Chemicals were purchased
from Aldrich. Solvents
for extraction and chromatography were of technical grade. All solvents
used in the reactions were dried using an SPS-system. All other reagents
were recrystallized or distilled when necessary. Analytical TLC was
performed with Merck silica gel 60 F254 plates and visualization was
accomplished by UV light. Flash chromatography was carried out using
Merck silica gel 60 (230–400 mesh ASTM). Components were visualized
by staining with a solution of KMnO4. NMR spectra were
obtained using a Varian Unity Plus Varian-400 and a Varian Unity Plus
Varian-500, operating at 399.93 and 499.86 MHz, respectively, for
the 1H nucleus or at 100.57 and 125.70 MHz, respectively,
for the 13C nucleus. Chemical shifts are reported in δ
= units (ppm) relative to the residual protonated solvent signals
of CDCl3 (1H NMR: δ = 7.26 ppm) or at
the carbon absorption in CDCl3 (13C NMR: δ
= 77.0 ppm). Data are reported as follows: chemical shifts, multiplicity
(s = singlet, d = doublet, t = triplet, q = quartet, br = broad, m
= multiplet), coupling constants (Hz), and integration. MS (EI) spectra
were obtained with a Jeol JMS-600 spectrometer. A detailed description
of the synthetic procedures and characterization is included in theSupporting Information .
from Aldrich. Solvents
for extraction and chromatography were of technical grade. All solvents
used in the reactions were dried using an SPS-system. All other reagents
were recrystallized or distilled when necessary. Analytical TLC was
performed with Merck silica gel 60 F254 plates and visualization was
accomplished by UV light. Flash chromatography was carried out using
Merck silica gel 60 (230–400 mesh ASTM). Components were visualized
by staining with a solution of KMnO4. NMR spectra were
obtained using a Varian Unity Plus Varian-400 and a Varian Unity Plus
Varian-500, operating at 399.93 and 499.86 MHz, respectively, for
the 1H nucleus or at 100.57 and 125.70 MHz, respectively,
for the 13C nucleus. Chemical shifts are reported in δ
= units (ppm) relative to the residual protonated solvent signals
of CDCl3 (1H NMR: δ = 7.26 ppm) or at
the carbon absorption in CDCl3 (13C NMR: δ
= 77.0 ppm). Data are reported as follows: chemical shifts, multiplicity
(s = singlet, d = doublet, t = triplet, q = quartet, br = broad, m
= multiplet), coupling constants (Hz), and integration. MS (EI) spectra
were obtained with a Jeol JMS-600 spectrometer. A detailed description
of the synthetic procedures and characterization is included in the