- Wittig Olefination Using Phosphonium Ion-Pair Reagents Incorporating an Endogenous Base
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Despite common perception, the use of strong bases in Wittig chemistry is utterly unnecessary: we report a series of novel ion-pair phosphonium carboxylate reagents which are essentially "storable ylides". These reagents are straightforwardly prepared in excellent yields, and their fluxional nature permits clean olefination of a broad range of aldehydes and even hemiacetals.
- Vetter, Anna C.,Gilheany, Declan G.,Nikitin, Kirill
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p. 1457 - 1462
(2021/03/08)
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- Iron-Catalyzed Nitrene Transfer Reaction of 4-Hydroxystilbenes with Aryl Azides: Synthesis of Imines via C=C Bond Cleavage
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C=C bond breaking to access the C=N bond remains an underdeveloped area. A new protocol for C=C bond cleavage of alkenes under nonoxidative conditions to produce imines via an iron-catalyzed nitrene transfer reaction of 4-hydroxystilbenes with aryl azides is reported. The success of various sequential one-pot reactions reveals that the good compatibility of this method makes it very attractive for synthetic applications. On the basis of experimental observations, a plausible reaction mechanism is also proposed.
- Peng, Yi,Fan, Yan-Hui,Li, Si-Yuan,Li, Bin,Xue, Jing,Deng, Qing-Hai
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supporting information
p. 8389 - 8394
(2019/10/16)
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- Tetrahydropyrrolization of Resveratrol and Other Stilbenes Improves Inhibitory Effects on DNA Oxidation
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The inhibitory effect of resveratrol on DNA oxidation caused by 2,2′-azobis(2-amidinopropane hydrochloride) (AAPH) was found to be enhanced if the C=C bond in resveratrol was converted into tetrahydropyrrole by reaction with azomethine ylide (CH2=N+(CH3)CH2?). This encouraged us to explore whether the inhibitory activities of other stilbenes could also be increased by the same method. We found that the inhibitory effects of the tetrahydropyrrole derivatives on AAPH-induced oxidation of DNA were higher than those of the corresponding stilbenes, because the tetrahydropyrrole motif can provide hydrogen atoms to be abstracted by radicals. Therefore, the tetrahydropyrrolization offered an advantage for enhancing the antioxidant effects of stilbenes. Notably, (CH3)3SiCH2N(CH3)CH2OCH3(in the presence of CF3COOH) and (CH3)3NO (in the presence of LiN(iPr)2) can be used to generate azomethine ylide for the tetrahydropyrrolization of stilbenes containing electron-withdrawing and -donating groups, respectively.
- Bao, Liang-Liang,Liu, Zai-Qun
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p. 1617 - 1625
(2016/08/28)
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- THERAPEUTIC AGENTS FOR SKIN DISEASES AND CONDITIONS
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The present invention relates to method(s) of treating a subject afflicted with a skin disease or condition, the method comprising administering to the subject or patient in need a composition comprising a therapeutically effective amount of a substituted cis or trans- stilbene or a stilbene hybrid. A method of treating or reducing the likelihood of a skin disease or condition in a patient is an additional embodiment of the present invention. Preferred pharmaceutical compositions of the invention include nanoemulsions comprising a therapeutically effective amount of a substituted cis or trans-stilbene or stilbene hybrid and at least one antibiotic.
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Page/Page column 36; 48-49; 51
(2015/06/18)
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- Cu(acac)2-catalyzed synthesis of functionalized bis(arylmethyl)zinc reagents and their olefination reaction with aromatic aldehydes
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An efficient and facile copper(II) acetylacetonate catalyzed synthesis of functionalized bis(arylmethyl)zinc reagents from arylmethyl halides and their olefination reaction with aromatic aldehydes is reported. Aluminum trichloride was found to be the key ingredient in these reactions and (E)-stilbenes were obtained in high yields. Georg Thieme Verlag Stuttgart · New York.
