- Antioxidant properties of two novel lipophilic derivatives of hydroxytyrosol
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Two novel lipophilic derivatives of the natural olive oil phenol, hydroxytyrosol (HT), were synthesized using 3,4-dihydroxyphenylacetic acid as starting material. Their antioxidant activities and kinetics compared to HT and TBHQ were assessed by Rancimat,
- Olajide, Tosin M.,Liu, Tao,Liu, Haian,Weng, Xinchu
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Read Online
- Synthesis of Forsythenethoside A, a Neuroprotective Macrocyclic Phenylethanoid Glycoside, and NMR Analysis of Conformers
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Forsythenethoside A (1) is a structurally unique macrocyclic phenylethanoid glycoside, which was isolated from Forsynthia suspensa and displayed considerable neuroprotective activities. Here, we report its first chemical synthesis via a longest linear sequence of 14 steps in 5% overall yield wherein intramolecular oxidative coupling was successfully employed to realize the pivotal macrocyclization. NMR analysis revealed the existence of an unexpected conformational interconversion of the congested macrocycles.
- Hu, Zhifei,Silipo, Alba,Li, Wei,Molinaro, Antonio,Yu, Biao
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- Flavonoids, flavonoid metabolites, and phenolic acids inhibit oxidative stress in the neuronal cell line HT-22 monitored by ECIS and MTT assay: A comparative study
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A real-time and label-free in vitro assay based on electric cell-substrate impedance sensing (ECIS) was established, validated, and compared to an end-point MTT assay within an experimental trial addressing the cytoprotective effects of 19 different flavo
- Kling, Beata,Bücherl, Daniel,Palatzky, Peter,Matysik, Frank-Michael,Decker, Michael,Wegener, Joachim,Heilmann, J?rg
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Read Online
- Bioorthogonal Ligation and Cleavage by Reactions of Chloroquinoxalines with ortho-Dithiophenols
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A bioorthogonal ligation and cleavage method via reactions of chloroquinoxalines (CQ) and ortho-dithiophenols (DT) is presented. Double nucleophilic substitutions of ortho-dithiophenols to chloroquinoxalines provide conjugates containing tetracyclic benzo[5,6][1,4]dithiino[2,3-b]quinoxaline with strong built-in fluorescence together with release of the other functional molecules. Three cleavable linkers were designed and successfully used in release of the molecules containing biotin from the protein conjugates. The CQ-DT bioorthogonal reactions can be applied for the bioorthogonal ligations, bioorthogonal cleavages, and trans-tagging of proteins, and show advantages of readily accessible unnatural orthogonal groups, appealing reaction kinetics (k2≈1.3 m?1 s?1), excellent biocompatibility of orthogonal groups, and high stability of conjugates. This complements previous bioorthogonal reactions and is a new route for protein-fishing applications and in-gel fluorescence analysis.
- Fu, Hua,Li, Hongyun,Li, Youshan,Lou, Zhenbang,Yang, Haijun,Zhao, Yufen
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supporting information
p. 3671 - 3677
(2020/02/04)
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- Regioselectivity of Cobalamin-Dependent Methyltransferase Can Be Tuned by Reaction Conditions and Substrate
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Regioselective reactions represent a significant challenge for organic chemistry. Here the regioselective methylation of a single hydroxy group of 4-substituted catechols was investigated employing the cobalamin-dependent methyltransferase from Desulfitobacterium hafniense. Catechols substituted in position four were methylated either in meta- or para-position to the substituent depending whether the substituent was polar or apolar. While the biocatalytic cobalamin dependent methylation was meta-selective with 4-substituted catechols bearing hydrophilic groups, it was para-selective for hydrophobic substituents. Furthermore, the presence of water miscible co-solvents had a clear improving influence, whereby THF turned out to enable the formation of a single regioisomer in selected cases. Finally, it was found that also the pH led to an enhancement of regioselectivity for the cases investigated.
