Reactions of Bifunctional Sulfur Compounds with Dihydrazido Phosphoric Acid Derivatives—Five- and Six-Membered Rings with Four N-Atoms

Thionylchloride and sulfurdichloride react with N-substituted phosphoric acid or thiophosphoric acid dihydrazides in the presence of triethylamine to yield six-membered rings containing sulfur if the substituents at N adjacent to the sulfur are electron-withdrawing groups such as -C(=O)Et. These groups lacking redox reactions are observed, resulting in the formation of a five-membered ring with an NN double bond that contains no sulfur. The X-ray structure of this “λ5-phosphatetrazolin” has been investigated: the ring is planar, PN 1.665(6), 1.680(6), N-N 1.372(9), 1.385(10), N=N 1.275(10)Å.