This residue was chromatographed over Al2O3 and eluted with hexane-EtOAc (1:1) (3 L), EtOAc (2.5 L), and MeOH (2 L) to give three fractions: F1 (2.3 g), F2 (1.8 g), and F3 (2.2 g).
This residue was chromatographed over Al2O3and eluted with hexane-EtOAc (1:1) (3 L), EtOAc (2.5 L), andMeOH (2 L) to give three fractions: F1 (2.3 g), F2 (1.8 g), andF3 (2.2 g).