in toluene anhydrous conditions, -78°C, stirred and warmed to 25°C, stirred for 2 days; filtered, filtrate vac.-evapd., distn. at 45°C/20Torr; byproducts not isolated, detected by GC/mass spectroscopy; elem. anal.;

in toluene anhydrous conditions, reflux for 48 h;

anhydrous conditions;