in the apparatus operating in the recycle mode to achieve total
homogeneity between 10 and 20 consecutive cycles employing a
Symmetry C18column (Waters; 7μm, 19300 mm), isocratic elution
with methanol, and a flow rate of 8 mL/min. These techniques afforded
pure compound1(13 mg) from peak I and2(9 mg) from peak II. The
same elution system with a flow rate of 9 mL/min allowed the
purification of3(20 mg) from peak III