N-Protected, conformationally constrained, eight-membered ring containingcyclicdipeptides derived from methyl cyclo-[(R)-cysteinyl-(R)-penicillamine] contain a cis amide bond, whilst the corresponding peptides derved from cyclo-[(R)-cysteinyl-(S)-penicillamine] contain a transamide bond.
Eight membered ring containing, conformationally constrained peptides derived from cyclo-[(R)-cysteinyl-(R)-penicillamine] contain a cis amide bond, whilst the diastereomeric peptides derived from cyclo-[(R)-cysteinyl-(S)-penicillamine] contain a trans amide bond.