20066-05-1

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Twelve lupane, 18α-oleanane, and des-E-lupane derivatives (1a-5b) were either extracted from natural sources or synthesized from betulinic acid (1a) and betulin (2). Compounds 1b, 1c, 3b, 3c, 4b, 4c, 5a, and 5b were then used as starting materials for further synthesis of a series of pyrazines and benzopyrazines (6a-18); 20 of them are new (6a-6c, 7a-7d, and 10a-18). Activity of pyrazine 6a against the T-lymphoblastic leukemia cell line CEM encouraged us to synthesize several new esters (6b-6d) to study structure-activity relationships with respect to substitution of the carboxyl group at position 28. The synthesized compounds were tested for cytotoxicity against a variety of cancer cell lines of different histogenetic origin, and the results were compared with cytotoxicity of the known starting compounds. Significant cytotoxic activity against A 549, K 562, and multidrug-resistant K 562-tax cell lines was found in pyrazines 6a, 6d, and 6e.

Hydroxycyclopropanation at the ester group in the series of lupane triterpenoids was performed for the first time using 3,3-ethylenedioxybetulonic acid methyl ester and its 20,29-dihydro analog as substrates.

New derivatives of lupane triterpenoids, viz., 20,29-dihydrobetulinic and 3-epi-20,29-dihydrobetulinic acid derivatives containing triphenylphosphonium fragments as substituents were synthesized. These compound considerably exceed betulinic acid in antitu

Triterpenoid betunilic acid is extracted from outer bark of Biscofia javanica blume from Darjeeling hilly region and carried out transformative reaction to introduce oxadiazole moiety to ring A of the triterpenoid which was identified as 28-carbomethoxy lupan (2,3-c)-1′,2′,5′-oxadiazole. The derivative obtained has been selected for its antibacterial and fungicidal activity at different concentrations with respect to the parent compound. The structures of these compounds were established based on spectroscopic (UV, IR, NMR) analysis.

Reflux of 2α-bromo/2,2-dibromolupanone (1/1a), methyl 2α-bromo/2,2-dibromodihydrobetulonate (2/2a) and 2/4α-bromofriedelin (3/3a) with N,N-dimethylaniline (DMA) resulted in the formation of lupanone, methyl dihydrobetulonate and friedelin, respectively in very good yields. The products have been characterized by spectroscopic analysis [IR, NMR ( 1H and 13C) and MS] and optical rotation as well as by comparison with the data reported in literature.

The reaction of lithium in ethylenediamine with 2,2-dibromo (1/1') and 2α-bromo (2/2') derivatives of lupanone (3) and methyl dihydrobetulonate (3') furnishes lupanone/methyl dihydrobetulonate (3/3') and the pyrazine derivative (4/4').

The reduction of terminal double bonds in the side chains on the rings A and E of pentacyclic triterpenoids by means of tris(triphenylphosphine)rhodium chloride permits selective reduction of dienes and labelling with deuterium with a low scattering.The effect of the amount of the catalyst and the solvent used on the rate of reduction was studied in the case of 3β,28-diacetylbetulin.