- Friedelane triterpenoids: Transformations toward A-ring modifications including 2-: Homo derivatives
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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.
- Das, Jayanta,Sarkar, Antara,Ghosh, Pranab
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p. 6673 - 6688
(2018/05/07)
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- Molecular structures and antiviral activities of naturally occurring and modified cassane furanoditerpenoids and friedelane triterpenoids from Caesalpinia minax
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Further investigation of the active components of the chloroform fraction of the seeds of Caesalpinia minax led to the isolation of a new cassane furanoditerpenoid, caesalmin H (1), together with two known furanoditerpenoid lactones, caesalmin B (2) and bonducellpin D (3). Reduction of the naturally abundant caesalmin D (9), E (10) and F (11) resulted in three new furanoditerpenoid derivatives 4-6. Phytochemical study of the stem of the same plant and subsequent reduction afforded two friedelane triterpenoids (7-8), which were identified by spectroscopic methods. Compounds 1-2 and 4-8 were corroborated by single crystal X-ray analysis. The factors governing the reduction of cassane furanoditerpenoids and friedelane triterpenoids were investigated by correlating the crystallographic results with density functional theory. The inhibitory activities of 2-8 on the Para3 virus were evaluated by cytopathogenic effects (CPE) reduction assay.
- Jiang, Ren-Wang,Ma, Shuang-Cheng,He, Zhen-Dan,Huang, Xue-Song,But, Paul Pui-Hay,Wang, Hua,Chan, Siu-Pang,Ooi, Vincent Eng-Choon,Xu, Hong-Xi,Mak, Thomas C.W.
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p. 2161 - 2170
(2007/10/03)
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- Chemical constituents of Argyreia argentea, Millingtonia hortensis and Pyrostegia venusta
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Isolation of five known compounds n-hentriacontanol, β-sitosterol, friedelin, epifriedelinol and epifriedelinol acetate from Argyreia argentea aerial parts; four known compounds nonacosanoic acid, ursolic acid, oleanolic acid and 6-methoxy-5,7,4′-trihydroxyflavone from Millingtonia hortensis flower, and four known compounds lupeol, betulin, betulinic acid and choline chloride from the stem bark of Pyrostegia venusta is reported.
- Dinda,De,Bhattacharya,Arima,Sato,Harigaya
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p. 291 - 293
(2007/10/03)
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- Synthetic secofriedelane and friedelane derivatives as inhibitors of human lymphocyte proliferation and growth of human cancer cell lines in vitro
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Controlled silylation of friedelin (1) from cork smoker wash solids, a byproduct generated during processing of corkboard by steam baking, gave 3-trimethylsiloxyfriedel-2-ene (3) in high yields. Oxidation of 3 with OsO4/NMMO produced 2α-hydroxyfriedelan-3-one (cerin) (5), from which the new 2,3-secofriedelan-2-al-3-oic acid (6) was obtained quantitatively by periodic acid oxidation. Oxidation of 3 with DDQ afforded friedel-1-en-3-one (8). Reductive ozonolysis of 3 gave 2α,3β-dihydroxyfriedelane, pachysandiol A (7). Compound 6 proved to be a potent inhibitor of human lymphocyte proliferation (IC50 = 10.7 μM) and of the growth of a human cancer cell line (GI50 = 5.4-17.2 μM). 13C NMR data for compounds (3, 4, 5, 6a, 7, and 8) are described for the first time.
- Moiteiro,Justino,Tavares,Marcelo-Curto,Florencio,Nascimento,Pedro,Cerqueira,Pinto
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p. 1273 - 1277
(2007/10/03)
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- Cytotoxic terpenoids and flavonoids from Artemisia annua
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The cytotoxic activity of nine terpenoids and flavonoids isolated from Artemisia annua was tested in vitro on several human tumor cell lines. These compounds are artemisinin, deoxyartemisinin, artemisinic acid, arteannuin-B, stigmasterol, friedelin, friedelan-3β-ol, artemetin, and quercetagetin 6,7,3',4'-tetramethyl ether. Friedelane-type triterpenoids were isolated for the first time from this plant. Artemisinin and quercetagetin 6,7,3',4'-tetramethyl ether showed significant cytotoxicity against P-388, A-549, HT-29, MCF-7, and KB tumor cells.
- Zheng
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- SYNTHESIS OF 25-OXYGENATED D:A-FRIEDOOLEANANES FROM D:A-FRIEDOOLEAN-7-Β-OL
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D:A-Friedoolean-25-ol (1) and 25-al (2) have been synthesised from D:A-friedoolean-7β-ol (3).Substituted tetrahydrofuran rings are opened up on treatment with lithium in ethylenediamine to yield the corresponding saturated alcohols.
