Melting points were determined on a Gallenkamp
instrument and are uncorrected. FTIR spectra were recorded
on a Bomem Hartmann and Braun, MB-Series
instrument; UV spectra were recorded on a Hitachi U-
2000 spectrophotometer. EI and ESI MS spectra were
obtained from a Finnigan LC-Q Classic, Ion Trap
Spectrometer and a Hewlett–Packard Mass Spectrometer
(Model No. 5989A). 1H and 13C NMR spectra were
acquired using Bruker Avance 300 and 400 MHz spectrometers
equipped with 5 mm bore gradient-pulse inverse
probeheads. Samples were dissolved in DMSO-d6
and chemical shifts were recorded in d (ppm) relative to
that of TMS (d ¼ 0:00 ppm).