Aminophosphonic and aminophosphinic acid analogues of aspartic acid

4-Oxoazetidin-2-ylphosphonates and phosphinates, obtained from Arbusov reactions of 4-acetoxyazetidin-2-one and 4α-acetoxy-3β-phthalimido-2-one with a variety of phosphites and phosphonites, were hyrdolysed to β-phosphono- and β-phosphino β-alanine (phosphono- and phosphinoaspartic acid) derivatives. In model studies for their incorporation in peptides, conditions for the selective removal of protecting groups for carboxylic acids, phosphonic and phosphinic acids, and amines, in derived di- and tri-peptides were investigated. Alanyl and alanyl alanyl peptide incorporation into bacteria was studied.