Compound 1, obtained as oil, had the molecular formula C20H32O5 based on the HRESIMS (pos)., showing a quasi-molecular ion peak at m/z 375.2147 (calcd for C20H32O5Na, 375.2147) with five degrees of unsaturation.
Therefore, compound 2 was unambiguously established as 10α-hydroxy-lycoposerramine K. Lycoplanine D (3) has the molecular formula C16H24N2O2 based on its HRESIMS (m/z 277.1914) ([M+H]+, calcd 277.1911) and 13C NMR spectroscopic data.
Compound 7 had a molecular formula of C14H16O6 based on HRESIMS ([M+Na]+ m/z 303.0838, calcd for 303.0839).
Compound 6, a colorless oil, was determined to have a molecular formula of C12H18O3 based on the HREIMS data, m/z 210.1259 [M]+ (calcd for 210.1256).
Molecular formulae were assigned based on previously described rules [35], and the calculated theoretical m/z values of the assigned formulae agreed with measured m/z values with an error value of ≤ 0.5 ppm.
Compound 5, a colorless oil, had the molecular formula of C15H26O2 based on its HRESIMS at m/z 268.1814 ([M + Na]+), which implied the presence of three degrees of unsaturation.
Compound 1 was isolated as a colorless oil and determined to have a molecular formula of C13H20O4 based on the HREIMS data, m/z 240.1361 [M]+ (calcd for 240.1362).
d, 10.5) 19 0.90 (s) 19.6 q Open image in new window Fig. 3 Chair conformation of sugar moiety in 3. Compound 6, a yellow amorphous powder, had a molecular formula of C16H14O7 based on HRESIMS (neg).
Thus, the structure of 1 was established as shown and named rauvotetraphylline F. Open image in new window Fig. 2 Key ROESY correlations of 1 and 2. Compound 2, isolated as amorphous powder, had the same molecular formula as 1 based on HR-ESI-MS (pos)., showing a quasi-molecular ion peak at m/z 568.3031 (calcd for C31H42N3O7, 568.3022).
