stined at room temperature for 24h. The precipitate was collected by filtration. The precipitate was suspended in DCM and neutralized with saturated aqueous sodium bicarbonate. The organic layer was separated, washed with brine, dried over anhydrous sodium sulfate and evaporated under reduced pressure to get 3,6-dibromo-4-methylpyridazine (6.8g,44%). ‘H NMR (300 MHz, CDC13): 3 7.50 (d, 1= 1.2 Hz, 1H), 2.41 (d, 1= 0.6 Hz, 3H); LC-MS:253.1 [M+3Hjt

References:

WO2016/185342,2016,A1 Location in patent:Page/Page column 44