Diisopropylethylamine → HCID 13391124, compound

Participants

Reaction Steps

To a suspension of Boc-D-phenylalanine (42.4 g, 160 mmol) in methylene chloride was added proline benzyl ester hydrochloride (38.7 g, 160 mmol), 1-hydroxybenzotriazole hydrate (21.6 g, 160 mmol) and diisopropylethylamine (83 mL, 480 mmol). Once the solution was homogeneous, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (40 g, 200 mmol) was added. This mixture was allowed to stir at room temperature for 16 hrs and was then concentrated in vacuo. The residue was dissolved in ethyl acetate (500 mL) and this solution was washed twice with saturated aqueous ammonium chloride (400 mL), twice with saturated aqueous bicarbonate (400 mL), and twice with brine (400 mL). The organic solution was dried (MgSO4), filtered and concentrated in vacuo to give 74.6 g (103%) of a straw colored syrup. This syrup was dissolved in p-dioxane (400 mL) and anhydrous HCl gas was bubbled through for 15 minutes and was allowed to stir for 3 hr at room temperature. The solution was concentrated in vacuo to give a yellow foam coating the sides of the flask. The foam was washed several times with diethyl ether and the solvent was decanted. The foam was dried under high vacuum to give 61 g (98%).

Provenance & Evidence