29621-75-8

Upstream product

• 559-74-0 friedelin 
• 471-56-7 4-oxa-3,4-secofriedelan-3-oic acid 
• 5085-72-3 epifriedelanol 
• 161739-59-9 3-trimethylsiloxyfriedel-2-ene 
• 19865-96-4 4-epi-friedelin 

Downstream Products

• 113375-98-7 Acetic acid (R)-1-[(1S,2S,4aS,4bR,6aR,10aR,10bS,12aR)-1-(3,3-diphenyl-allyl)-2,4b,6a,9,9,10b,12a-heptamethyl-octadecahydro-chrysen-2-yl]-ethyl ester 
• 471-56-7 4-oxa-3,4-secofriedelan-3-oic acid 
• 5309-00-2 2-phenyl-3-oxafriedel-1-ene 

Relevant academic research and scientific papers

A SINGLE POT SYNTHESIS OF 3,4-SECO ACID FROM 4,4-DIMETHYL-3-KETO TRITERPENOID

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.

Biovalorization of friedelane triterpenes derived from cork processing industry byproducts

Here, we describe the synthesis, bioactivity screening, and structure-activity relationships of various synthetic triterpenoids prepared from the cork processing byproducts friedelin (1) and 3-hydroxyfriedel-3-en-2- one (2) via oxidative procedures. The synthesis of compounds 2α-trimethylsiloxyfriedelan-3-one (17), friedelin-2,3-lactone (18), friedelin-3-oxime (19), and friedelin-3,4-lactam (20) is also described. We have studied the insecticidal and phytotoxic potential of these compounds, their selective cytotoxic effects on insect and mammalian cells, and their antiparasitic effects. Structural modifications of the A-ring of friedelin (1) improved its insecticidal activity with derivatives 5, 2,3-secofriedelan-2-al-3- oic acid (6), its acetylated derivative 6a, 3β- and 3α- hydroxyfriedelane (9 and 10), 3α-hydroxyfriedel-2-one (11), 4β-hydroxyfriedel-3-one (16), the acetylated 10a, 3,4-secofriedelan-4-oxo- 3-oic-acid (14), lactone 18, and the oxime 19 being stronger insecticides than the parent compound. Methyl-3-nor-2,4-secofriedelan-4-oxo-2-oic acid (12) and its acetylated derivative 12a also showed insecticidal activity in contrast to their inactive parent compound 2. The postingestive effects and cytotoxicity of these compounds suggest a multifaceted insecticidal mode of action. These structural modifications did not result in better phytotoxic agents than the parent compounds except for lactam 20 and yielded several moderately active antiparasite derivatives (seco acids 6, 12, 14, and 4β -hydroxyfriedel-3- one 16) with cytotoxic effects on mammalian cells.

Imines and lactones derived from friedelanes and their cytotoxic activity

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

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.

Design, synthesis and biological evaluation of seco-A-pentacyclic triterpenoids-3,4-lactone as potent non-nucleoside HBV inhibitors

A series of seco-A-pentacyclic triterpenoids-3,4-lactone were synthesized and the anti-HBV activities were evaluated in vitro. Several compounds inhibited the secretion of HBV antigen and the replication of HBV DNA in micromolar level. Compounds D7 and D10, seco-A-oleanane-3,4-lactone, suppressed the HBeAg secretion with IC50 values of 0.14 μM and 0.86 μM respectively, and the inhibitory activities were also confirmed by detecting the fluorescence intensity of FITC-labeled monoclonal mouse HBeAg antibody via flow cytometry. Compounds D7 and D10 as well as B4, ring-A cleaved 3,30-dioic acid, also displayed remarkable inhibition on both HBV DNA replication at the concentration of 25 μM and HBV cccDNA (covalently closed circularDNA) replication with IC50 values of 33.5 μM, 32.7 μM and 12.3 μM respectively.

Novel method for reductive cleavage of triterpenoid lactones with lithium in ethylenediamine

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.

Reaction of triterpenoids with selenium dioxide and hydrogen peroxide

Three different triterpenoid ketones, viz, lupanone (1), methyldihydrobetulonate (2) and friedelin (3) have been converted into their ε-lactones on oxidation with selenium dioxide and hydrogen peroxide. 1 has also been converted into the corresponding δ-lactone with this reagent.

Studies on triterpenoids: Conversion of friedelanones into some secofriedelanes

Baeyer-Villiger oxidation of friedelin (1), cerin (3), its acetate (4) and canophyllol (7) with m-chloroperbenzoic acid yields friedelolactone (2), 2α-hydroxyfriedelolactone (5), 2α-acetoxyfriedelolactone (6) and apetalactone (8), respectively.However, 3α-hydroxyfriedelan-2-one (12) and its acetate (13) give a 2,3:3,4-disecofriedelane (14) under similar conditions.The formate ester so produced affords a methyl ester (15) upon treatment with diazomethane while basic hydrolysis and acidification leads to a nor-δ-lactone (16).Sodium borohydride reduction of friedelolactone, 2α-hydroxyfriedelolactone and the nor-δ-lactone leads to reductive opening of the lactone ring.CrO3/py oxidation of 3,4-secofriedelan-3,4-diol (17), produced from friedelolactone, yields 3,4-secofriedelan-3-ol-4-one (23).Basic hydrolysis of friedelolactone gives a hydroxy acid (25) which undergoes CrO3/py oxidation to a 4-oxo-compound (28).The latter (28) forms a methyl ester (29) and also undergoes Baeyer-Villiger oxidation to an acetate (30) which on hydrolysis affords another nor-δ-lactone (31).

The Reaction of Lupane and Friedo-Oleanane Type Triterpenes with m-Chloroperbenzoic Acid

Lupane-3β,28-diol, lupan-3β-ol, and friedelan-3β-ol were treated with m-chloroperbenzoic acid (mCPBA) in refluxing chloroform to afford corresponding lactones in one step, while lupane-3β,28-diyl, diacetate, lupan-3β-yl acetate, and friedelan-3β-yl acetate to give hydroxylated or keto derivatives.Similar reaction of dendropanoxide with mCPBA yielded 6β-, 7β-, 21α-, and 22β-hydroxylated compounds.

Assignment of Carbon-13 Nuclear Magnetic Resonance Spectra of Some Friedelanes

Carbon-13 resonance assignments of cerin acetate, 2α-pyridine-N-oxyfriedelan-3-one, epi-cerin and its acetate, 3α-hydroxyfriedelan-2-one and its acetate, 3-hydroxyfriedel-3-en-2-one and its acetate, friedelane-3,7-dione, 3β- hydroxyfriedelan-7-one, canophyllol, friedelolactone and friedelolactone-2α-yl acetate, friedelane-2α,3α-diol and its diacetate, friedelane-2β,3α-diyl diacetate, pachysandiyl-A diacetate and friedelane-2β,3β-diyl diacetate have been made.The carbon signals of 3-oxofriedelan-29-ol and its acetate, methyl 3-oxofriedelan-29-oate, 3-oxofriedelan-30-ol, maytenfoliol, maytensifolin-A, maytensifiolin-B, pachysonol and pristimerin reported in the literature have also been considered for their specific resonance assignments.A few signal assignments of some friedelanes, viz. friedelan-28-ol, friedelan-29-ol, friedelan-30-ol, friedelan-29-al, 3-oxofriedelane-21α,26-diol and zeylasterone, reported recently by others, are unusual and have been reviewed.KEY WORDS 13C NMR Friedelanes Revised assignments