SYNTHESIS AND TRANSFORMATIONS OF N-SUBSTITUTED 3-AMINO-PROPANOIC ACIDS .V. PREPARATION OF 2-SUBSTITUTED 3,3-DIPHENYL-3-BENZOYLAMINO PROPANOIC ACIDS

t-Butyl esters of aliphatic carboxylic acids, containing α-hydrogen, combine in the presence of LiNH2 in liquid NH3 with N-benzoyl-diphenylketimine; on saponification by p-toluenesulphonic acid, the resulting esters are converted into the resp. 2-substituted 3.3-diphenyl-3-benzoylamino-propanoic acids. Besides the expected acids, 2.2-disubstituted esters yield on saponification also the resp. β-lactams; among these spiro-β-lactams were found. © 1969 Springer-Verlag.