3-Pyridine aldoxime → di(tert-butyl) 2-propyl-1-[3-(3-pyridin-3-ylisoxazol-5-yl)propyl]-6,7,8,9-tetrahydro-2H-pyrazolo[3,4-c]quinolin-4-ylimidodicarbonate

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Reaction Steps

Under a nitrogen atmosphere, N-chlorosuccinimide (2.1 g, 16 mmol) was added to a solution of 3-pyridine aldoxime (2.0 g, 16 mmol) in THF (10 mL). The solution was stirred at ambient temperature for 4 hours. A solution of di(tert-butyl) 1-pent-4-ynyl-2-propyl-6,7,8,9-tetrahydro-2H-pyrazolo[3,4-c]quinolin-4-ylimidodicarbonate (4.00 g, 8.05 mmol), prepared as described in Example 615, and anhydrous triethylamine (2.5 mL, 18 mmol) in THF (10 mL) was added and the reaction solution was heated at 60° C. for 18 hours. The reaction solution was concentrated under reduced pressure to provide a black oil. The oil was dissolved in dichloromethane, washed sequentially with potassium carbonate, water, and brine, dried over sodium sulfate, and filtered. The filtrate was purified by column chromatography (silica gel, elution with a gradient of 20-80% ethyl acetate in hexanes) to provide 1.0877 g of di(tert-butyl) 2-propyl-1-[3-(3-pyridin-3-ylisoxazol-5-yl)propyl]-6,7,8,9-tetrahydro-2H-pyrazolo[3,4-c]quinolin-4-ylimidodicarbonate.

Provenance & Evidence