The room temperature oxidation of betulin by Cr(VI) compounds in aqueous acetone on solid supports such as alumina, zeolites and silica gel has been studied. The oxidation on alumina support leaded to a single product—betulonic acid—in quantitative yield. One hundred percent selective oxidation during 30 min of betulin up to betulonic aldehyde was determined when silica gel support was used. The oxidation of betulin using zeolites as a support gives a mixture of betulonic acid and aldehyde in a 2:1 ratio. It is proposed the selective oxidation up to betulonic acid is due to the influence of Al3+-ions.

Betulin-3,28-diphosphate (BDP) obtained by phosphorylation of betulin using POCl3 has two main structural forms—BDP-1 and BDP-2—which differ in ethanol solubility, melting point, FTIR spectra, thermoanalytical characteristics and biological activity. Betulin-3,28-diphosphate and its sodium salt (Na-BDP) were characterized using 13C and 31P-NMR spectra, powder XRD experiments, as well as differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) methods. The exo-effects at 193 ± 8 °C for ethanol soluble BDP-1 samples (−19.7 ± 0.2 kJ∙mol−1) were about three times less than for ethanol insoluble BDP-2 samples f (−70.5 ± 0.7 kJ∙mol−1). The DSC curves of Na-BDP-1 and Na-BDP-2 characterized the endo-effects having a maximum at 95–112 °C. Water-soluble Na-BDP-1 was obtained as needle-like crystals, unlike poorly crystalline Na-BDP-2, whereas BDP-1 and BDP-2 aged with time and were isolated as amorphous substances. In vitro experiments on rats showed that compared to the control, Na-BDP-1 increased catalase and SOD activity and improved energy metabolism more effectively than Na-BDP-2.

Objective: Studies of composition, stability and antioxidant properties of the betulin-3, 28-diphosphate complexes with dopamine and trisamine. Methods:The betulin-3, 28-diphosphate (BDP) interaction with amines in a water-alcohol medium was studied by using spectral methods and potentiometric titration. Biochemical indexes such as catalase, superoxide dismutase (SOD), lactate dehydrogenase (LDH) activities and malondialdehyde (MDA) level were estimated in experiments on rats.Results: BDP was synthesized using betulin by POCl3 treatment in the presence of pyridine in dioxane. The complexation of BDP with amines was confirmed by the 31 P-NMR and FTIR-spectral data. The stoichiometry of BDP-dopamine complexes was equal to 2:1 and 4:1 and its complexes with trisamine were produced in the ratio 1:1 in a water-alcohol medium. The conditional stability constant К′st of the BDP-trisamine complex is 1130±55 mol•l -1 . BDP-Tris complex improved SOD activity up to 30% and up to 105% in the presence of cytostatic-hydrazine sulfate. The MDA level in erythrocytes decreased up to 57% and in combination with cytostatics (5-fluorouracil and hydrazine sulfate)-up to 11-14%. The catalase activity increased by 44-94% and MDA level in erythrocytes decreased by 22-53% under the action BDP-DA complexes that depends on the dose. Conclusion:The BDP forms stable complexes with trisamine and dopamine that make it possible to use this compound as a component of drug delivery system for high toxicity cytostatics and for readily oxidized catecholamines. It has been shown that both its complexes with amines and the combination with cytostatics enhanced antioxidant activity in an experiment in vitro.

Objective: To study betulin-3,28-diphosphate (BDP) water solubility improved by forming salt complexes with hydrophilic amino alcohols: meglumine as acidosis corrector and xymedon as the water-soluble antioxidant. Methods: We used 13C-, 31P-NMR, UV-spectroscopy and potentiometric titration to study the BDP-amine salt complexes formation and their solubility using HPLC-analysis. Results: The participation of xymedon in the proton transfer reaction with BDP in aqueous solutions was confirmed by the bathochromic shift of the carbonyl band from 299.1 nm to 304.2 nm, and by a hyperchromic effect (molar extinction ε from 8508 to 10 441 l·mol-1·cm-1) in UV-spectra. BDP complexation with meglumine was estimated by UV-spectral molar ratio method at 256 nm. Molar ratio of BDP-amine complexes (1:4) was proved by 31P-NMR. The chemical shift of phosphorus at C-3 atom of BDP (δ =-0.58 ppm) changed to+3.39 ppm, and at C-28 atom (δ =+0.28 ppm)–to+4.60 ppm. BDP solubility increased 100-600 fold according to HPLC-analysis. Conclusion: BDP interaction with amine in an aqueous solution was shown to proceed via a proton transfer due to relatively weak forces such as London forces, hydrogen bonding, electrostatic and hydrophobic interactions. In general, the formation of BDP salt complexes with amines in solution determines BDP water solubility. Water-soluble BDP enables to develop hydrophilic dosage forms.