All the chemicals were purchased from Merck, Fluka and
Sigma-Aldrich. The reactions were monitored by thin layer
chromatography (TLC). The products were isolated and identified
by comparing their physical and spectral data with authentic
samples. Infrared (IR) spectra were recorded on FT-IR
JASCO-680, 1H-NMR spectra were obtained on a Bruker
DPX-300 MHz and melting points were determined on a
Barnstead Electrothermal (BI 9300) apparatus.