“…As close mimics of biologically relevant systems, and also for consistency with a previous analysis of archazolid A, [10] these compounds were studied in CD 3 OD, in which optimum 1 H NMR signal dispersion was achieved at the highest available field strength (600 MHz). A combination of multiplet analysis, [13] homonuclear decoupling and TOCSY experiments at different mixing times ( Figure 2) were used for determination of all 3 J H,H coupling constants, and information on the spatial relationships between nonadjacent protons was deduced from ROESY experiments. Within the macrocyclic core, all analogues show a characteristic sequence of large (Ͼ8 Hz) and small (Ͻ4 Hz) 3 J H,H coupling constants, together with a series of highly specific transannular NOE correlations, which indicate a high degree of structural rigidity for the macrocycle.…”