Synthesis of C17-[5-methyl-1,3]-oxazoles by N-propargylation of triterpenic acids and evaluation of their cytotoxic activity.

A series of unexpected triterpenic C17-[5-methyl-1,3]-oxazoles along with targeted N-propargylamides was synthesized by an interaction of acid chlorides with propargylamine hydrochloride. We proposed that the formation of methyl oxazole passes through an alternative pathway by the participation of the terminal alkyne carbon atom and acid chloride intermediate with following intramolecular rearrangements. The synthesized compounds were evaluated for their cytotoxicity at the U.S. National Cancer Institute. 28-Nor-17-(5-methyloxazol-2-yl)-2-cyano-2,4-seco-3-nor-lup-4(23),20(29)-diene has demonstrated the highest activity with GI50 ranged from 1.03 to 16.4 µM against different cancer cell lines. Molecular docking in Kelch domain of Keap1 protein was performed to study a possible molecular target. Thus, we have shown for the first time that triterpenic C17-[5-methyl-1,3]-oxazoles are alternative products of the interaction of triterpenic acid chlorides with propargylamine hydrochloride and they have an advantage over corresponding N-propargylamides as cytotoxic agents.

[Synthesis and pharmacological activity of amides and ozonolysis product of maleopimaric acid].

The synthesis of a new group of maleopimaric acid amides containing fragments of the methyl esters of amino acids, aliphatic amines, imidazole and N-methylpiperazine was carried out. Ozonolysis of methyl maleopimarate flows through the cleavage of double bond C18(19) and the disclosure of anhydrous cycle with formation of secotriacid. As a result of screening of anti-inflammatory and antiulcer activity of maleopimaric acid derivatives new effective compounds such as methyl esters of maleopimaric acid and product of ozonolysis - diterpenic secotriacid, maleopimaric acid amide with L-leucine were revealed. An important advantage of the compounds studied is the low toxicity and the presence of bidirectional activity in the absence of adverse effects on the animal.

[Synthesis and antiviral activity of lupane triterpenoids with modified cycle E].

A reductive transformation of the peroxide products of ozonolysis of derivatives of 3beta-O-acetyl-22(17-->28)-abeo-lupa-17(28),20(29)-diene and the subsequent intramolecular ketalization led to a compound with a trioxane fragment. This is a new approach to a skeletal modification of triterpenoid cycle E. An activity of the synthesized compounds was found toward the viruses of type A influenza and herpes simplex.