Optical rotations were measured in MeOH using a Perkin-Elmer 341 Polarimeter. 1 H-, 13 C-NMR and 2D-NMR measurements were recorded in CD3OD on a Bruker Avance III 600 spectrometer
( 1 H at 600 MHz and 13 C at 150 MHz) equipped with a 5 mm TCI cryoprobe. 2D-NMR experiments were performed using standard Bruker microprograms (TopSpin 3.5 software). HR-ESI-MS analysis was conducted using a Micromass Q-TOF micro instrument. Flash chromatography was carried out on a Grace Reveleris system equipped with dual UV and ELSD detection using Grace® cartridges (Silica gel or RP-C18). HPLC separations were performed on a Dionex apparatus equipped with an ASI-100 autosampler, an Ultimate 3000 pump, a STH 585 column oven, a diode array detector UVD 340S and a Chromeleon software. A prepacked RP-C18 column (Phenomenex 250 x 10 mm, Luna 5 µ) was used for semi-preparative HPLC. The eluting mobile phase consisted of H2O with TFA (0.0025%) and CH3CN with a flow rate of 5 mL/min and the chromatogram was monitored at 205 and 210 nm. Thin-layer chromatography (TLC) was carried out using silica gel 60 F254 pre-coated aluminium plates (0.2 mm, Merck). After developing with solvent systems, spots were visualized by spraying with 50% H2SO4 followed by heating.
( 1 H at 600 MHz and 13 C at 150 MHz) equipped with a 5 mm TCI cryoprobe. 2D-NMR experiments were performed using standard Bruker microprograms (TopSpin 3.5 software). HR-ESI-MS analysis was conducted using a Micromass Q-TOF micro instrument. Flash chromatography was carried out on a Grace Reveleris system equipped with dual UV and ELSD detection using Grace® cartridges (Silica gel or RP-C18). HPLC separations were performed on a Dionex apparatus equipped with an ASI-100 autosampler, an Ultimate 3000 pump, a STH 585 column oven, a diode array detector UVD 340S and a Chromeleon software. A prepacked RP-C18 column (Phenomenex 250 x 10 mm, Luna 5 µ) was used for semi-preparative HPLC. The eluting mobile phase consisted of H2O with TFA (0.0025%) and CH3CN with a flow rate of 5 mL/min and the chromatogram was monitored at 205 and 210 nm. Thin-layer chromatography (TLC) was carried out using silica gel 60 F254 pre-coated aluminium plates (0.2 mm, Merck). After developing with solvent systems, spots were visualized by spraying with 50% H2SO4 followed by heating.