ABSTRACT
To study the constituents of Karelinia caspia (Pall.) Less, three phenylpropanoid derivatives and other compounds were isolated by silica gel, RP-18 chromatographic methods. Compound 1 was a new phenylpropanoid glycoside named as kareline A. Their structures were determined by spectroscopic analysis, including 1D- and 2D-NMR and mass spectrometry.
ABSTRACT
Identification of natural products has been a big challenge because of their structural complexity and diversity. Recently, with the development of separation materials, more and more complex compounds have been found with small quantity, which causes difficulty in absolute configuration assignment. Now, the computational methods, such as to compute the 13C NMR data and compare them with experimental results, could be used for relative configuration study other methods, for example, to compute optical rotation (OR), or optical rotatory dispersion (ORD), electronic circular dichroism (ECD or CD) or vibrational circular dichroism VCD, could be efficiently used for absolute configuration determinations for chiral compounds, including the derminant computations for chiral acyclic compounds. Now, two or two more methods are applied for the absolute configuration study and exhibit very powerful reliability.