In the preparation of NMR studies, a 90 mg sample
of OLR was dissolved in 0.5 mL of deuterated dimethyl sulfoxide (DMSO-d6). The 2D HSQC NMR spectra were recorded on
an Agilent ProPulse 500 MHz spectrometer (Agilent Tech., Santa Clara,
USA) and recorded in the gradient HSQC adiabatic mode. The spectral
widths were 20 000 and 5000 Hz for the 13C and 1H dimensions, respectively. A total of 1024 complex points
were collected for the 1H dimension, with a recycle delay
of 1.5 s and 128 transients, whereas 256 time increments were recorded
in the 13C dimension. Before Fourier transformation, the
data matrices were zero-filled to 1024 points in the 13C dimension.
of OLR was dissolved in 0.5 mL of deuterated dimethyl sulfoxide (DMSO-d6). The 2D HSQC NMR spectra were recorded on
an Agilent ProPulse 500 MHz spectrometer (Agilent Tech., Santa Clara,
USA) and recorded in the gradient HSQC adiabatic mode. The spectral
widths were 20 000 and 5000 Hz for the 13C and 1H dimensions, respectively. A total of 1024 complex points
were collected for the 1H dimension, with a recycle delay
of 1.5 s and 128 transients, whereas 256 time increments were recorded
in the 13C dimension. Before Fourier transformation, the
data matrices were zero-filled to 1024 points in the 13C dimension.