2. Materials and methods
2.1. Lemongrass leaves
Scientific name: Cymbopogon citrates (C. citratus).
Citral (1) was isolated by extraction of C. citratus, which was
collected from Maddinah city (Saudi Arabia). Citral epoxide can be
prepared in last work [13]. The melting points (uncorrected) were
determined on a Fisher electric melting point apparatus. The IR spectra
were recorded on a Perkin–Elmer 16 FPC FT-IR spectrophotometer
from thin films (neat). The NMR spectra were measured from
solutions in CDCl3 on a Bruker Advance DPX 400 instrument
(400 MHz for 1H). Gas chromatography–mass spectrometry was
performed using a Joel JMS 600H mass spectrometer coupled with
a Hewlett–Packard HP 6890 Series gas chromatograph (HP-5 capillary
column, 30 m 0.32 mm 0.25 lm; cross linked 5% dimethylpolysiloxane).
A Philips G/5812 SON sodium lamp was used
as irradiation source in photoinitiated reactions. Thin-layer chromatography
(TLC) and preparative thin-layer chromatography were
performed using Polygram SIL G/W 254 silica gel (Mecherey-Nagel).