Water → 6-Bromo-7-methyl-8-(3-trifluoromethyl-phenyl)-2H-[1,2,4]triazolo[4,3-a]pyridin-3-one

Participants

Reaction Conditions

Reaction Steps

A solution of 5-bromo-2-chloro-4-methyl-3-(3-trifluoromethyl-phenyl)-pyridine (Int. 14, 176 mg, 0.503 mmol) and hydrazine hydrate (2.5 mL, 52 mmol) in dioxane (5 mL) was heated at 90° C. for 7 hrs. A further quantity of hydrazine hydrate (2.5 mL) was added and the reaction mixture heated at 90° C. for 18 hrs and then at 100° C. for 5 days. The reaction mixture was cooled then poured into water (15 mL) and extracted with EtOAc (3×15 mL). The combined organic extracts were dried (Na2SO4), filtered and evaporated in vacuo to afford a yellow solid. The solid was dissolved in THF (2 mL) and then N,N′-carbonyldiimidazole (375 mg, 2.31 mmol) was added and the reaction mixture stirred at RT for 22 hrs before being concentrated in vacuo. The resultant residue was purified by flash chromatography, eluting with a gradient of 0-100% EtOAc in cyclohexane to give the title compound as a tan solid (184 mg).

Provenance & Evidence