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

Participants

Reaction Conditions

Reaction Steps

N-(6-(4-cyanobutyl)pyridazin-3-yl)-2-phenylacetamide (14.7 g, 50.2 mmol) was charged into a 250 mL round bottom flask fitted with an open top reflux condenser. To the flask was added thiosemicarbazide (5.03 g, 55.2 mmol) and trifluoroacetic acid (88 mL). The reaction slurry was heated in a 65° C. bath for 2 h. After cooling to RT, H2O (150 mL) was added and stirred for 30 minutes. The mixture was then slowly transferred to a stirred 7.5% sodium bicarbonate solution (1400 mL) cooled in a 0° C. bath. The precipitate was collected by suction filtration, rinsed with water (2×200 mL), diethyl ether (2×200 mL) and dried under high vacuum overnight. The off-white solid was slurried in DMSO (200 mL) and heated in an 80° C. bath until the internal temperature reached 65° C. DMSO (105 mL) was used to rinse sides of flask. H2O (120 mL) was slowly added until the solution became slightly cloudy and then the mixture was removed from heat bath and allowed to cool to ambient temperature while stirring. The pale green precipitate was collected by suction filtration, rinsed with water (200 mL) and diethyl ether (2×200 mL). The solid was dried overnight under high vacuum to provide N-(6-(4-(5-amino-1,3,4-thiadiazol-2-yl)butyl)pyridazin-3-yl)-2-phenylacetamide (1024, 15.01 g). 1H NMR (300 MHz, DMSO-d6) δ 11.28 (s, 1H), 8.23 (d, J=8.916 Hz, 1H), 7.59 (d, J=8.826 Hz, 1H), 7.36 (m, 5H), 7.07 (s, 2H), 3.78 (s, 2H), 2.87 (t, J=6.799 Hz, 4H), 1.69 (bm, 4H)

Provenance & Evidence