The chemical structures of compounds were determined by spectroscopic methods,1H and13C-nuclear magnetic resonance spectroscopy (NMR) and gas chromatography–mass spectrometry (GC–MS).1H and13C NMR spectra were recorded on a Bruker Avance DPX-500MHz spec- trometer, with deuterochloroform (CDCl3) and tetramethylsilane (TMS) as internal standards for the chemical shift parameter (ı) (13C 77.0mgkg−1, residual1H 7.24mgkg−1).