2.4. X-ray crystal structure analysis of compounds 1 and 4
Colorless crystals of 1 and 4were obtained fromMeOH. The intensity
data were collected on an Xcalibur Onyx Nova diffractometer with CuKα radiation. The crystal structures of 1 and 4 were solved by the direct
method (SHLXS-97), expanded using difference Fourier technique,
and refined by the program and the full-matrix least-squares calculations.