Thin layer chromatography was carried out on aluminum plates, precoated with silica gel, Merck Si60 F254. Preparative column chromatography was performed on glass columns packed with silica gel (particle size 40-63 m) from Macherey-Nagel or aluminum oxide, Merck 90 active basic, particle size 63-200 m. HPLC were conducted on a Shimadzu CBM-20A equipped with a SPD-20A UV-vis detector, a LC-8A-solvent facility, and a column Nucleosil 100-5 NO2 from Macherey-Nagel.