Diphenylketene with Nitrogen Trichloride

Diphenylketene reacts with nitrogen trichloride in carbon tetrachloride solution. When this solution is warmed to 50° C with sodium hydroxide the addition product undergoes a rearrangement with the formation of imidobenzophenone. This rearrangement is similar to the rearrangement in Hofmann\u27s method for the preparation of primary amines from amides. On passing dry HCl into the carbon tetrachloride solution, the hydrochloride of this compound is precipitated