29621-75-8Relevant articles and documents
A SINGLE POT SYNTHESIS OF 3,4-SECO ACID FROM 4,4-DIMETHYL-3-KETO TRITERPENOID
Pradhan, Bhim P.,Chakraborty, Satyajit,Weyerstahl, Peter
, p. 5463 - 5466 (1989)
Oxidation of 4,4-dimethyl-3-keto triterpenoid with m-CPBA in presence of p-TsOH furnishes 3,4-seco triterpenoid acid whereas 4-mono-methyl-3-keto-triterpenoid affords only the ε-lactone under the identical condition.
Imines and lactones derived from friedelanes and their cytotoxic activity
Aguilar, Mariana G.,Duarte, Lucienir P.,Evangelista, Fernanda C. G.,Sabino, Adriano P.,Sousa, Grasiely F.,Vieira Filho, Sidney A.
, p. 810 - 815 (2020)
Friedelan-3-one (1) and friedelane-3,16-dione (2) isolated from leaves and branches of Maytenus robusta Reissek were subjected to structural modifications via nucleophilic addition to the carbonyl group and Baeyer-Villiger oxidation in order to synthesize potential cytotoxic compounds. The oximes friedelane-3-hydroxyimino (3) and 3-hydroxyiminofriedelan-16-one (4) together with the lactones friedelane-3,4-lactone (5) and 3,4-lactonefriedelan-16-one (6) were characterized by IR and NMR spectroscopic analyses. Compounds 4 and 6 are reported for the first time. Cytotoxic screening via MTT assay in human leukemia cell lines (THP-1 and K562) demonstrated no significant improvement of compounds 3-6 when compared to the starting materials. Only compounds 3 and 5 demonstrated an improvement against K562 cells. However, the same assay on ovarian and breast cancer cell lines (TOV-21G and MDA-MB-231) showed a reduction in the IC50 for compounds 4-6, indicating that ring A modifications may enhance the biological potential.
Friedelane triterpenoids: Transformations toward A-ring modifications including 2-: Homo derivatives
Das, Jayanta,Sarkar, Antara,Ghosh, Pranab
, p. 6673 - 6688 (2018/05/07)
Friedelin and its derivatives, commonly known as friedelane triterpenoids, exhibit potential biological effects ranging from antimicrobial to anticancer to anti-HIV. To modify the A-ring of the pentacyclic triterpenoid, various transformative scopes have been utilized. Herein, some simple unprecedented transformative protocols have been accomplished towards furnishing 42 (25 new) A-ring modified pentacyclic friedelane triterpenoids. It is worth noting that the modifications include the all-new 2-homo derivatives. The one-pot BF3·OEt2-mediated oxidative transformation of friedelin to yield friedel-3-enol acetate as the major product was one of the key reactions. A group of isomeric A-ring modifications was produced on the basis of simple transformations on suitable friedelane-based molecules. The syntheses of the novel 2-homofriedelanes were envisioned from the transformative reactions of the designed triterpenoid 3-chlorofriedel-2-ene-2-carbaldehyde, which was isolated as the major product from the reaction of friedelin with the novel Vilsmeier-Haack reagent. New A-ring modified derivatives were also obtained due to further interesting transformations of 3-chlorofriedel-3-ene, isolated as side products from the same reaction. Again, considering the scope of the 3-chloro-2-enal moiety associated with the A-ring of the triterpenoid, some heterocycle-linked- (bonded to C3) 2-homofriedelane triterpenoids were synthesized. Various common reaction strategies were employed on suitable substrates to finally achieve a series of C2,C3-; C3,C4- and C2,C3,C4-functionalized as well as 2-homofriedelane triterpenoids with just one to four efficient steps.
Novel method for reductive cleavage of triterpenoid lactones with lithium in ethylenediamine
Pradhan, Bhim Prasad,Chakraborty, Dilip Kumar,Roy, Animesh
, p. 721 - 725 (2007/10/02)
Sterically hindered γ-lactones furnish mainly the saturated carboxylic acids whereas δ-lactones with less hindrance yield the diols in higher percentage compared to the acids. ε-Lactones, however, furnish the diols exclusively.The reduction is drastic and effective when other methods fail.
