The unsaturated part of the 13C NMR spectrum showed the presence of three
carbonyl groups at dC 173.5 (C-AcNH), 174.0 (C-60) and 179.9 (C-30)
together with one tetrasubstituted double bond at dC 128.9 (C-8)
and 141.3 (C-9) and a gem-disubstituted double bond at dC 157.7 (C-
24) and 106.9 (C-241).