Propylamine → Pro-Thr(OBn) n-propylamide Hydrochloride

Participants

Reaction Conditions

Reaction Steps

Commercially available Boc-L-Thr(OBn)-OH (5 g) was mixed with 1-hydroxybenzotriazole (2.62 g), diisopropylethylamine (2.08 g) in methylene chloride (14 mL) and cooled to 0° C. To this was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, followed by n-propylamine (1.14 g) 2 minutes later. After allowing the reaction mixture to stir at 0 for 5 hours, the organic solution was washed sequentially with water, 1N hydrochloric acid, 5% sodium bicarbonate, then dried (magnesium sulfate), filtered and evaporated to obtain an oily residue. This residue was taken up in 4M hydrogen chloride in dioxane solution (50 mL) and allowed to stand at room temperature for 30 minutes. The solvent was then evaporated and the product triturated with ether. The resulting solid was collected a filter plate. A portion of this material (1.5 g) was then mixed with Boc-L-Pro-OSu (1.5 g) in methylene chloride (20 mL), cooled to 0° C., and diisopropylethylamine (675 mg) was added. After allowing the reaction mixture to stir at 0° C. for 5 hours, the organic solution was washed sequentially with water, 1N hydrochloric acid, 5% sodium bicarbonate, then dried (magnesium sulfate), filtered and evaporated to obtain an oily residue. This residue was taken up in 4 M hydrogen chloride in dioxane solution (50 mL) and allowed to stand at room temperature for 30 minutes. The solvent was then evaporated and the product triturated with ether. The resulting solid was collected a filter plate to yield the title compound (1.45 g). 1H NMR (400 MHz): consistent with proposed structure.

Provenance & Evidence