- Pompei, Simona,Grimm, Christopher,Farnberger, Judith E.,Schober, Lukas,Kroutil, Wolfgang
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p. 5977 - 5983
(2020/10/06)
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- Structure–Activity Relationship of Anti-malarial Allylpyrocatechol Isolated from Piper betle
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Malaria disease remains a serious worldwide health problem. In South-East Asia, one of the malaria infection “hot-spots,” medicinal plants such as Piper betle have traditionally been used for the treatment of malaria, and allylpyrocatechol (1), a constituent of P. betle, has been shown to exhibit anti-malarial activities. In this study, we verified that 1 showed in vivo anti-malarial activity through not only intraperitoneal (i.p.) but also peroral (p.o.) administration. Additionally, some analogs of 1 were synthesized and the structure–activity relationship was analyzed to disclose the crucial sub-structures for the potent activity.
- Horii, Toshihiro,Itagaki, Sawako,Kawano, Tomikazu,Miyoshi, Akihito,Murakami, Nobutoshi,Tamura, Satoru
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p. 784 - 790
(2020/09/18)
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- Synthesis and antioxidant activity of conjugates of hydroxytyrosol and coumarin
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Antioxidants have been the subject of intense research interest due to their numerous health benefits. In this work, a series of new conjugates of hydroxytyrosol and coumarin were synthesized and evaluated for their free radical scavenging, toxicity and antioxidant mechanism in vitro. The all target compounds 14a–t exhibited better radical scavenging activity than BHT, hydroxytyrosol, and coumarin in both DPPH radical and ABTS+ radical cation scavenging assays. The structure-activity relationships study indicated that the number and position of hydroxyl groups on the coumarin ring were vital to a good antioxidant capacity. Furthermore, the most promising compound 14q showed less toxicity in hemolysis assay and weaker antiproliferative effects than BHT against normal WI-38 and GES cells, and enhanced viability of H2O2-induced HepG2 cells. Additionally, 14q decreased the apoptotic percentage of HepG2 cells, reduced the ROS produce and LDH release, and improved GSH and SOD levels in H2O2-treated HepG2 cells. Lastly, 14q exhibited more stability than hydroxytyrosol in methanol solution. These results revealed that conjugations of hydroxytyrosol and coumarin show better antioxidant capacity, and are the efficacious approach to finding novel potential antioxidant.
- Li, Wen-Bo,Qiao, Xue-Peng,Wang, Zi-Xiao,Wang, Shuai,Chen, Shi-Wu
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- Preparation method of hydroxytyrosol
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The invention relates to the technical field of medicinal chemical synthesis, in particular to a preparation method of hydroxytyrosol. The preparation method of the hydroxytyrosol comprises the following step of taking an alcohol and/or an ether as a solvent to carry out a reaction on methyl 3,4-dihydroxyphenylacetate under the action of a reducing agent and Lewis acid to obtain the hydroxytyrosol. According to the preparation method of the hydroxytyrosol, the reducing agent and the Lewis acid are matched for carrying out catalytic reducing, so that reaction activity is improved, and the product yield and purity are high. In addition, the single solvent is used, so that post-treatment is convenient, the solvent is convenient to recycle, energy consumption and material loss are reduced, andproduction cost is greatly saved.
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- BIOISPIRED PROTEASOME ACTIVATORS WITH ANTIAGEING ACTIVITY
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The present invention relates to novel bio-inspired hybrid compounds of formula I which act as proteasome activators and exhibit anti-ageing activity, as well as methods for their synthesis. These hybrid compounds combine the structural features of hydroxytyrosol and the natural antioxidant vitamin E or its bioisosteres in one molecular scaffold. The compounds of formula I, which include structural proteasome activators (activation by stereochemical interaction), can be used in the production of anti-ageing products, such as cosmetic preparations. Additionally, they can be used in conditions and diseases where the proteasome is down-regulated, as well as proteasome-activation control compounds.
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- NHC catalyzed enantioselective Coates-Claisen rearrangement: A rapid access to the dihydropyran core for oleuropein based secoiridoids
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We present the short synthesis of the suitably functionalized enantioselective dihydropyran core of secoiridoids using an N-heterocyclic carbene (NHC) catalyzed Coates-Claisen rearrangement mechanism. The key steps of the synthesis are (i) the highly enantioselective NHC catalyzed Coates-Claisen rearrangement for the dihydropyran core, (ii) the assembly of the target dihydropyran core structure of oleuropein from a highly diastereoselective exocyclic trans alkene, and (iii) the highly stereoselective assembly of a monoterpene elenolide core structure.
