Dimethyl Sulfoxide → di(tert-butyl) 1-(4-oxobutyl)-2-propyl-2H-pyrazolo[3,4-c]quinolin-4-ylimidodicarbonate

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Reaction Steps

To dichloromethane (5 mL) at −78° C. was added dimethylsulfoxide (0.12 mL, 1.6 mmol) and oxalyl chloride (0.11 mL, 1.2 mmol). After several minutes, a solution di(tert-butyl) 1-(4-hydroxybutyl)-2-propyl-2H-pyrazolo[3,4-c]quinolin-4-ylimidodicarbonate (0.5449 g, 1.093 mmol) and triethylamine (0.46 mL, 3.3 mmol) in dichloromethane (5 mL) was added dropwise to the −78° C. solution. After 15 minutes, the cooling bath was removed and the solution was allowed to warm to ambient temperature, during which time more dichloromethane (20 mL) was added. The solution was transferred to a separatory funnel and washed with aqueous potassium carbonate, water, and brine. The solution was dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting oil was dried under vacuum to yield 0.5845 g of di(tert-butyl) 1-(4-oxobutyl)-2-propyl-2H-pyrazolo[3,4-c]quinolin-4-ylimidodicarbonate that contained a small amount of dimethylsulfoxide, but was used without further purification.

Provenance & Evidence