Trifluoroacetic acid → N-(6-(4-(5-amino-1,3,4-thiadiazol-2-yl)butyl)pyridazin-3-yl)-2-(3-(trifluoromethoxy)phenyl)acetamide

Participants

Reaction Conditions

Reaction Steps

1118 (1.0 equiv., 0.154 mol, 58.2 g) was charged into a 500 mL round bottom flask along with thiosemicarbazide (1.2 equiv., 0.184 mol, 16.8 g). TFA (5 vol., 291 mL) slowly added to reaction vessel while stirring. The reaction slurry was heated in a 65° C. bath with an open top reflux condenser. The reaction usually goes to completion after 5 hours (determined by LC/MS). Toluene (10 vol., 582 mL) added to deep red solution, azeotroped by rotary evaporation (bath≦30° C.) to a red oil. Slowly transferred oil to a well stirred 6000 mL Erlenmeyer flask containing 7.5% sodium bicarbonate solution (69 vol., 4.0 L) cooled in a 0° C. bath. The crystals were filtered through a Büchner funnel and rinsed twice with diethyl ether (5 vol., 2×250 mL). Dried under high vacuum to a constant weight to afford N-(6-(4-(5-amino-1,3,4-thiadiazol-2-yl)butyl)pyridazin-3-yl)-2-(3-(trifluoromethoxy)phenyl)acetamide 657; yield of 55.7 g (80%). 1H NMR (300 MHz, DMSO-d6) δ 11.33 (s, 1H), 8.21 (d, J=9.2 Hz, 1H), 7.58 (d, J=9.2 Hz, 1H), 7.51-7.26 (m, 4H), 6.99 (s, 2H), 3.88 (s, 2H), 2.87 (m, 4H), 1.71 (m, 4H).

Provenance & Evidence