1-AMINO-1-ARYL- AND 1-AMINO-1-HETEROARYL-METHANEPHOSPHONIC ACIDS AND THEIR N-BENZHYDRYL-PROTECTED DIETHYL ESTERS: PREPARATION AND CHARACTERIZATION

N-Benzhydryl-protected diethyl esters of 1-amino-1-aryl- (phenyl, cumyl, p-dimethylaminophenyl, piperonyl, 1'-naphthyl, 9'-anthryl, T-pyrenyl) and 1-ainino-1-heteroaryl- (furyl, 2'-thienyl, X-thienyl, 2'-pyrrolyl)-methanephosphonic acids, prepared by the addition of diethyl phosphite to the corresponding benzhydryl imines, have been isolated, purified, and characterized. The presence of chiral alpha-carbon and prochiral phosphorus in these esters gives rise to complicated features in their NMR spectra, which are discussed. Hydrolysis of the crude 1-aryl compounds in situ gave modest yields of the corresponding aminophosphonic acids (except for 1'-pyrenyl). Of the 1-heteroaryl derivatives, only the 2'-thienyl compound gave the expected aminophosphonic acid; in other cases, alternative modes of decomposition may occur under hydrolytic conditions. NMR and mass spectral data are given for all products.