Reaction of quercetin (QR) (1) with bromine under various conditions was studied. Interaction of QR with 2–3 equiv. of bromine in glacial acetic acid at 35–40°C for 2–4 h and 20–22°C for 24 h led to the formation of QR 6,8-dibromide (2) (52–54% yields, 96–98% purity by HPLC). Interaction of QR with 2–5 equiv. bromine in absolute ethanol at 0–5°C and 20–22°C for 24 h led to the formation of 3- O-ethyl-QR-2,3,6,8,5′-pentabromide (3) (95–97% purity by HPLC) the output of which depends on the quantity of bromine. It was shown in MDCK cell culture that compound 2 exhibits a moderate inhibitory activity against pandemic influenza virus A/H1N1/pdm09 (EC50 6.0 μg/mL, CTD50 97.7 μg/mL, SI 16). Compound 3 was inactive.

We describe an optimized method for obtaining glycyrrhizic acid (GA, 90.5 ± 1.5 %), which is the main triterpene glycoside of licorice root (Glycyrrhiza glabra L., Gl. uralensis Fisher) extract, and its trisodium and monoammonium salts from a commercial licorice root extract containing 20.0 ± 1.5% GA.

Uraline, a new norditerpenoid alkaloid, was isolated from aerial parts of Delphinium uralense. The structure of 1alpha,7,8-trihydroxy-6beta,14alpha,16beta-trimethoxy-18-N-(2-methyl)succinylanthranoyloxyaconane was ascribed to the new compound on the basis of 1H and 13C NMR, IR, and mass spectra. The known alkaloids methyllycaconitine and delcorine were also isolated from the plant.

Oxidation of the diterpene alkaloids lappaconitine, triacetyllappaconine, and talatisamine by the urea-H 2 O 2 complex (UHP) under various conditions produced the corresponding nitrones.

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