- Chemoselective and efficient carbomethoxylation of the alcoholic chain of phenols by dimethyl carbonate (DMC)
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The efficiency of dimethyl carbonate (DMC) as chemoselective carbomethoxylating agent of the alcoholic chain of phenols has been investigated. In the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or sulfuric acid as catalysts, new carbomethoxylated
- Bernini, Roberta,Mincione, Enrico,Crisante, Fernanda,Barontini, Maurizio,Fabrizi, Giancarlo,Gentili, Patrizia
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- Synthesis and DPPH radical scavenging activity of novel compounds obtained from tyrosol and cinnamic acid derivatives
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Tyrosol, a naturally occurring phenolic compound poorly attractive as an antioxidant because of its weak efficacy, was used as starting material to obtain novel compounds. The synthesis is based on a trifluoroacetic acid-mediated hydroarylation of cinnamic esters with tyrosol to produce 4-aryl-3,4-dihydrocoumarins, molecules of biological interest, followed by a basic hydrolysis to give the corresponding ring opening products. Unreported mechanistic investigations confirmed that the first step resulted from an electrophilic aromatic substitution and an intramolecular transesterification. Final products exhibited DPPH radical scavenging activity significantly higher than tyrosol.
- Barontini, Maurizio,Bernini, Roberta,Carastro, Isabella,Gentili, Patrizia,Romani, Annalisa
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p. 809 - 816
(2014/02/14)
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- Easy eco-friendly phenonium ion production from phenethyl alcohols in dimethyl carbonate
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An efficient and simple one-pot procedure for selective etherification of 2-aryl-ethylalcohols has been achieved through Amberlyst 15-catalyzed reaction in dimethyl carbonate (DMC). Moreover, the polymer catalyst could be recovered and reused with no effect on its activity. The reaction mechanism involves the formation of phenonium ion which has been demonstrated by a C-C bond forming reaction. Theoretical studies are in agreement with and thus explain experimental results.
- Barontini,Proietti Silvestri,Nardi,Bovicelli,Pari,Gallucci,Spezia,Righi
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supporting information
p. 5004 - 5006
(2013/08/28)
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- Synthesis and biological evaluation of gallic acid analogs
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A novel and efficient synthesis of pyrogallol moiety through a copper(I)-mediated C-O bond forming reaction is described. In particular, syntheses of 3,4,5-trihydroxyphenethyl alcohol and its methyl derivative are reported. Particular attention to dimethy
- Barontini, Maurizio,Proietti Silvestri, Ilaria,Nardi, Valentina,Crisante, Fernanda,Pepe, Gaetano,Pari, Luigi,Gallucci, Francesco,Bovicelli, Paolo,Righi, Giuliana
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p. 674 - 680
(2013/04/10)
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- A singlet oxygen approach to oxaspirocycles
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A method for the preparation of oxygen containing spirocycles using singlet oxygen is reported. A series of phenols were converted into the corresponding peroxy-cyclohexadienone derivatives by irradiation with visible light in the presence of a sensitizer and oxygen. The resulting peroxides could be converted into ether and lactone spirocycles in one or two steps. The synthesis of the oxaspirocycles from the phenols can also be performed in a one-pot fashion, avoiding the isolation of the peroxide intermediates.
- Jones, Kevin M.,Hillringhaus, Tim,Klussmann, Martin
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supporting information
p. 3294 - 3297
(2013/06/27)
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- Synthesis of a novel ester of hydroxytyrosol and α-lipoic acid exhibiting an antiproliferative effect on human colon cancer HT-29 cells
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A novel ester of hydroxytyrosol and α-lipoic acid was synthesized in satisfactory yield by original and simple procedures and evaluated about its antiproliferative activity on the human colorectal adenocarcinoma HT-29 cell line. The compound exhibited a cell growth inhibitory activity significantly more potent than the corresponding parent natural compounds, very likely due to the induction of cell cycle arrest in the G2/M phase. These data suggest that the novel ester might exert a more effective antitumour activity than hydroxytyrosol and α-lipoic acid.
- Bernini, Roberta,Crisante, Fernanda,Merendino, Nicol,Molinari, Romina,Soldatelli, Maria Chiara,Velotti, Francesca
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experimental part
p. 439 - 446
(2011/02/25)
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- Convenient synthesis of hydroxytyrosol and its lipophilic derivatives from tyrosol or homovanillyl alcohol
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Hydroxytyrosol, a naturally occurred c-phenolic compound exhibiting antioxidant properties, was synthesized by a three-step high-yielding procedure from natural and low-cost compounds such as tyrosol or homovanillyl alcohol. First, the efficient chemoselective protection of the alcoholic group of these compounds was performed by using dimethyl carbonate (DMC) as reagent/solvent; second, the oxidation with 2-iodoxybenzoic acid (IBX) or Dess-Martin periodinane reagent (DMP) and in situ reduction with sodium dithionite (Na 2S2O4) allowed the preparation of carboxymethylated hydroxytyrosol; finally, by a mild hydrolytic step, hydroxytyrosol was obtained in high yield and purity, as confirmed by NMR spectra and HPLC profile. By using a similar methodology, lipophilic hydroxytyrosol derivatives, utilized as additives in pharmaceutical, food, and cosmetic preparations, were prepared. In fact, at first the chemoselective protection of the alcoholic group of tyrosol and homovanillyl alcohol was performed by using acyl chlorides without any catalyst to obtain the corresponding lipophilic derivatives, and then these compounds were converted in good yield and high purity into the hydroxytyrosol derivatives by oxidative/reductive pathway with IBX or DMP and Na2S 2O4.
- Bernini, Roberta,Mincione, Enrico,Barontini, Maurizio,Crisante, Fernanda
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experimental part
p. 8897 - 8904
(2010/04/23)
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- METHOD FOR PREPARING HYDROXYTYROSOL DERIVATIVES AND OF HYDROXYTYROSOL
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The present invention concerns a method for preparing hydroxytyrosol derivatives of general formula (III), where R=OCH3, or CF3 or an alkylic saturated or unsaturated, straight or cyclic, branched or not branched, chain from 1 to 31 carbon atoms, and for the preparation of hydroxytyrosol (IV).
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Page/Page column 7-8; 12-13
(2008/12/07)
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