The 2D
1
H NMR and
13
C NMR spectra were recorded with
Brucker AM-500, Switzerland, (500MHz) spectrophotometer with the
solvent signal as internal reference and chemical shifts were given in
ppm. The compound sample was dissolved (7 mg for
H NMR and 3
mg for
13
1
C NMR) in 3 ml of CDCl
3
and analysed by nuclear magnetic
resonance (NMR).