J. Org. Chem. 1990,55, 4657-4663 magnitude mode. Generally 32 transients were acquired for each of 256 increments in t,, which were zero-filled to a 2K X 1K matrix and transformed with pseudoecho weighting. The mixing time was set to 350 ms, and the recycle delay, to 3.0 s. NOESY cross-peak intensities as estimated by peak height were divided by peak intensities for the epindolidione aryl NH to H-1 and the heteroaryl NH to H-4 cross peaks in order to establish relative strengths of signals. The following rating system was used for these ratios: vs, >0.5;s, 0.15-0.5; m, 0.03-0.14; w,
