3. Experimental
3.1. General experiment procedures
Melting point was determined using a BU¨ CHI Melting Point M-560 apparatus and is uncorrected. IR Spectrum was recorded on Bruker Vector 22 spectrophotometer. Optical rotation was measured on JASCO P-2000 polarimeter. EIMS was recorded on
JEOL JMS-6OO H and HREIMS was measured on Thermo Finnigan MAT 95 XP.
The 1D 2D NMR spectra were recorded on Bruker Avance AV spectrometer, operating at 600 MHz for 1H NMR and 150 MHz for 13C NMR by using residual solvent signal as internal reference. The chemical shifts are reported in d (ppm) and the coupling constants (J) are given in Hz. VLC was performed by using silica gel 60 GF254 (Merck). Silica gel 9385 (Merck) and Sephadex LH-20 (Sigma–Aldrich) were used for column chromatography. All
the solvents were distilled commercial grade. Petrol used was of the boiling range (60–80 8C). TLC was performed on silica gel (60 F254), coated on aluminum sheets (Merck, 20 cm 20 cm, 0.2 mm thickness) and visualized under UV light at 254 and 360 nm and by
spraying with 5% H2SO4 solution in MeOH, followed by heating.