Abstract
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 13C{1H}-, 31P- and 31P{1H}-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.