Beilstein J. Org. Chem.2016,12, 2523–2534, doi:10.3762/bjoc.12.247
Dracocephalumrupestre, have been synthesized in a one-pot reaction. The separation of 2a–d and 3a–d was achieved by preparative HPLC. The four stereoisomers of each natural product were separated by analytical chiral HPLC and their absolute configuration was studied by the combination of HPLC–ECD measurements
and TDDFT–ECD calculations. The synthesized flavonoid alkaloids were further characterized by physicochemical and in vitro pharmacological studies.
Keywords: absolute configuration; Dracocephalumrupestre; dracocephins A–B; ECD calculation; flavonoid alkaloids; HPLC–ECD; Introduction
Flavonoid
stereoisomers by Ren et al. in 2008 from Dracocephalumrupestre [2], which is an herb widely distributed throughout western China and used in folk medicine for the treatment of various conditions including cold, cough, icterohepatitis and laryngalgia. Dracocephins A (±)-2a–d and B (±)-3a–d have been found to be
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Graphical Abstract
Figure 1:
Structures of (±)-naringenin, (±)-dracocephins A1–A4 and B1–B4 with the indication of the absolute ...