- Vedachalam, Seenuvasan,Murugesh, Nithya,Chakraborty, Priyanka,Karvembu, Ramasamy,Liu, Xue-Wei
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supporting information
p. 1832 - 1839
(2018/02/09)
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- METHOD FOR PREPARATION OF HYDROXYTYROSOL
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The invention discloses a method for the preparation of (3,4-dihydroxyphenyl)acetic acid or its ester starting from the respective nitrile, and the conversion of (3,4-dihydroxyphenyl)acetic acid ester to hydroxytyrosol.
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Page/Page column 9
(2017/09/15)
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- Diversity Oriented Synthesis of Allocolchicinoids with Fluoro and/or Oxygen Substituent(s) on the C-Ring from a Single Common Intermediate
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Allocolchicinoids, with a distinct polyoxygenated dibenzocycloheptane skeleton, attract much attention as potential candidate anticancer drugs. In this study, eight C-ring fluorinated analogues of allocolchicinoids, seven C-ring oxygen-substituted analogu
- Takubo, Keita,Furutsu, Kazunori,Ide, Takafumi,Nemoto, Hiroyuki,Ueda, Yuko,Tsujikawa, Kazutake,Ikawa, Takashi,Yoshimitsu, Takehiko,Akai, Shuji
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supporting information
p. 1562 - 1576
(2016/04/05)
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- Catechol-based substrates of chalcone synthase as a scaffold for novel inhibitors of PqsD
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A new strategy for treating Pseudomonas aeruginosa infections could be disrupting the Pseudomonas Quinolone Signal (PQS) quorum sensing (QS) system. The goal is to impair communication among the cells and, hence, reduce the expression of virulence factors and the formation of biofilms. PqsD is an essential enzyme for the synthesis of PQS and shares some features with chalcone synthase (CHS2), an enzyme expressed in Medicago sativa. Both proteins are quite similar concerning the size of the active site, the catalytic residues and the electrostatic surface potential at the entrance of the substrate tunnel. Hence, we evaluated selected substrates of the vegetable enzyme as potential inhibitors of the bacterial protein. This similarity-guided approach led to the identification of a new class of PqsD inhibitors having a catechol structure as an essential feature for activity, a saturated linker with two or more carbons and an ester moiety bearing bulky substituents. The developed compounds showed PqsD inhibition with IC50 values in the single-digit micromolar range. The binding mode of these compounds was investigated by Surface Plasmon Resonance (SPR) experiments revealing that their interaction with the protein is not influenced by the presence of the anthranilic acid bound to active site cysteine. Importantly, some compounds reduced the signal molecule production in cellulo.
- Allegretta, Giuseppe,Weidel, Elisabeth,Empting, Martin,Hartmann, Rolf W.
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p. 351 - 359
(2015/02/19)
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- Compositions and methods for treating obesity, obesity related disorders and for inhibiting the infectivity of human immunodeficiency virus
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The present invention relates to methods and pharmaceutical compositions for treating obesity or obesity-related disorders in a subject suffering from or predisposed to developing obesity or an obesity-related disorder, or for inhibiting the infectivity of HIV, by administering oleuropein, an analogue or derivative thereof, or the major metabolites of oleuropein including oleuropein aglycone, hydroxytyrosol, and elenolic acid or their analogues, or derivatives thereof, an iridoid glycoside, or a secoiridoid glycoside or analogues or derivatives thereof, or any combination of the foregoing including olive leave extract. The invention also relates to methods for screening/diagnosing a subject having, or predisposed to having obesity or a related disorder by measuring the expression profiles of an adipogenic gene selected from PPARγ2, LPL and αP2 gene and gene product, or other adipogenic, lipogenic, or lipolytic genes and gene products in an individual. The invention further provides for screening for novel oleuropein analogues.
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Page/Page column 66
(2015/10/28)
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- NOVEL DERIVATIVES OF SINAPINIC ACID AND THE COSMETIC OR PHARMACEUTICAL USES THEREOF
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The present invention relates to a compound of general formula (I) below: in which: R1, R2 and R3 independently of one another represent a hydrogen atom; a C1-12 alkyl group; a C2-12 alkenyl group; a C2-12 alkynyl group; a C3-12 cycloalkyl group; a C1-12 acyl group; a sulfonyl group or a phosphonate group; represents a CH2—CH2 group or a CH═CH group; n is an integer between 1 and 3; or a salt thereof. The invention further relates to a process for synthesizing this compound or salt, to a composition comprising it, to its cosmetic use, more particularly as a depigmenting agent and/or as a radical scavenger, to a cosmetic care process, and to its use as a drug, advantageously intended for preventing and/or treating pathological hyperpigmentation and/or inflammation.
