Phosphorus pentachloride → 4-(3-bromo-4-fluorophenyl)-3-(4-{[4-(morpholin-4-ylmethyl)benzyl]amino}-1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazol-5(4H)-one

Participants

Reaction Steps

A solution of N-{4-[4-(3-bromo-4-fluorophenyl)-5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl]-1,2,5-oxadiazol-3-yl}-4-(morpholin-4-ylmethyl)benzamide trifluoroacetate (60 mg, 91 μmol) in benzene (1.8 mL) was treated with phosphorus pentachloride (76 mg, 0.36 mmol) and stirred at reflux for 2.5 h. The reaction mixture was concentrated to a residue which was diluted with ethanol (1.4 mL), treated with sodium cyanoborohydride (17 mg, 0.27 mmol), and stirred for 2 h. The reaction mixture was quenched with acetic acid (50 μL) and purified by preparative LCMS to give the intermediate, 4-(3-bromo-4-fluorophenyl)-3-(4-{[4-(morpholin-4-ylmethyl)benzyl]amino}-1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazol-5(4H)-one. This material was diluted with ethanol (1 mL), treated with 2.0 M sodium hydroxide in water (0.2 mL, 4 mmol), and stirred for 45 min. The reaction mixture was purified by preparative LCMS to give the desired product (15 mg, 27%). LCMS for C21H23BrFN6O3 (M+H)+: m/z=505.0, 507.0.

Provenance & Evidence