Trifluoroacetic acid → 6-(6-Methyl-[1,2,4]triazolo[4,3-b]pyridazin-3-ylsulfanyl)-3-(1h-pyrazol-4-yl)-quinoline

Participants

Reaction Steps

A microwave vessel was charged with 3-bromo-6-(6-methyl-[1,2,4]triazolo[4,3-b]pyridazin-3-ylsulfanyl)-quinoline (970 mg, 2.606 mmol), 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-pyrazole (930 mg, 2.866 mmol), and dichlorobis(triphenylphosphine) palladium(0) (92 mg, 0.13 mmol). 1,4-Dioxane (10 mL) and a 2 M aqueous solution of sodium carbonate (5 mL) were added. The vessel was capped and microwaved at 130° C. for 30 min. The reaction mixture was partitioned between water and 10% methanol/dichloromethane. The aqueous layer was extracted with 10% methanol/dichloromethane, and the combined organics were adsorbed on silica gel. Purification by flash chromatography on silica gel using a gradient of 0-8% methanol/dichloromethane afforded 1.073 g of the crude coupling product as a light brown oil. The oil was treated with TFA (10 mL). The reaction mixture was stirred at room temperature for 2 h, before concentrating in vacuo. The residue was treated with 1 N aqueous NaOH, and the precipitate was filtered, washed sequentially with water and ethyl acetate. The resulting yellow solid was dissolved in 10% methanol/dichloromethane and adsorbed on silica gel. Purification by flash chromatography on silica gel using a gradient of 0-10% methanol/dichloromethane afforded 417 mg of impure 6-(6-methyl-[1,2,4]triazolo[4,3-b]pyridazin-3-ylsulfanyl)-3-(1H-pyrazol-4-yl)-quinoline. Purification of 30 mg of material by mass-triggered HPLC (5-95% CH3CN/H2O, 0.1% HCOOH modifier) provided 12 mg of pure 6-(6-methyl-[1,2,4]triazolo[4,3-b]pyridazin-3-ylsulfanyl)-3-(1H-pyrazol-4-yl)-quinoline.

Provenance & Evidence