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Paragraph 0170-0171
(2015/12/23)
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- Design, synthesis and biological evaluation of small molecular polyphenols as entry inhibitors against H5N1
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To find novel compounds against H5N1, three series of known or novel small molecular polyphenols were synthesized and tested in vitro for anti-H5N1 activity. In addition, the preliminary structure-antiviral activity relationships were elaborated. The results showed that some small molecular polyphenols had better anti-H5N1 activity, and could serve as novel virus entry inhibitors against H 5N1, likely targeting to HA2 protein. Noticeably, compound 4a showed the strongest activity against H5N1 among these compounds, and the molecular modeling analysis also suggested that this compound might target to HA2 protein. Therefore, compound 4a is well qualified to serve as a lead compound or scaffold for the further development of H 5N1 entry inhibitor.
- Yang, Jian,Yang, Jing Xiang,Zhang, Fang,Chen, Gang,Pan, Wei,Yu, Rui,Wu, Shuwen,Tien, Po
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p. 2680 - 2684
(2014/06/09)
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- Tyrosinase and Layer-by-Layer supported tyrosinases in the synthesis of lipophilic catechols with antiinfluenza activity
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Catechol derivatives with lipophilic properties have been selectively synthesized by tyrosinase in high yield avoiding long and tedious protection/deprotection steps usually required in traditional procedures. The synthesis was effective also with immobilized tyrosinase able to perform for more runs. The novel catechols were evaluated against influenza A virus, that continue to represent a severe threat worldwide. A significant antiviral activity was observed in derivatives characterized by antioxidant activity and long carbon alkyl side-chains, suggesting the possibility of a new inhibition mechanism based on both redox and lipophilic properties.
- Bozzini, Tiziana,Botta, Giorgia,Delfino, Michela,Onofri, Silvano,Saladino, Raffaele,Amatore, Donatella,Sgarbanti, Rossella,Nencioni, Lucia,Palamara, Anna Teresa
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p. 7699 - 7708
(2014/01/06)
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- Bifunctional catechol based linkers for modification of TiO2 surfaces
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Bifunctional linkers for modification of TiO2 nanoparticles were prepared containing a catechol group for TiO2 surface attachment and a maleimide and alkyne group for Michael addition and Cu catalysed Huisgen cycloaddition respectively. Peptide and fluorophore functionalised TiO 2 NPs were prepared, different purification methodologies were explored and conjugates were characterized using a range of methods.
- Geiseler, Bianca,Fruk, Ljiljana
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experimental part
p. 735 - 741
(2012/04/04)
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- Synthesis and biological evaluation of caffeic acid 3,4-dihydroxyphenethyl ester
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A high-yield synthesis of caffeic acid 3,4-dihydroxyphenethyl ester (1) has been achieved through Knoevenagel condensation of 3,4-dihydroxybenzaldehyde and 3,4-dihydroxyphenethyl monomalonate as the key step. Compound 1 was tested against a 56-cell-line cytotoxicity panel and for its free-radical-scavenging activity in the DPPH test.
- Zhang, Zhizhen,Xiao, Binghua,Chen, Qi,Lian, Xiao-Yuan
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experimental part
p. 252 - 254
(2010/07/08)
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- Boronate derivatives of functionally diverse catechols: Stability studies
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Benzeneboronate of catecholic carboxyl methyl esters, N-acetyldopamine, coumarin and catechol estrogens were prepared as crystalline derivatives in high yield. Related catechol compounds with extra polar functional group(s) (OH, NH2) do not for
- Ketuly, Kamal Aziz,Hadi, A. Hamid A.
