For the NMR analysis, the 1H (300.06 MHz) and 13C NMR (75.45 MHz)
spectra were obtained using a deuterated chloroform (CDCl3) solution
using a Mercury-300BB spectrometer with the d (ppm) value
and the spectra referred to those of CDCl3 (d: 7.27 for 1H and
77.00 for 13C) as an internal standard.