Oxazoline-containing phosphazene derivatives. Part I: the case of hexakis(4-oxazolinophenoxy)cyclophosphazene

In this paper, the synthesis, characterization, and reactivity of a novel oxazoline-containing cyclophosphazene, hexakis(4-oxazolinophenoxy)cyclophosphazene, C-6-OXA, are reported. This product was synthesized by a two-step procedure that required first the preparation of 2-(4-hydroxyphenyl)-2-oxazoline and then the successive treatment of this compound with hexachlorocyclophosphazene in the presence of NaH (60% oil dispersion). The resulting C-6-OXA was eventually reacted with low-molecular-weight organic molecules, e.g. 4-benzoylbenzoic acid, to form highly photosensitive cyclophosphazenes, and with high-molecular-weight polymers, e.g. poly(ethylene terephthalate), PET, acting as a new type of multifunctional, phosphazene-based chain extender, to produce branched PET macromolecules showing greatly modified rheological properties.