P‐N Compounds. 27 . Synthesis of a 5‐amino‐4,6‐dioxo‐1,3,5,2‐triazaphosphorine 2‐oxide

Heating N 4 ‐phenylphosphinyl‐bis‐( N 1 ‐dimethyl) semicarbazide in the presence, but not in the absence, of iodomethane gave 2‐phenyl‐5‐dimethylamino‐4,6‐dioxo‐1,3,5,2‐triazaphosphorine 2‐oxide and a mechanism for this reaction is proposed. The compound was also prepared by the addition of 1,1‐dimethylhydrazine to phenylphosphonic diisocyanate. Treatment of the product with excess iodomethane gave a polymeric material and 1,1,1‐trimethylhydrazinium iodides.