EXPERIMENTAL SECTION
General Experimental Procedures. Optical rotations were
measured on a Perkin-Elmer model 241 polarimeter. IR spectra
were run on a JASCO FT/IR-410 spectrometer, equipped with a
Specac Silver Gate ATR system by applying a film on a germanium
plate. 1D- and 2D-NMR spectra were recorded on a Bruker DRX-500
MHz NMR spectrometer. Chemical shifts (δ) are expressed in ppm
with reference to the solvent signals (CDCl3; 1H: 7.24 ppm; 13C:
77.00 ppm), and coupling constants (J) are reported in Hz. All NMR
experiments were obtained by using standard pulse sequences supplied
by the vendor. HRTOFMS and MS/MS spectra were recorded on a
Micromass QTOF-2 spectrometer. EIMS and HREIMS spectra were
recorded on a Finnigan MAT 95 spectrometer. Column chromatography
was carried out on silica gel (200−400 mesh, Natland
International Corporation). Reversed-phase flash chromatography
was accomplished with RP-18 silica gel (40−63 μm, EM Science),
and reversed-phase HPLC was carried out on a Waters 600E Delivery
System pump, equipped with a Waters 996 photodiode detector and a
GROM-Saphir 110 C18 column (120 Å, 12 μm, 300 × 40 mm), or a
Phenomenex, LUNA-C18 column (12 μm, 250 × 50 mm). Thin-layer
chromatography was performed on Whatman glass-backed plates
coated with 0.25 mm layers of silica gel 60.
EXPERIMENTAL SECTION
General Experimental Procedures. Optical rotations were
measured on a Perkin-Elmer model 241 polarimeter. IR spectra
were run on a JASCO FT/IR-410 spectrometer, equipped with a
Specac Silver Gate ATR system by applying a film on a germanium
plate. 1D- and 2D-NMR spectra were recorded on a Bruker DRX-500
MHz NMR spectrometer. Chemical shifts (δ) are expressed in ppm
with reference to the solvent signals (CDCl3; 1H: 7.24 ppm; 13C:
77.00 ppm), and coupling constants (J) are reported in Hz. All NMR
experiments were obtained by using standard pulse sequences supplied
by the vendor. HRTOFMS and MS/MS spectra were recorded on a
Micromass QTOF-2 spectrometer. EIMS and HREIMS spectra were
recorded on a Finnigan MAT 95 spectrometer. Column chromatography
was carried out on silica gel (200−400 mesh, Natland
International Corporation). Reversed-phase flash chromatography
was accomplished with RP-18 silica gel (40−63 μm, EM Science),
and reversed-phase HPLC was carried out on a Waters 600E Delivery
System pump, equipped with a Waters 996 photodiode detector and a
GROM-Saphir 110 C18 column (120 Å, 12 μm, 300 × 40 mm), or a
Phenomenex, LUNA-C18 column (12 μm, 250 × 50 mm). Thin-layer
chromatography was performed on Whatman glass-backed plates
coated with 0.25 mm layers of silica gel 60.
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