2,2,2-Trifluoroethanol → 6-(2-Chlorophenyl)-7-(4-chlorophenyl)-3-(2,2,2-trifluoroethoxy)-[1,2,4]triazolo[4,3-b]pyridazine

Participants

Reaction Steps

A mixture 3-chloro-6-(2-chlorophenyl)-7-(4-chlorophenyl)-[1,2,4]triazolo[4,3-b]pyridazine (38 mg, 0.1 mmol), 2,2,2-trifluoroethanol (22 μL, 0.2 mmol), 2-tert-butylimino-2-diethylamino-1,3-dimethyl-perhydro-1,3,2-diazaphosphorine (60 μL, 0.3 mmol) and anhydrous THF (0.5 mL) in a sealed tube was stirred at 70° C. for 3 days. After cooling to room temperature, the reaction mixture was concentrated under reduced pressure. The obtained residue was purified using reverse phase preparative HPLC (Conditions: Phenomenex Luna 5μ C18 21.2×100 mm; Eluted with 60% to 100% B, 10 min gradient, 100% B hold for 5 min, (A=90% H2O, 10% MeOH and B=10% H2O, 90% MeOH); Flow rate at 20 mL/min, UV detection at 220 nm) to yield 30 mg of the desired product with 90% purity. The impure product was further purified using a silica gel cartridge (4 g) eluting with a gradient of EtOAc (30-100%) in hexanes to afford 24 mg (55%) of the title compound as a white solid. HPLC/MS (method A): retention time=3.81 min, (M+H)+=439.1. 1H NMR (CDCl3, 400 MHz): δ 7.92 (s, 1H), 7.40-7.49 (m, 1H), 7.29-7.33 (m, 2H), 7.14-7.30 (m, 3H), 7.09 (d, J=8.56 Hz, 2H), 5.05-5.07 (m, 2H).

Provenance & Evidence