X-Ray crystal structures of the N-benzyloxysuccinimide (8) and its unprotec
ted amino analogue (6) have been determined to reveal the conformation of t
he cycle and the constituent phenylalanine. An improved synthesis of C-benz
yl-N-benzyloxysuccinimide (12), a simple, but nevertheless important member
of this class of peptidomimetic, is also presented.