A new synthetic route to cyclophosphadithiatriazenes: synthesis and X‐ray structural characterization of the first spirocycle containing thiadiazaphosphetidine and phosphadithiatriazene heterocycles

The phosphetidine 2,4‐Di‐ tert ‐butyl‐3‐chloro‐1λ 6 ‐thia‐2,4‐diaza‐3‐phosphetidine‐1,1‐dioxide, O 2 S ( t BuN) 2 PCl, reacts with tetrasulfur tetranitride, S 4 N 4 , in benzene under reflux to afford the novel 4,6‐spirocycle in moderate yield. The deep‐blue crystals of the spirocycle are airstable and high melting in nature. The spiro phosphorus atom subtends a four‐membered P V S VI N 2 ring which is saturated, and a six‐membered P V S $^{\rm IV}_{2}$ N 3 ring which is unsaturated. The single‐crystal X‐ray structure of this first example of the spirocycle reveals a planar PSN 2 ring and a puckered PS 2 N 3 ring and the molecule is symmetric in nature. Copyright © 2006 John Wiley & Sons, Ltd.