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experimental part
p. 2347 - 2356
(2010/08/04)
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- Self-assembly of hybrid dendrons into doubly segregated supramolecular polyhedral columns and vesicles
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The synthesis and structural analysis of supramolecular dendrimers self-assembled from 3 libraries containing 20 first-generation hybrid dendrons are reported. Combinations of benzyl ether, naphthyl methyl ether, and biphenyl methyl ether repeat units wit
- Peterca, Mihai,Imam, Mohammad R.,Leowanawat, Pawaret,Rosen, Brad M.,Wilson, Daniela A.,Wilson, Christopher J.,Zeng, Xiangbing,Ungar, Goran,Heiney, Paul A.,Percec, Virgil
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supporting information; experimental part
p. 11288 - 11305
(2010/10/04)
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- DEUTERATED ZAMIFENACIN DERIVATIVES
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Disclosed herein are substituted piperidine-based muscarinic receptor modulators of Formula (I), process of preparation thereof, pharmaceutical compositions thereof, and methods of use thereof. At least one of the R groups is a deuterium atom.
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Page/Page column 63-64; 66; 68; 70; 73
(2009/01/20)
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- Use of hydroxytyrosol for the treatment of cartilage injury
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The invention relates to the use of hydroxytyrosol for inducing or enhancing cartilage repair or cartilage regeneration. Furthermore, the invention relates to nutraceutical and pharmaceutical compositions comprising hydroxytyrosol for regeneration and repair of cartilage injuries in joints, in particular of traumatic cartilage injuries.
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Page/Page column 11-12
(2008/12/04)
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- PROCESS FOR THE PREPARATION OF PHENOLIC COMPOUNDS
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Process for the preparation of hydroxytyrosol and its precursors (3,4- dihydroxyphenyl)-acetic acid C1-10-alkyl esters by hydrogenating in a C1-10-alkanol 3,4- mandelic acid or a 3,4-dihydroxymandelic acid C1-10-alkyl ester in the presence of a hydrogenation metal catalyst and optionally reducing the ester obtained to give hydroxytyrosol.
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Page/Page column 9
(2010/11/25)
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- High-yielding preparation of a stable precursor of hydroxytyrosol by total synthesis and from the natural glycoside oleuropein
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The unprecedented acetonide of the antioxidant hydroxytyrosol has been synthesized by a two-step high-yielding procedure and found to be both purifiable by chromatography and stable over a wide pH range. The protection stabilizes hydroxytyrosol against oxidation, thereby allowing long-term storage. The protection can quantitatively be removed, under nonaqueous conditions, to afford pure hydroxytyrosol suitable for use as an additive in food and cosmetic preparations. Extension of the same methodology to the natural and easily accessible glycoside oleuropein, followed by saponification of the resulting complex mixture of acetonides, allowed hydroxytyrosol acetonide to be recovered in high yield. This constitutes a new interesting methodology to obtain the antioxidant hydroxytyrosol.
- Gambacorta, Augusto,Tofani, Daniela,Bernini, Roberta,Migliorini, Antonella
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p. 3386 - 3391
(2008/02/07)
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- DITHIAZOLE COMPOUNDS, MATRIX METALLOPROTEASE INHIBITORS AND EXTERNAL PREPARATIONS FOR THE SKIN
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A dithiazole compound or a salt thereof expressed by formula (I): wherein R1, is hydrogen atom, alkyl, etc.; R2 is hydrogen atom, hydroxy, alkyl, aryl, arylalkoxy, arylalkyl, etc.; R3 is one group of formulae (II), (III) and (IV): This compound has an excellent inhibiting action on matrix metalloprotease (MMPs) activity, and is useful for pharmaceutical, cosmetic and skin external compositions.
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- Convenient syntheses of biogenic aldehydes, 3,4-dihydroxyphenylacetaldehyde and 3,4-dihydroxyphenylglycolaldehyde
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The title compounds were prepared from a common precursor, a bis-THP-protected dihydroxyphenylacetic acid methyl ester. Key steps are the introduction of the α-hydroxyl group by Davis oxaziridine reagent and formation of the aldehydes by DIBALH ester reduction.
- Narayanan, Jayan,Hayakawa, Yoshio,Fan, Junfa,Kirk, Kenneth L.
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p. 191 - 197
(2007/10/03)
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- Differential inhibition of polymerase and strand-transfer activities of HIV-1 reverse transcriptase
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A new class of inhibitors of HIV-1 reverse transcriptase obtained by the systematic structural simplification of epicatechin and epigallocatechin gallates are also shown here to inhibit DNA-strand-transfer, a process critical to the completion of the HIV-1-RT reproduction and to recombination-associated mutation of the virus. Up to 80-fold selectivity for DNA-strand-transfer inhibition over polymerase inhibition was observed for a defined subset of these agents. Such specific DNA-strand-transfer inhibitors may have important therapeutic potential.
