N-Hydroxyphthalimide → HCID 68536180, compound

Participants

Reaction Conditions

Reaction Steps

Triphenylphosphine (21.2 g, 80.7 mmol) and N-hydroxyphthalimide (13.2 g, 80.7 mmol) were added to a solution of 4-(2-butyl-1H-imidazo[4,5-c]quinolin-1-yl)butan-1-ol (16.0 g, 53.8 mmol) in tetrahydrofuran (200 mL). The mixture was stirred for five minutes and then was cooled to approximately 0° C. Diisopropyl azodicarboxylate (19.6 g, 96.8 mmol) was added dropwise, and the reaction was allowed to warm to room temperature and stirred for three hours. An analysis by LC/MS indicated the presence of starting material, and the reaction was stirred at 60° C. overnight. An analysis by LC/MS indicated the presence of starting material, and additional triphenylphosphine, N-hydroxyphthalimide, and diisopropyl azodicarboxylate (26.9 mmol of each) were added to the reaction mixture. The reaction was stirred at room temperature for two hours and heated at reflux for three hours. The reaction was concentrated under reduced pressure, and the residue was dissolved in chloroform (200 mL). The resulting solution was washed with brine (3×150 mL), dried over magnesium sulfate, filtered through a layer of CELITE filter aid, and concentrated under reduced pressure. An analysis of the crude product mixture by LC/MS indicated that starting material was still present. The mixture was dissolved in tetrahydrofuran (200 mL) and treated with triphenylphosphine (21.2 g, 80.7 mmol), N-hydroxyphthalimide (13.2 g, 80.7 mmol), and diisopropyl azodicarboxylate (19.6 g, 96.8 mmol) as described above. The reaction was stirred overnight at room temperature. The product was present as a white precipitate, which was isolated by filtration and washed with tetrahydrofuran to provide 8.68 g of 2-[4-(2-butyl-1H-imidazo[4,5-c]quinolin-1-yl)butoxy]-1H-isoindole-1,3(2H)-dione as a white solid.

Provenance & Evidence