- Fu, Ying,Hu, Xuemei,Chen, Yaojuan,Yang, Yanshou,Hou, Hongxia,Hu, Yulai
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experimental part
p. 1030 - 1036
(2012/05/04)
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- Radical-scavenging activity and mechanism of resveratrol-oriented analogues: Influence of the solvent, radical, and substitution
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(Chemical Equation Presented). Resveratrol (3,5,4′-trihydroxy-trans- stilbene, 3,5,4′-THS) is a well-known natural antioxidant and cancer chemopreventive agent that has attracted much interest in the past decade. To find a more active antioxidant and investigate the antioxidative mechanism with resveratrol as the lead compound, we synthesized 3,5-dihydroxy-trans-stilbene (3,5-DHS), 4-hydroxy-trans-stilbene (4-HS) 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4′-dihydroxy-trans-stilbene (4,4′-DHS), 4-hydroxy-3-methoxy-trans-stilbene (3-MeO-4-HS), 4-hydroxy-4′-methoxy- trans-stilbene (4′-MeO-4-HS), 4-hydroxy-4′-methyl-trans-stilbene (4′-Me-4-HS), 4-hydroxy-4′-nitro-trans-stilbene (4′-NO 2-4-HS), and 4-hydroxy-4′-trifluoromethyl-trans-stilbene (4′-CF3-4-HS). The radical-scavenging activity and detailed mechanism of resveratrol and its analogues (ArOHs) were investigated by the reaction kinetics with galvinoxyl (GO?) and 2,2-diphenyl-1- picrylhydrazyl (DPPH?) radicals in ethanol and ethyl acetate at 25°C, using UV-vis spectroscopy. It was found that the reaction rates increase with increasing the electron-rich environment in the molecules, and the compound bearing o-dihydroxyl groups (3,4-DHS) is the most reactive one among the examined resveratrol analogues. The effect of added acetic acid on the measured rate constant for GO?-scavenging reaction reveals that in ethanol that supports ionization solvent besides hydrogen atom transfer (HAT), the kinetics of the process is partially governed by sequential proton loss electron transfer (SPLET). In contrast to GO?, DPPH ? has a relatively high reduction potential and therefore enhances the proportion of SPLET in ethanol. The relatively low rate constants for the reactions of ArOHs with GO? or DPPH? in ethyl acetate compared with the rate constants in ethanol prove that in ethyl acetate these reactions occur primarily by the HAT mechanism. The contribution of SPLET and HAT mechanism depends on the ability of the solvent to ionize ArOH and the reduction potential of the free radical involved. Furthermore, the fate of the ArOH-derived radicals, i.e., the phenoxyl radicals, was investigated by the oxidative product analysis of ArOHs and GO? in ethanol. The major products were dihydrofuran dimers in the case of resveratrol, 4,4′-DHS, and 4-HS and a dioxane-like dimer in the case of 3,4-DHS. It is suggested from the oxidative products of these ArOHs that the hydroxyl group at the 4-position is much easier to subject to oxidation than other hydroxyl groups, and the dioxane-like dimer is formed via an o-quinone intermediate.
- Shang, Ya-Jing,Qian, Yi-Ping,Liu, Xiao-Da,Dai, Fang,Shang, Xian-Ling,Jia, Wen-Qiang,Liu, Qiang,Fang, Jian-Guo,Zhou, Bo
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supporting information; experimental part
p. 5025 - 5031
(2009/10/17)
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- An unusual, mild and convenient one-pot two-step access to (E)-stilbenes from hydroxy-substituted benzaldehydes and phenylacetic acids under microwave activation: a new facet of the classical Perkin reaction
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A mild and convenient one-pot two-step synthesis of hydroxystilbenes with trans selectivity has been developed through a modified Perkin reaction between benzaldehydes and phenylacetic acids bearing 4- or 2-hydroxy substitution at the aromatic ring, in the presence of piperidine-methylimidazole and polyethylene glycol under microwave irradiation. The observation of a simultaneous condensation-decarboxylation leading to the unusual formation of hydroxystilbenes in lieu of α-phenylcinnamic acid reveals an interesting facet to the classical Perkin reaction. The developed protocol provides a green alternative to the prevalent methods employing a toxic decarboxylating agent in the form of quinoline/Cu salt, and the requirement for harsh protection-deprotection steps for the synthesis of hydroxylated stilbenes.
- Sinha, Arun K.,Kumar, Vinod,Sharma, Abhishek,Sharma, Anuj,Kumar, Rakesh
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p. 11070 - 11077
(2008/02/12)
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- Original one-pot microwave-promoted Hunsdiecker-Suzuki strategy: straightforward access to trans-1,2-diarylethenes from cinnamic acids
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An original strategy combining a Hunsdiecker-type bromodecarboxylation and a Suzuki cross-coupling reaction starting from various cinnamic acids has been developed in one-pot and under microwave heating to give trans-1,2-diarylethenes in few minutes.
