4.1.1. General considerations
1
H NMR spectra were recorded on an instrument operating at
400 MHz and 13
C NMR spectra at 100 MHz and DMSO-d6 used as
solvent unless otherwise stated. The chemical shifts are given in
ppm relative to internal tetramethylsilane (TMS) and coupling
constants (J) in Hz. IR were recorded on a Bruker FT-IR Tensor 27.
Samples were measured as KBr disks, and themain bands are given
in cm1
. Mass spectra were recorded under electrospray ionization
(ESI) and HRMS spectra were obtained in the University of Vigo or
at Raidt e University of Santiago de Compostela. Melting points
were measured on an EZ-Melt automated melting point apparatus
and are uncorrected. Flash chromatography was performed with
Fluka silica gel Kieselfel G.