6-Amino-3-chloropyridazine → N-(6-chloropyridazin-3-yl)-2-(3-(trifluoromethoxy)phenyl)acetamide

Participants

Reaction Steps

3-Amino-6-chloropyridazine (55.5 g, 0.428 mol) and 3-(Trifluoromethoxy)phenylacetic acid (1.1 equiv., 0.471 mol, 104 g) were dissolved in DMF (30.0 vol., 1.66 L) in a 3000 mL three neck round-bottom flask. Addition of DIEA (1.1 equiv., 0.471 mol, 82 mL) via addition funnel was done over 5 minutes. Propylphosphonic anhydride solution (300 mL of a 50% solution in DMF, 1.1 equiv., 0.471 mol,) was charged into a 500 mL addition funnel and added dropwise to reaction solution (keeping reaction temperature≦+30° C.). The reaction usually goes to completion after 3 hours (TLC: 6:4 hexanes-ethyl acetate). Reaction mixture was then poured into 7.5% sodium bicarbonate (80.0 vol., 4.4 L) which was chilled in an ice bath. Off-white crystalline powder was filtered through a Büchner funnel, rinsed with water (20.0 vol., 1.1 L). Dried in a 50° C. vacuum to a constant weight to afford N-(6-chloropyridazin-3-yl)-2-(3-(trifluoromethoxy)phenyl)acetamide 1117: yield of 119.6 g (77%). 1H NMR (300 MHz, DMSO-d6) δ 11.63 (s, 1H), 8.38 (d, J=9.4 Hz, 1H), 7.88 (d, J=9.4 Hz, 1H), 7.52-7.27 (m, 4H), 3.90 (s, 2H).

Provenance & Evidence