18591-82-7

Step A: A mixture of 3-chloro-6-methylpyridazine (516 mg, 4.0 mmol), NH4OH (30%, 3 mL), and copper(II) sulfate pentahydrate (26 mg, 0.2 mmol) was stirred for 40 hours at 120 °C. After completion of the reaction, the mixture was cooled to room temperature and partitioned between EtOAc and brine. The aqueous layer was extracted five times with EtOAc. The combined organic phases were dried with anhydrous Na2SO4, filtered and concentrated, and purified by silica gel column chromatography (elution gradient: 0-10% MeOH in CH2Cl2 solution) to afford 6-methylpyridazin-3-amine (160 mg, 37% yield) as a white solid. ms m/z 109.9 [M + H]+.

[1] Patent: US9617268, 2017, B2. Location in patent: Page/Page column 386; 387
[2] Patent: WO2006/102194, 2006, A1. Location in patent: Page/Page column 25
[3] Patent: WO2006/107784, 2006, A1. Location in patent: Page/Page column 33
[4] Chemische Berichte, 1948, vol. 81, p. 1,10
[5] Journal of the Chemical Society, 1947, p. 239,242