22618-86-6Relevant academic research and scientific papers
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.
Applications of Two-Dimensional NMR in Spectral Assignments of Some Friedelanes and Secofriedelanes
Patra, Amarendra,Chaudhuri, Swapan K.,Acharyya, Aditi K.
, p. 85 - 89 (2007/10/02)
Carbon-13 spectral assignments of three friedelanes and nineteen secofriedelanes have been made from mutual correlations, 2D X-H correlation analyses and comparison with the carbon shifts of friedelin, which were firmly established by an INADEQUATE experiment that required reassignment of some of its resonances.Specific methyl and methine proton resonance assignments for some friedelanes, established from X-H correlation studies, are also reported.
