Enantiospecific activity of tetracyclic PAF-antagonists

The syntheses of two enantiomeric tetracyclic compounds, the thieno[3,2-f][pyrrolo[2,1-c][1,2,4]triazolo[4,3-a][1,4]diazepines 10a and 10b are described. Testing of these enantiomers as inhibitors of platelet activating factor (PAF) revealed good enantiospecificity, meaning that one enantiomer is responsible for the observed biological activity.     

Pentacyclic laddersiloxane

A novel method which effects ring extension of the ladder oligosilsesquioxanes was developed. By applying this method, we synthesized the first functionalized tricyclic laddersiloxanes and pentacyclic laddersiloxane. The reaction of (i-PrSi(OH)O)4 with (i-PrPhClSiO)2 in pyridine gave the tetraphenyl tricyclic laddersiloxane. Following dephenylchlorination with AlCl3/HCl, and hydrolysis enabled us to isolate the tetrahydroxyl tricyclic laddersiloxane in good yield. We repeated the similar reaction from this tetrahydroxyl laddersiloxane, and the first pentacyclic laddersiloxane was obtained. The structures of the tetraphenyl and tetrahydroxyl tricyclic laddersiloxanes, and pentacyclic laddersiloxane were determined by X-ray crystallography.     

Design,Synthesis and Biological Evaluation of Pentacyclic Triterpene Dimers as HCV Entry Inhibitors

A series of triterpene dimers bearing different scaffold were designed and synthesized via CuAAC reaction. Their anti‐HCV entry activities were evaluated by HCVpp and VSVpp entry assays. It was found that echinocystic acid (EA) and its dimer were still necessary for maintaining anti‐HCV entry activity, and replacement of EA by other triterpenes might significantly decrease its anti‐viral activities. Using a linker bearing a piperazine group, compound 14 dramatically increased its potency with IC₅₀ at 2.87 nmol/L. In addition, the undesired hemolytic effect of all these compounds was removed.     

Pentacyclic Triterpenoid Saponins from Silene viscidula

Three new pentacyclic triterpenoid saponins, viscidulosides A and B ( 1 and 2 , resp.), and silenoviscoside D ( 3 ), were isolated from the roots of Silene viscidula, together with two known saponins, sinocrassulosides VIII and IX ( 4 and 5 , resp.). Their structures were elucidated by spectroscopic data and chemical methods. Compounds 1 / 2 and 4 / 5 were two inseparable mixtures, which are glycosides of quillaic acid whose fucose residue is acylated by (E)‐ or (Z)‐4‐methoxycinnamic acid.     

天然五环三萜有机功能分子

天然五环三萜在自然界中广泛存在,由六个异戊二烯单元组成,可以从动植物中分离获取。因具有手性刚性骨架、多反应位点、独特组装性能、良好生物相容性及药理活性,其在超分子化学、智能材料、界面化学、药物传输等领域有着不可忽视的潜力。本文基于课题组近年来在天然五环三萜有机功能分子方面的工作,概述了含甘草次酸和甘草酸骨架的功能小分子和高分子的设计、合成及其在水凝胶、有机凝胶、有机-无机复合凝胶、手性材料、温敏和自愈合材料、农用Pickering乳液、准聚轮烷等方面的应用。     

New Pentacyclic Triterpenoids from Centella asiatica

Three new pentacyclic triterpenoids, named centellasaponins G, H, and F ( 1 – 3 , resp.), together with four known compounds, 4 – 7 , were isolated from the whole plants of Centella asiatica. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D‐ and 2D‐NMR and HR‐MS experiments, and by comparison with literature data.     

Pentacyclic Triterpene Profile and Its Biosynthetic Pathway in Cecropia telenitida as a Prospective Dietary Supplement

Promising research over the past decades has shown that some types of pentacyclic triterpenes (PTs) are associated with the prevention of type 2 diabetes (T2D), especially those found in foods. The most abundant edible sources of PTs are those belonging to the ursane and oleanane scaffold. The principal finding is that Cecropia telenitida contains abundant oleanane and ursane PT types with similar oxygenation patterns to those found in food matrices. We studied the compositional profile of a rich PT fraction (DE16-R) and carried out a viability test over different cell lines. The biosynthetic pathway connected to the isolated PTs in C. telenitida offers a specific medicinal benefit related to the modulation of T2D. This current study suggests that this plant can assemble isobaric, positional isomers or epimeric PT. Ursane or oleanane scaffolds with the same oxygenation pattern are always shared by the PTs in C. telenitida, as demonstrated by its biosynthetic pathway. Local communities have long used this plant in traditional medicine, and humans have consumed ursane and oleanane PTs in fruits since ancient times, two key points we believe useful in considering the medicinal benefits of C. telenitida and explaining how a group of molecules sharing a closely related scaffold can express effectiveness.     

Three New Pentacyclic Triterpenoids from Lantana camara

Three new pentacyclic triterpenes ursoxy acid ( 1 ), methyl ursoxylate ( 2 ), and ursangilic acid ( 3 ), along with three known compounds dotriacontanoic acid, oleanolic acid acetate, and tetracosanoic acid, were isolated from the aerial parts of Lantana camara Linn . Structures of the new compounds were elucidated by chemical transformation and spectral studies including 1D (¹H‐ and ¹³C‐NMR) and 2D (COSY‐45, NOESY, J‐resolved, HMQC, and HMBC) NMR spectroscopy.     

