Studies of phosphazenes. Part 13. Thermal rearrangement reactions of some methoxycyclophosphazenes
The methoxycyclophosphazenes [NP(OMe)2]n(n= 3–6) rearrange on heating to give oxocyclophosphazenes, [N(Me)PO(OMe)]n. Isomeric products are formed when n= 4–6. The 1H, 31P, and 13C n.m.r. data for the starting materials and the products are presented. The ethoxy- and n-propoxy-derivatives N3P3(OR)6 do not undergo the above rearrangement. The geminal derivatives N3P3R2(OMe)4(R = Ph or NHBut) on heating yield both fully and partially rearranged products, namely dioxophosphaz-1-enes and oxophosphazedienes, as shown by 270-MHz 1H n.m.r. spectroscopy. The non-geminal derivative N3P3(NMe2)2(OMe)4 gives only the fully rearranged product N3Me3P3(NMe2)2O3(OMe), whose structure has been established from its 1H and 31P n.m.r. spectra.