- Bazin, Marc-Antoine,Kihel, La?la El,Lancelot, Jean-Charles,Rault, Sylvain
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p. 4347 - 4351
(2008/02/04)
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- Remarkable synergism in methylimidazole-promoted decarboxylation of substituted cinnamic acid derivatives in basic water medium under microwave irradiation: a clean synthesis of hydroxylated (E)-stilbenes
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A metal-free protocol for decarboxylation of substituted α-phenylcinnamic acid derivatives in aqueous media is developed, wherein a remarkable synergism between methylimidazole and aq NaHCO3 in polyethylene glycol under microwave furnished the corresponding para/ortho hydroxylated (E)-stilbenes in a mild and efficient manner. The critical role of water in facilitating the decarboxylation imparts an interesting facet to the synthetic utility of water mediated organic transformations. The developed protocol provides a clean alternative to the hitherto indispensable multistep approaches involving toxic quinoline and a copper salt combination as the common decarboxylating agent.
- Kumar, Vinod,Sharma, Abhishek,Sharma, Anuj,Sinha, Arun K.
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p. 7640 - 7646
(2008/02/09)
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- Substituted CIS- and trans-stilbenes as therapeutic agents
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The present invention relates to method(s) of treating a subject afflicted with cancer or a precancerous condition, an inflammatory disease or condition, and/or stroke or other ischemic disease or condition, the method comprising administering to the subject or patient in need a composition comprising a therapeutically effective amount of a substituted cis or trans-stilbene.
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Page/Page column 21
(2010/11/28)
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- Substituted trans-stilbenes, including analogues of the natural product resveratrol, inhibit the human tumor necrosis factor alpha-induced activation of transcription factor nuclear factor kappaB
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The transcription factor nuclear factor kappaB (NF-κB), which regulates expression of numerous antiinflammatory genes as well as genes that promote development of the prosurvival, antiapoptotic state is up-regulated in many cancer cells. The natural product resveratrol, a polyphenolic trans-stilbene, has numerous biological activities and is a known inhibitor of activation of NF-κB, which may account for some of its biological activities. Resveratrol exhibits activity against a wide variety of cancer cells and has demonstrated activity as a cancer chemopreventive against all stages, i.e., initiation, promotion, and progression. The biological activities of resveratrol are often ascribed to its antioxidant activity. Both antioxidant activity and biological activities of analogues of resveratrol depend upon the number and location of the hydroxy groups. In the present study, phenolic analogues of resveratrol and a series of substituted trans-stilbenes without hydroxy groups were compared with resveratrol for their abilities to inhibit the human tumor necrosis factor alpha-induced (TNF-α) activation of NF-κB, using the Panomics NF-κB stable reporter cell line 293/NF-κB-luc. A series of 75 compounds was screened to identify substituted trans-stilbenes that were more active than resveratrol. Dose-response studies of the most active compounds were carried out to obtain IC50 values. Numerous compounds were identified that were more active than resveratrol, including compounds that were devoid of hydroxy groups and were 100-fold more potent than resveratrol. The substituted trans-stilbenes that were potent inhibitors of the activation of NFκB generally did not exhibit antioxidant activity. The results from screening were confirmed using BV-2 microglial cells where resveratrol and analogues were shown to inhibit LPS-induced COX-2 expression.
- Heynekamp, Justin J.,Weber, Waylon M.,Hunsaker, Lucy A.,Gonzales, Amanda M.,Orlando, Robert A.,Deck, Lorraine M.,Vander Jagt, David L.
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p. 7182 - 7189
(2007/10/03)
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- Synthesis and anti-implantation activity of new stilbene derivatives
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New stilbene (CAS 56-53-1) derivatives have been synthesized by reductive elimination of desosybenzoin analogs which were obtained by Fries rearrangement of the corresponding phenolic esters. The chemical structures of the compounds obtained were confirmed by 1H-NMR, IR and elemental analysis. Anti-implantation activity of the compounds was determined by performing experiments with adult male and female Spargue-Dawley rats of proven fertility. A 67 % inhibition of implantation was observed separately with compounds 3f and 3i.
- Bandichhor, Rakeshwar,Singh, Kunwar A.,Nosse, Bernd,Tandon, Vishnu K.
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p. 452 - 455
(2007/10/03)
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- A convenient one-pot completely stereoselective synthesis of trans-4-Hydroxystilbenes and its derivatives and X-ray structure of its precursor
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The synthesis of E-isomer of 4-Hydroxystilbene and its derivatives 3 by reductive elimination of the carbonyl function in 2-phenyl-1-(4-hydroxyphenyl)ethan-1-one and its derivatives 2 and the X-ray structure of 2a are described.
- Chhor, Rakeshwar B.,Singh, Kunwar A.,Nosse,Tandon, Vishnu K.
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p. 2519 - 2530
(2007/10/03)
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