Table 1.

Physicochemical properties of 1–3.

	1	2	3
Appearance	White powder	White powder	White powder
Molecular weight	653	603	519
Molecular formula	C37H51NO9	C37H49NO6	C32H41NO5
HR-ESI-MS (m/z)
Calcd	654.3642 [M + H]+	604.3625 [M + H]+	520.3067 [M + H]+
Found	654.3637 [M + H]+	604.3638 [M + H]+	520.3063 [M + H]+
${{\mathrm{UV}}_{\mathsf{\lambda }}}_{\max }^{{\mathrm{CH}}_3\mathrm{OH}}\mathrm{nm}\left(\log \mathsf{\epsilon }\right)$	213 (4.2), 248 (4.3), 290(3.7)	230 (3.5), 283 (3.0)	227 (4.4), 280 (3.7)
${\mathrm{IR}}_{\max }^{\mathrm{KBr}}{\mathrm{cm}}^{-1}$	3413, 2977, 2930, 1718	3449, 2979, 2930, 1458	3380, 3004, 2931, 1681
${\left[\mathsf{\alpha }\right]}_{\mathrm{D}}^{\mathrm{t}}\left(\mathrm{c}=0.1{\mathrm{CH}}_3\mathrm{OH}\right)$	−16.6 (t = 25)	−4.0 (t = 23)	−27.8 (t = 25)