of 3 can be readily verified by app

of 3 can be readily verified by applying the same analysis carried
out for compound 2 (Figure 1). In compound 3, NOEs were
observed between H-18/H-15 and 19-OMe/H-21, while NOEs
between H-18/H-21 and 19-OMe/H-15 were not seen. In addition,
the paramagnetic deshielding experienced by H-15 in 2 was now
observed for H-21 instead in 3 (Figure 1).
Kopsamidine A (4) was obtained as a colorless oil, [R]D +97 (c
0.15, CHCl3). The IR spectrum showed bands at 3447, 3350, and