Hydrochloric Acid → HCID 57717588, compound

Participants

Reaction Steps

Acetyl chloride (221 μL, 3.14 mmol) was added to a 0° C. stirred solution of 1-(2-amino-2-methylpropyl)-2-propyl-2H-pyrazolo[3,4-c]quinolin-4-amine (prepared as described in Example 64, 840 mg, 2.82 mmol) and triethylamine (591 μL, 4.24 mmol) in dichloromethane (25.2 mL). The solution was stirred for 20.5 h at ambient temperature, then was concentrated under reduced pressure to yield a foam that was dissolved in methanol. To the solution was added concentrated hydrochloric acid (2 mL). The solution was stirred at ambient temperature for 90 minutes, then heated at reflux for 40 minutes. After cooling to ambient temperature, the solution was concentrated under reduced pressure and 2 M aqueous sodium carbonate was added until the pH was basic. The solution was extracted with chloroform. The organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was dissolved in dichloromethane (10 mL), then triethylamine (786 mL) and acetyl chloride (300 mL) were added. The reaction was worked up as before, then methanol (20 mL) and concentrated hydrochloric acid (2 mL) were added. The solution was heated at reflux for 30 minutes, left to stand at ambient temperature overnight, then heated at reflux again for 30 minutes. After cooling to ambient temperature, the solution was concentrated under reduced pressure and 2M aqueous sodium carbonate was added until the pH was adjusted to pH 10-11. The solution was extracted with chloroform three times. The organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified twice by chromatography on a HORIZON HPFC system (silica gel, gradient elution with 20-30% CMA in chloroform for the first column; gradient elution with 4-10% methanol in chloroform for the second column). The appropriate fractions were combined and concentrated under reduced pressure to yield a colorless foam that was crystallized from ethyl acetate/hexanes. A white solid was isolated and dried under vacuum at elevated temperature to yield 698 mg of N-[2-(4-amino-2-propyl-2H-pyrazolo[3,4-c]quinolin-1-yl)-1,1-dimethylethyl]acetamide as a white solid, mp 182-183° C.

Provenance & Evidence