With phosphorus-nitrogen bonds

A number of ab initio molecular orbital calculations have been performed on acyclic and cyclic phosphazenes. These calculations point to a phosphorus-nitrogen bond with a large degree of charge separation and a small but essential contribution from phosphorus d-orbitals. 

Suitable methods for linking a phosphorus—nitrogen bond to the aziridine ring are the aminolysis of halogenated phosphorus compounds (2,280—282), the transamination of phosphoramines with excess aziridine (283), the reaction with phosphites (284) and phosphoramidites (285) which have a free OH group, or the reaction of phosphines with aziridines and carbon tetrachloride (286). 

A related approach is to synthesize a polyphosphazene with an amino-drug linked directly to phosphorus through a side-group phosphorus-nitrogen bond. The procaine derivative shown in 3.91 is a typical example designed to release the local anesthetic as an adjunct to dental or minor surgical procedures. Derivatives that contain benzocaine,... 

Following the development of schradan (12) in 1941, discussed earlier under pyrophosphoric acid derivatives, it was only after an interval of more than two decades that other insecticides were developed with a phosphorus-nitrogen bond in the molecule. 

Two interesting examples of phosphorus-nitrogen bond cleavage have been reported by Cavell et al. (48), (50b) who found that dimethyla-minodifluorophosphine reacts with difluorophosphoric acid or difluoro-phosphorothioic acid F2P(X)XH (X = 0 or S) to give compounds of empirical formula [F2PX]2, which contain phosphorus in both tervalent and pentavalent oxidation states, e.g. (see also Section VII, E),... 

The compound (XCI) is naturally, as in an acid chloride, sensitive to hydrolysis. With water it yields amidosulfonic acid and phosphoric acid quantitatively the high stability of the nitrogen-sulfur bond, which is manifestly greater than that of the phosphorus-nitrogen bond, is clear from these results. 

Phosphorus-Nitrogen Bonded Compounds. - Routes to thiophosphinoyl guanidines have been explored further,and additional compounds with P-N bonds have been obtained from the corresponding phosphorus(III) com-pounds sometimes being separable into diastereoisomeric forms. ... 

---