Dichlorodiazirine: a nitrogenous precursor for dichlorocarbene

The reaction of 3-p-nitrophenoxy-3-chlorodiazirine with a 1.1:1.0:1.6 blend of tetrabutylammonium chloride, cesium chloride, and the ionic liquid 1-butyl-3-methylimidazolium chloride at 40-50 degrees C under vacuum at 1 mm.Hg produced a melt from which dichlorodiazirine distilled into a cold trap containing pentane at -70 degrees C over 6-7 h. Dichlorodiazirine, the first nitrogenous precursor for dichlorocarbene, was reasonably stable in the dark at 25 degrees C and efficiently generated the carbene upon photolysis.