Abstract
α- and γ-phosphonic analogues of glutamic acid were separated to give all enantiomers. 2-Amino-4-phosphonobutyric acid enantiomers were separated as 2-N-benzoylamino-4-diethylphosphonobutyric acid derivatives by the action of papain. Resolution of 4-amino-4-phosphonobutyric acid was performed by crystallization of 4-N-carbobenzoxyamino-4-diethylphosphonobutyric acid salts of both optically active 1-phenylethylamines. Enantiomers of 4-amino-4-phosphonobutyric acid as N-carbobenzoxydiethyl-phosphono derivatives, as N-carbobenzoxy-diethylphospho DCHA salts and as free amino acids are described.