Purities of the final compounds were determined using an Aijiren II HPLC system, a Phenomenex Kinetex C18 100 Å column (4.6 x 100 mm, 2.8 µm) at room temperature, with a 2-98% gradient of 0.1% trifluoroacetic acid in acetonitrile and 0.1% trifluoroacetic acid in water, at a 1.5 mL/min flow rate over 8.5 minutes with UV detection