- Tillekeratne,Sherette, Angela,Fulmer, Jennifer A,Hupe, Lynn,Hupe, Donald,Gabbara, Sam,Peliska, James A,Hudson, Richard A
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p. 525 - 528
(2007/10/03)
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- Enantioselective syntheses of dopaminergic (R)- and (S)-benzyltetrahydroisoquinolines
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Optically pure (1S,R)- and (1R,S)-benzyltetrahydroisoquinolines (BTHIQs), 12a,b as the major diastereomers, were prepared by stereoselective reduction of the isoquinolinium salt possessing (R)- and (S)-phenylglycinol as the chiral auxiliary, respectively. The absolute configurations of (1S,R)-13a hydrochloride (O-debenzoylated derivative from 12a) and (1R,S)-12b diastereomers were unambiguously determined by single-crystal X-ray analysis. Reductive removal of the chiral auxiliary group, subsequent N-propylation, and cleavage of the methylenedioxy group furnished the optically active catecholamines (1S)-16a and (1R)-16b in good overall yield. We have separately prepared for the first time pairs of dopaminergic 1-BTHIQs enantiomers through a classical methodology in asymmetric synthesis. The (1S)-enantiomers (14a-16a) bind to D1 and D2 dopamine receptors with affinities 5-15 times higher than those of the corresponding (IR)-enantiomers (14b-16b). Moreover, (1S)-14a inhibits [3H]dopamine uptake with high affinity. It appears that synthesis and testing of (S)-enantiomers of BTHIQ are very important for the search for new active drugs at dopamine receptors.
- Cabedo,Andreu,Ramirez de Arellano,Chagraoui,Serrano,Bermejo,Protais,Cortes
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p. 1794 - 1801
(2007/10/03)
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- Simplified catechin-gallate inhibitors of HIV-1 reverse transcriptase
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Systematic simplification of the molecular structures of epicatechin gallate and epigallocatechin gallate to determine the minimum structural characteristics necessary for HIV-1 reverse transcriptase inhibition in vitro resulted in several compounds that strongly inhibited the native as well as the A17 double mutant (K103N Y181C) enzyme, which is normally insensitive to most known nonnucleoside inhibitors.
- Tillekeratne,Sherette,Grossman,Hupe,Hupe,Hudson
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p. 2763 - 2767
(2007/10/03)
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- Indole derivatives as steroid 5α-reductase inhibitors
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A method of treatment of a human to inhibit a steroid 5α-reductase, particularly a testosterone 5α-reductase, which comprises treating said human with an effective amount of a compound of the formula (I) STR1 or a pharmaceutically acceptable base salt the
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- Preparation of primary amines by the alkylation of O-sulfonyloximes of benzophenone derivatives with Grignard reagents
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Primary amines are prepared by the electrophilic amination of Grignard reagents with benzophenone O-sulfonyloxime derivatives. 4,4'- Bis(trifluoromethyl)benzophenone O-sulfonyloximes react with alkyl Grignard reagents in the presence of a catalytic amount of CuCN in tetrahydrofuran- hexamethylphosphoric triamide to give N-alkylimines, which are readily hydrolyzed to primary amines. 3,3',5,5'-Tetrakis(trifluoromethyl)benzophenone O-p-tolylsulfonyloxime is arylated to the corresponding N-arylimines with aryl Grignard reagents in ether-toluene, and hydrolysis of the resulting imines gives aniline derivatives.
- Tsutsui, Hironori,Ichikawa, Tomoko,Narasaka, Koichi
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p. 1869 - 1878
(2007/10/03)
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- Synthesis of verbascoside: A dihydroxyphenylethyl glycoside with diverse bioactivity
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TMSOTf-mediated condensation of ethyl 4,6-O-benzylidene-1-thio-β-D- glucopyranoside (2) with peracetylated α-L-rhamnopyranosyl trichloroacetimidate donor 3a resulted in the formation of orthoester 4, which, after acetylation, rearranged into ethyl 3-O-(α-L-rhamnopyranosyl)-l- thio-β-D-glucopyranoside derivative 6a. The latter compound was converted into the corresponding trichloroacetimidate donors 8a-b. An alternative approach to trichloroacetimidate 8c commenced with the iodonium ion mediated glycosidation of ethyl 2,3,4-tri-O-benzoyl-1-thio-α-L-rhamnopyranside (15) with 1,2:5,6-diisopropylidene-D-glucofuranose (16) to afford disaccharide 17, which was transformed into 8c in five steps. Condensation of 8a-c with 2- [3,4-di-(tert-butyldimethylsilyloxy)phenyl]ethanol (12) gave, after deacylation, key intermediate 14. Protecting-group manipulation of 14 and subsequent esterification of resulting 22 with 3,4-di-O-tert- butyldimethylsilylcaffeic acid (27) gave, after deprotection, verbascoside (1).
