to H-9 (Table 4, Supporting Information). A secondary
hydroxyl group was placed at HO-1â, on the basis of the
three-bond connectivities encountered in the HMBC spectrum
between the carbinyl proton signal at δ 4.20 (br s;
W1/2 ) 6.0 Hz; δ 65.9 d) with C-3 and C-5 and because of
the spatial correlation in the ROESY spectrum with the
H-20 signal. The other carbinyl proton signal at δ 4.51 (s;
δ 65.9 d) gave, among others, three-bond connectivities
with the C-7 and C-17 carbon resonances in the HMBC
experiment and a correlation in the ROESY spectrum with
the one-proton resonance at δ 2.18 (br d, J ) 11.1 Hz; δ
38.1 d) that was assigned to H-14, because of the threebond
correlation shown in the HMBC experiment between
H-9 and H-7â with the 13C NMR signal at δ 38.1, for C-14.
These observations were consistent with the presence of a
HO-15â function in the molecule. The remaining NMR
signals were in agreement with the proposed structure of
4, and the assignments were made on the basis of the 2D
NMR data (Table 2, and Tables 1 and 2, Supporting
Information) and by comparison with the spectra of cossonidine.11
Thus, stronger high-field chemical shifts observed
in carbons C-14 (∆δ ) -5.5) and C-15 (∆δ ) -5.7)
than in carbons C-5 (∆δ ) -2.3) and C-9 (∆δ ) -1.6) were
noteworthy when compared with those of cossonidine due
to the γ-gauche effect exerted by the alcohol group at C-7
over C-14 and C-15 in the R configuration.12,13