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Fifty-one derivatives of lupeol, betulin, betulonic and acanthochlamic acids modified at C3, C20 and C28 of the lupane core including four new ones (37, 49 –51) and forty-seven previously synthesized derivatives (1 – 36, 36 – 48) were screened for their in vitroanti-influenza type A (H1N1, H3N2 and H5N1) activity at the NIAID. The selectivity index (SI) against Flu A for tested triterpenoids ranged from > 20 to 0. Betulonic acid 2-aminopyridinylamide was a leader being active against H1N1, H3N2 and H5N1 with SI > 20, 1.8 and 5.3, respectively. The betulonic acid methoxy- and nitro-substituted benzalhydrazides showed selectivity only against H5N1, while lupeol and 3-oximino-betulonic acid benzalhydrazides were active against three types of Flu A. A-seco-aminoderivatives were more effective than the initial acanthochlamic acid against H1N1, but practically inactive against H3N2, with bis-N-methylpiperazinylamide as a leader in this series. Triterpenoids with a long-chain substituent at C17 containing amide or hydrazide bonds with aromatic or heterocyclic fragments exert positive influence on the activity.

An one-step and efficient access to the new dammarane A-quinolones by ozonolysis of 2,3-indolodipterocarpol at 0°C through the 1,3-dipolar cycloaddition of ozone to the C2-C3 double bond of the triterpenoid core is reported. In the case of oxidation in AcOH, two spiroindoles were identified as a result of 1,2-cycloaddition of ozone to the C2-C3 double bond with following intramolecular rearrangements of 2,3-epoxy-intermediate. The structures of four new compounds were established by 1H, 13C NMR, COSY, NOSY, HMBC and HSQC analyses.

A variety of new and earlier synthesized lupane, oleanane, ursane and dammarane triterpenoids have been investigated for their inhibitory activity against α-glucosidase. 2,3-Indole-21β-acetyl-20β,28-epoxy-18α,19βH-ursane and 3-oxo-3A-homo-3a-aza-20(S)-hydroxydammar-24(25)-ene were synthesized for the first time. The compounds 3, 4, 8–11and 14demonstrated strong in vitroinhibitory activity towards α-glucosidase with IC50values of 37.5–115.1 μM. 3-Deoxy-3a-homo-3a-aza-28-cinnamoyloxy-20(29)-lupene, with an IC50of 6.67 μM was 60-fold more active than the market drug acarbose.

A one-pot synthesis of a hybrid triterpenoid-steroid molecule, hollongdione (22,23,24,25,26,27-hexanordammar-3,20-dion), was achieved in a yield of 89%, based on the selective dehydration of dipterocarpol following ozonolysis. The structure of hollongdione was confirmed by X-ray analysis for the first time. Dammar-20(22),24(25)-dien inhibited the growth of Mycobacterium tuberculosis(strain H37Rv) in vitrowith a MIC of 50 μg/mL.

An access to oxyfunctionalized quinopimaric acid derivatives is reported. The ozonolysis of methyl dihydroquinopimarate occurs through 1,2-cycloaddition of ozone to the bridging double bond followed by intermolecular rearrangements and formation of nontrivial 4β-hydroxy-4α,14α-epoxy-13(15)-ene derivative 2. The oxidation of methyl furfurilydene dihydroquinopimarate with ozone led to anhydride 5and unexpected carboxymethyl substituted cyclopentane lactone 6. The structure of compound 6was confirmed by X-Ray analysis of its methyl ester.