Ethylene Glycol → Dibenzyl-(4-[1,3]dioxolan-2-yl-2,5-dimethyl-phenyl)amine

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Reaction Steps

To a 500 mL round-bottomed flask was added 4-dibenzylamino-2,5-dimethylbenzaldehyde hydrochloride (11.5 g, 31.4 mmol) and toluene (150 mL) and the resulting mixture was stirred until the salt completely dissolved. The reaction flask was then purged with dry nitrogen for 5 minutes. Ethylene glycol (5.25 mL, 94.2 mmol) and p-toluenesulfonic acid (760 mg, 6.2 mmol) were added and the resulting mixture was heated at 60° C. to 80° C. for about 20 hours. The solvent was then removed slowly (over about 40 minutes) at 40° C. on a rotary evaporator. Toluene (100 mL) was added to the residue and the solvent was again removed slowly at 40° C. on a rotary evaporator. This process was repeated using another aliquot of toluene (100 mL) and the mixture was evaporated to dryness. Ethyl acetate (150 mL) and saturated aqueous sodium bicarbonate (100 mL) were added to the residue and the layers were separated. The organic layer was washed with brine (50 mL) and then dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to provide crude dibenzyl-(4-[1,3]dioxolan-2-yl-2,5-dimethyl-phenyl)amine (11.4 g).

Provenance & Evidence