The reaction mixture was then washed twice with 3.0 mL of
water, and the chloroform fraction was dehydrated over magnesium sulphate, concentrated and analyzed by a gas chromatography
apparatus (PerkinElmer Clarus 600T) equipped with a column elite
5-MS (5% diphenyldimethylpolysiloxane, 30 m length, an outside
diameter of 0.25 mm and an inside diameter of 0.25 m), and with
mass detector carrier gas (He) set to 1.0 mL/min. The temperature
was maintained at 80 ◦C for 2 min, then increased to 250 ◦C with
a rate of 15 ◦C/min and held for 5 min at this temperature; the
injected volume was 1 L with an injector temperature of 250 ◦C