- Duynstee, Howard I.,De Koning, Martijn C.,Ovaa, Huib,Van Der Marel, Gijs A.,Van Boom, Jacques H.
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p. 2623 - 2632
(2007/10/03)
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- Preparation and catalytic properties of resin bound binuclear rhodium tetracarboxylate complexes
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4-(4'-Polystyryimethyloxy)-3-carboxylatomethyloxy-1-phenylacetate bis- μ-coordinated rhodium(II) diacetate complex, a resin-bound analogue of dirhodium tetraacetate in which two adjacent μ-bridging acetate moleties are covalently linked, serves as an efficient, stable and re-useable immobilised alkene hydrofomylation and hydrogenation catalyst.
- Andersen, Jo-Ann M.,Karodia, Nazira,Miller, David J.,Stones, Duane,Gani, David
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p. 7815 - 7818
(2007/10/03)
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- Indole derivatives as steroid 5α-reductase inhibitors
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Compounds of formula (I) STR1 and the pharmaceutically acceptable base salts thereof, wherein R is --CO2 H or tetrazol-5 yl; R1 is C3 -C8 alkyl optionally substituted by fluoro; and R2 is C2/sub
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- ANTIOXIDATIVE ACTIVITES OF OLEA EUROPAEA LEAVES AND RELATED PHENOLIC COMPOUNDS
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Olea europaea leaves, oleuropein, hydroxytyrosol and tyrosol were compared with vitamin E and BHT, with regard to their antioxidative activities, by kinetic studies in model systems.The thermal initiated oxidation of methyl linoleate was performed on homogeneous solution at 60 deg or 40 deg with or without antioxidants.Olea europaea extracts, oleuropein and hydroxytyrosol were much more effective than BHT or vitamin E in extending the induction period.Assuming a stoichiometric factor f=2 for BHT, this coefficient of inhibition reached 5 for hydroxytyrosol, 7 for oleuropein and 10 for O. europaea extracts.These extracts owe their antioxidative properties to their high oleuropein content (19percent w/w) and also to a lesser amount of flavonoids (1.8percent w/w with 0.8percent of luteolin 7-glucoside).Tyrosol showed neither antioxidant nor prooxidant activity.No synergistic effect on the preservation of methyl linoleate was found when vitamin E was used together with tyrosol or O. europaea extracts. Key Word Index - Olea europaea; Oleaceae; olive tree; leaves, oleuropein; hydroxytyrosol; tyrosol; flavonoids; antioxidant; BHT, vitamin E; tocopherol; methyl linoleate.
- Tutour, Bernard Le,Guedon, Didier
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p. 1173 - 1178
(2007/10/02)
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- IRIDOID AND PHENOLIC GLYCOSIDES FROM HARPAGOPHYTUM PROCUMBENS
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Key Word Index - Harpagophytum procumbens; Pedaliaceae; iridoid and phenolic glycosides; synthesis.A novel bioside, β-(3',4'-dihydroxyphenyl)ethyl-O-α-L-rhamnopyranosyl(1 -> 3)-β-D-glucopyranoside, was obtained from the secondary roots of Harpagophytum procumbens.It is accompained by the known iridoid glucosides harpagoside, procumbide, and its 6'-O-p-coumaroyl ester, and phenolic glycosides, acteoside and isoacteoside, the latter pair being obtained from H. procumbens for the first time.The structures of these metabolites were differentiated by high resolution NMR studies, while that of the bioside is additionally supported by synthesis.
- Burger, Johann F. W.,Brandt, E. Vincent,Ferreira, Daneel
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p. 1453 - 1458
(2007/10/02)
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