Untitled

A-Ring-Modified Triterpenoids and Their Spermidine–Aldimines with Strong Antibacterial Activity

“…Substances were detected by 10% H 2 SO 4 with subsequent heating to 100-120 • C for 2-3 min. Betulonic aldehyde [24], compounds 1 [20], 3 [21], ursonic acid and 4 [22], 11 [23] were obtained according to the methods described previously.…”

“…After completion of the reaction, the mixture was passed through Al 2 O 3 , the organic phase was washed with H 2 O (2 × 30 mL), dried over CaCl 2 and evaporated under reduced pressure to yield crude aldehydes. Then, to a solution of betulonic aldehyde (110 mg, 0.25 mmol) [24] or freshly prepared above aldehydes in anhydrous MeOH (25 mL), spermidine (0.05 mL, 0.25 mmol)) was added and the reaction mixture was heated under reflux for 8 h, then poured into H 2 O (50 mL) and the precipitate was filtered off, washed with water, and dried in air. The products were chromatographed over Al 2 O 3 using CHCl 3 and a mixture of CHCl 3 -EtOH (100:1; 50:1) as eluents to afford compounds 7 (100 mg, 65%) as a yellow powder, 8 (102 mg, 72%) as a beige powder or 9 (109 mg, 70%) as an orange powder.…”

Solid-State Characterization and Biological Activity of Betulonic Acid Derivatives

“…In the field of functionalization and evaluation of biological activities, betulonic acid and its derivatives are by far less studied and reported in literature compared to other triterpenoids. Betulonic acid (or lup-20(29)-en-3-oxo-28-oic, BetO, Figure 1)) and some of its derivatives were previously evaluated for biological activities, showing antiviral [23,24], antitumor and antineoplastic [25,26], hepatoprotective [27], anti-inflammatory [28,29], anti-HCMV activity [30], antimicrobial [31] and immunotropic effects [32].…”

Antineoplastic Agents. 606. The Betulastatins

“…To begin, the synthesis of 7b was carried out as shown in Scheme . Betulin was acetylated, and the resulting diacetate selectively deprotected at C-28 in the presence of K 2 CO 3 and aqueous MeOH to 3- O -acetylbetulin and then oxidized to aldehyde 1 with pyridinium dichromate. − When the aldehyde 1 was reacted with hydroxylamine hydrochloride, the oxime 2 was prepared and subsequently reduced to the corresponding amine 3 , using the reducing system sodium cyanoborohydride, 15% titanium chloride, and ammonium acetate . The N-protected amino acid Boc-Dap ( 4 ) was condensed with amine 3 using the organophosphorous coupling reagent diethylcyanophosphonate (DEPC) to give, following purification, amide 5 .…”