Fig. 3. Circular dichroism and 1H-NMR of norbornapeptides. (A). CD spectra of 1 and diastereomers 2, 4–6, 8, 9 (250 μg mL–1) in aq. 10 mM phosphate buffer pH = 7.0 (black), in 25% trifluoroethanol in aq. 10 mM phosphate buffer pH = 7.0 (red), and in aq. 6 M guanidinium chloride (blue). BBP 3 and 7 existing as equilibrating conformers were not considered. (B). CD spectra of 1, 6 and their side-chain analogs (350 μg mL–1) in 10 mM aq. Phosphate pH 7.0. (C). 1H-NMR metrics on amide proton signals of norbornapeptides. (C). Chemical shift and 3J values for side-chain variations of 1 (left) and 6 (right) and their side-chain analogs 10, 19–22 (to be compared to 1) and 15, 23–26 (to be compared to 6).
