Phosgene → Sulphonyl diisocyanate

Participants

Reaction Steps

The sulfonamide of Example 5 (5.0 g) was stirred in 75 mL dry xylenes with 0.1 g DABCO® and 1.9 mL n-butylisocyanate, then heated to reflux (138°) with a dry ice condenser in place. Phosgene gas was introduced into the vessel above the liquid level until the reaction temperature dropped below 130°. As phosgene was absorbed by the reactants, a gradual rise in reaction temperature was observed. Heating was continued until the reaction temperature remained constant, indicating complete consumption of the sulfonamide starting material (ca. 2 hrs). Evaporation of the xylenes after filtration under nitrogen to remove traces of solid gave crude sulfonyl isocyanate as a viscous oil, IR (neat) 2250 cm-1.

Provenance & Evidence