- Mitra, Bhanusuta,Sen, Manju,Das, Saktipada
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p. 6971 - 6972
(2007/10/02)
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- REDUCTION OF KETONES TO EPIMERIC ALCOHOLS WITH POTASSIUM HYDROXIDE-DIETHYLENE GLYCOL
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Triterpenoid ketones have been reduced to epimeric alcohols on boiling with potassium hydroxide in diethylene glycol. α,β-unsaturated ketone furnished saturated epimeric alcohols.
- Pradhan, B. P.,Hassan, A.,Ray, T.
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p. 2513 - 2516
(2007/10/02)
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- 21α,26-dihydroxy-D:A-friedooleanan-3-one from Salacia reticulata var. Diandra (celastraceae)
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Carbon-13 NMR has been used to detect the position of angular methyl oxygenation and determine the structure of 21α,26-dihydroxy-D:A-friedooleanan-3-one, a new trioxygenated friedooleanane from Salacia reticulata var. diandra and the assignment has been confirmed chemically.
- Kumar, Vijaya,Wazeer, Mohammed I.M.,Wijeratne, Dharmasree B.T.
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p. 2067 - 2069
(2007/10/02)
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- Terpenoids and Related Compounds: Part XXXI - Stereospecific Reduction of Triterpenoid Ketones with Lithium and Ethylenediamine
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Hindered triterpenoid ketones are reduced in excellent yields to the corresponding thermodynamically more stable alcohols on stereospecific reduction with lithium and ethylenediamine.
- Sengupta, Pasupati,Das, Saktipada,Das, Kanchan
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p. 1113 - 1114
(2007/10/02)
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- Lithium-Ethylenediamine as a Reducing Agent
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In a series of triterpenoids, ketones have been converted into sterically more stable secondary alcohols, aldehydes to primary alcohols, hindered esters to acids and isopropenyl groups to isopropyl groups on reduction with lithium in ethylenediamine in high yields.
- Pradhan, Bhim Prasad,Chakrabarti, Dilip Kumar,Chakraborty, Satyajit
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p. 1115 - 1116
(2007/10/02)
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- D:A-Friedooleananes from Elaeodendron glaucum
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Two new trioxygenated D:A-freidooleananes from the stem bark of Elaeodendron glaucum have been shown to be the angular methyl dioxygenated 25,28-dihydroxy-D:A-friedooleanan-3-one (2) and 25-hydroxy-3-oxo-D:A-friedooleanan-28-al (3).
- Weeratunga, Gamini,Kumar, Vijaya,Sultanbawa, M. Uvais S.
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p. 1067 - 1072
(2007/10/02)
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- 3,5,7,3',5'-PENTAHYDROXYFLAVAN AND 3α-METHOXYFRIEDELAN FROM HUMBOLDTIA LAURIFOLIA
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The leaf, bark and timber extractives of Humboldtia laurifolia were investigated and the following compounds have been isolated: O-acetyloleanolic aldehyde, a sitosteryl ester, lupeol, sitosterol, a fatty acid, 5,7,4'-trihydroxyflavone (apigenin), (2R,3R)-3,5,7,3',5'-pentahydroxyflavan and 3α-methoxyfriedelan.The latter two compounds are new natural products.Key Word - Humboldtia laurifolia; Leguminosae; O-acetyloleanolic aldehyde; lupeol; 5,7,4'-trihydroxyflavone; (2R,3R)-3,5,7,3',5'-pentahydroxyflavan; 3α-methoxyfriedelan.
- Samaraweera, Upasiri,Sotheeswaran, Subramaniam,Sultanbawa, M. Uvais S.
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p. 565 - 568
(2007/10/02)
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- TWO NEW ANGULAR METHYL DIOXYGENATED D:A-FRIEDO-OLEANANES
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Two new trioxygenated D:A-friedo-oleananes from Elaeodendron glaucum have been shown to be the angular methyl dioxygenated 25,28-dihydroxy-D:A-friedo-oleanan-3-one(1) and 3,28-dioxo-D:A-friedo-oleanan-25-ol(2) by interconversion and deoxygenation of the alcohol(2) using Lithium-ethylene diamine reduction coupled with spectroscopic methods.
- Weeratunga, Gamini,Kumar, Vijaya,Sultanbawa, M. Uvais S.
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p. 2031 - 2032
(2007/10/02)
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- TRITERPENES AND STEROIDS FROM Ganoderma applanatum
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Five already described triterpenes and steroids were isolated from the fungus Ganoderma applanatum.Its main components are friedelin, ergosta-7,22-dien-3-one and ergosta-7,22-dien-3β-ol, which are accompanied by small amounts of friedoolean-5-en-3-one and ergosterol.Palmitic acid is a further component.
- Protiva, Jiri,Skorkovska, Hana,Urban, Jiri,Vystrcil, Alois
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p. 2710 - 2713
(2007/10/02)
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