Significant correlated sequences of OMe-3/
OMe-2/OMe-1/H-11/OMe-10/OMe-9/H-8/H-7/H-6a and H-4/
H-5 were observed in the NOESY spectrum (Figure 1),
confirming the positions of the methoxy groups. Thus, the
structure of 3 was determined as illustrated and named
romucosine G (3). Treatment of (+)-norpurpureine with
triethylamine and methyl chlorocarbonate gave a compound
whose mp, UV, TLC, and 1H NMR data were the
same as those of 3.