(Acylation Method A) p-Toluoyl chloride (0.22 mL, 1.6 mmol) was added via syringe to a 15° C. stirring mixture of (R)-2-(4-methoxybenzoylamino)-2-phenylethylamine (0.40 g, 1.48 mmol), potassium carbonate (0.27 g, 1.9 mmol), 1,4-dioxane (8 mL), and water (4 mL). TLC analysis (80% methylene chloride, 18% methanol, 2% ammonium hydroxide) indicated reaction completion within 1 h. The solution was diluted with water, and the precipitated solid was collected by vacuum filtration. The precipitate was recrystallized from methanol and dried under vacuum at 50° C. overnight to afford the title compound (0.42 g, 72%) as a white solid.