Two New Pentacyclic Triterpenes from Abelmoschus esculentus

Two new pentacyclic triterpenes, (3β,21β)‐19,21‐epoxylup‐20(29)‐en‐3‐yl acetate ( 1 ) and (3β)‐9,18‐dihydroxyolean‐12‐en‐3‐yl acetate ( 2 ), were isolated from Abelmoschus esculentus (L.) Moench . Their structures were determined on the basis of detailed analyses of their 1D‐ and 2D‐NMR‐spectroscopic and MS data.     

Synthesis of Pentacyclic Framework of Herquline A

The highly strained bowl-shaped pentacyclic structure of herquline A has rendered it one of the most difficult problems in organic synthesis yet to be solved. The challenges associated with the synthesis of herquline A have been well documented in four Ph.D. dissertations and in multiple reports regarding syntheses of its structurally simpler congeners. Herein, we report the construction of the pentacyclic core of herquline A that contains both N10−C2 and C3−C3′ bonds. The key for success was the development of the tandem aza-Michael addition/enolate capture protocol that set the stage for subsequent palladium catalyzed C3(sp²)−C3′(sp²) coupling reaction. Ensuing oxidative dearomatization of the left aryl ring allowed the formation of the pentacyclic diketone core of herquline A.     

A New Pentacyclic Triterpene from Ecdysanthera Rosea

D-friedours-14-en-11α, 12α-epoxy-3β-yl palmitate (1), a new pentacyclic triterpene of the ursane series, was isolated from the aerial parts of Ecdysanthera rosea, and the structure was elucidated on the basis of the spectral data. The partial synthesis of this compound from α-amyrin acetate via a few steps was also achieved.     

Pentacyclic and Hexacyclic Osmaarynes and Their Derivatives

Although osmabenzyne, osmanaphthalyne, osmaphenanthryne, and osmaanthracyne have been previously reported, the synthesis of polycyclic osmaarynes is still a challenge. Herein, we report the successful synthesis of the first pentacyclic osmaarynes (pyreno[b]osmabenzynes 1 a and 2 a ) and hexacyclic osmaaryne (peryleno[b]osmabenzyne 3 a ). Nucleophilic reaction of osmaarynes was used to obtain the corresponding pyreno[b]osmium complexes ( 1 and 2 ) and peryleno[b] osmium complex ( 3 ), which exhibited near-infrared luminescence and aggregation-induced emission (AIE) properties. Complexes 2 and 3 are resistant to photodegradation, and complex 2 has better photothermal conversion properties than 3 .     

Three New Pentacyclic Triterpenoids from Centella asiatica

Three new pentacyclic triterpenoids, named centellasaponin I ( 1 ), centellasaponin J ( 2 ), and centellasaponin E ( 3 ), together with three known compounds, were isolated from the whole plants of Centella asiatica. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D‐ and 2D‐NMR and HR‐MS experiments, and by comparison with literature data.     

Pentacyclic triterpenoids from leaves of Excoecaria agallocha

A new oleanane-type triterpenoid (1) and five known pentacyclic triterpenoids (2-6) were isolated from the leaves of Excoecaria agallocha. Their structures were elucidated by spectroscopic analyses. The new compound was characterized as 3beta-[(2E,4E)-5-oxo-decadienoyloxy]-olean-12-ene (1). Compounds 1-6 were found inactive in vitro against several human cancer cell lines.     

Two New Pentacyclic Triterpenes from Sabia parviflora

Two new pentacyclic triterpene acids,1α,3β-dihydroxyl-olean-12-en-28-oic acid and 1α，2α,3β-trihydroxyl-olean-12-en-28-oic acid, were isolated from the arial parts of Sabia parviflora.     

Two New Pentacyclic Triterpenoids from Centella asiatica

Two new pentacyclic triterpenoids, named centelloside D ( 1 ) and centelloside E ( 9 ), together with the seven known compounds 2 – 8 , were isolated from the whole plants of Centella asiatica. Compound 5 was reported for the first time from this genus. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D ‐ and 2D ‐NMR, and HR‐MS experiments, and by comparison with literature data. Compounds 1 – 4, 6 , and 8 did not show any cytotoxicity against L929 (mouse embryonic fibroblast).     

Synthesis of New Sulfur-Substituted Pentacyclic 1,2,4-Triazolopyrimidine Derivatives

Russian Journal of Organic Chemistry - Pentacyclic heterocyclic compounds containing a 1,2,4-triazole ring have been synthesized from...     

Pentacyclic triterpenoids from the mangrove plant Rhizophora stylosa

Seven pentacyclic triterpenoids including 3beta-O-(E)-coumaroyl-15alpha-hydroxy-beta-amyrin (1), 15alpha-hydroxy-beta-amyrin (2), 3beta-taraxerol (3), 3beta-taraxerol formate (4), 3beta-taraxerol acetate (5), 3beta-O-(E)-coumaroyl-taraxerol (6), and 3beta-O-(Z)-coumaroyl-taraxerol (7) were isolated and identified from the stems and twigs of the mangrove plant Rhizophora stylosa. The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data. Among these metabolites, compound 1 is a new oleanane-type triterpenoid coumaroyl ester, while compound 4 is a new natural product obtained here as an isolated substance for the first time. The full spectroscopic detail of compound 4 is also reported here for the first time.