A NOVEL ROUTE TO AN AMINOPHOSPHONIC ACID BY THERMOLYSIS OF A POLY(URETHANE PHOSPHONATE). THE BETAIN FORM OF 3-ETHYL-2-HYDROXY-2-OXO-1,4,2-OXAZA-PHOSPHORINANE. STRUCTURE AND PROPERTIES

A poly(urethane phosphonate) was obtained via transesterification of phosphonic acid diesters with hydroxyalkyl carbamate based on propylene carbonate and 2-aminoethanol. Thermolysis of the poly(urethane phosphonate) yielded the betain form of 3-ethyl-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinane. The structure of this novel cyclic aminophosphonic acid monoalkylester was established by C-13{H-1}-, P-31- and P-31{H-1}-NMR-spectra supported by Molecular Modeling (MOPAC93 with AM1 and PM3). Stability-and dissociation constants were determined For the protolytic equilibrium (H2L+, HL, L-) involving the betain of 3-ethyl-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinane.