- Chemoenzymatic synthesis and radical scavenging of sulfated hydroxytyrosol, tyrosol, and acetylated derivatives
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Potential metabolites of bioactive compounds are important for their biological activities and as authentic standards for metabolic studies. The phenolic compounds contained in olive oil are an important part of the human diet, and therefore their potenti
- Begines, Paloma,Biedermann, David,Valentova, Katerina,Petraskova, Lucie,Pelantova, Helena,Maya, Ines,Fernandez-Bola?os, Jose G.,Krěn, Vladimír
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Read Online
- Chemoenzymatic Synthesis and α-Glucosidase Inhibitory Activity of Dimeric Neolignans Inspired by Magnolol
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A chemoenzymatic synthesis of a small library of dimeric neolignans inspired by magnolol (1) is reported. The 2-iodoxybenzoic acid (IBX)-mediated regioselective ortho-hydroxylation of magnolol is described, affording the bisphenols 6 and 7. Further magnol
- Pulvirenti, Luana,Muccilli, Vera,Cardullo, Nunzio,Spatafora, Carmela,Tringali, Corrado
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Read Online
- Optimization of lipase-catalyzed synthesis of acetylated tyrosol by response surface methodology
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The ability of a noncommercial immobilized lipase from Staphylococcus xylosus (SXLi) to catalyze the transesterification of tyrosol and ethyl acetate was investigated. Response surface methodology was used to evaluate the effects of the tempera
- Aissa, Imen,Bouaziz, Mohamed,Ghamgui, Hanen,Kamoun, Amel,Miled, Nabil,Sayadi, Sami,Gargouri, Youssef
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Read Online
- 3, 4-dihydroxyphenylethanol synthesis method
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An embodiment of the invention discloses a 3, 4-dihydroxyphenylethanol synthesis method which includes the steps: taking a compound I as a raw material to prepare a compound II under the action of a catalyst for standby application; performing reaction on the compound II prepared in the first step and strong acid, and extracting and concentrating a reactant to prepare a compound III; dissolving the compound III in a solvent to perform reaction under the of a catalyst to prepare a compound IV; performing diazo-reaction and acidic hydrolysis on the compound IV to generate 3, 4-dihydroxyphenylethanol. According to the 3, 4-dihydroxyphenylethanol synthesis method, raw materials are moderate in cost, mass production is easily implemented, the purity of the 3, 4-dihydroxyphenylethanol is higherthan 99%, and overall yield can reach 78% or more. The synthesis method is simple in reaction condition, special requirements for devices are omitted, the method is easily implemented in industrial production, and organic solvents can be completely recycled and reused in the whole preparation process.
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Paragraph 0033; 0034; 0038; 0039; 0043; 0044; 0048; 0049
(2019/04/02)
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- Chemoenzymatic synthesis of hydroxytyrosol monoesters and their suppression effect on nitric oxide production stimulated by lipopolysaccharides
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Fatty acid monoesters of hydroxytyrosol [2-(3,4-dihydroxyphenyl)ethanol] were synthesized in two steps from tyrosol (4-hydroxyphenylethanol) by successive Candida antarctica lipase B-catalyzed chemoselective acylation on the primary aliphatic hydroxy group over phenolic hydroxy group in tyrosol, and 2-iodoxybenzoic acid (IBX)-mediated hydroxylation adjacent to the remaining free phenolic hydroxy group. Examination of their suppression effects on nitric oxide production stimulated by lipopolysaccharides in RAW264.7 cells showed that hydroxytyrosol butyrate exhibited the highest inhibition (IC50 7.0 μM) among the tested compounds.
- Sakakura, Ayaka,Pauze, Martin,Namiki, Atsuhiro,Funakoshi-Tago, Megumi,Tamura, Hiroomi,Hanaya, Kengo,Higashibayashi, Shuhei,Sugai, Takeshi
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p. 185 - 191
(2019/02/05)
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- Tyrosol fatty acid ester compounds as well as preparation method and application thereof
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The invention discloses a tyrosol fatty acid ester compounds as well as a preparation method and application thereof, which belong to the technical field of biological medicines. According to the tyrosol fatty acid ester compounds, the chemical structure of tyrosol is derivatized, fatty acid is introduced into the structure, the structure is quite different from the structure of tyrosol, and the tyrosol fatty acid ester compounds have good bacteriostatic and anti-oxidation effects. The invention further provides the preparation method for the tyrosol fatty acid ester, i.e., with tyrosol, triphenyl phosphine and fatty acid as materials, tetrahydrofuran is added under the shielding of nitrogen, diisopropyl azodiformate is dripped under 0 DEG C, and after reaction, tyrosol fatty acid ester isobtained by column chromatography. The advantages are as follows: the tyrosol fatty acid ester compounds disclosed by the invention have good pharmacodynamic performance and high bioactivity; the reaction process of the preparation method has short steps and good selectivity, the target compounds can be obtained by one-step reaction, yield is high, and the preparation is environmentally friendly;and tyrosol fatty acid ester has bacteriostatic and anti-oxidation effects.
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Paragraph 0081-0083
(2019/01/16)
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- Lipase-mediated selective acetylation of primary alcohols in ethyl acetate
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An environmental friendly process to selectively acetylate primary alcohols was demonstrated. The esterification process consists of treatment of a primary alcohol in the presence of immobilized C. antarctica lipase (Novozyme-435) in ethyl acetate at room temperature. Primary alcohols were acetylated in the presence of secondary alcohols and phenols.
- de Souza, Ernane C.,Romero-Ortega, Moises,Olivo, Horacio F.
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supporting information
p. 287 - 290
(2017/12/29)
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- Isopropenyl acetate: A cheap and general acylating agent of alcohols under metal-free conditions
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Functionalized primary, secondary and tertiary alcohols are efficiently acetylated by isopropenyl acetate and catalytic p-TsOH.
- Temperini, Andrea,Minuti, Lucio,Morini, Tommaso,Rosati, Ornelio,Piazzolla, Francesca
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p. 4051 - 4053
(2017/09/27)
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- Tyrosol and hydroxytyrosol derivatives as antitrypanosomal and antileishmanial agents
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Trypanosomiasis and leishmaniasis keep being a real challenge for health and development of African countries. Existing treatments have considerable side effects and increase resistance of the parasites. We have measured antitrypanosomal and antileishmanial activity of natural phenols, tyrosol (TYR) and hydroxytyrosol (HT) and several of their esters and metabolites. We found significant IC50 values against Trypanosoma brucei for HT decanoate ester and HT dodecanoate ester (0.6 and 0.36 μM, respectively). This represents a large increase in activity with respect to HT (79 and 132 fold, respectively). Moreover, both compounds displayed a high selectivity index against MRC-5, a non-tumoral human cell line (118 and 106, respectively). Then, we synthesized a focused library of compounds to explore structure-activity. We found the ether and thiourea analogs of HT decanoate ester and HT dodecanoate ester also showed IC50 values against T. brucei in the low micromolar range. In conclusion, the di-ortho phenolic ring and medium size alkyl chain are essential for activity whereas the nature of the chemical bond among them seems less important.
- Belmonte-Reche, Efres,Martínez-García, Marta,Pe?alver, Pablo,Gómez-Pérez, Verónica,Lucas, Ricardo,Gamarro, Francisco,Pérez-Victoria, José María,Morales, Juan Carlos
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p. 132 - 140
(2016/05/24)
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- Cutinase from Fusarium oxysporum catalyzes the acylation of tyrosol in an aqueous medium: Optimization and thermodynamic study of the reaction
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Recently, tyrosol has gained attention as a result of its many pharmacological properties and due to the fact that it can be isolated from cheap and abundant resources. Lipophilic tyrosyl esters, which are scarce in nature, have proven in certain cases to acquire improved biological activity compared to tyrosol itself, increasing their potential use in the food and cosmeceutical industries. The enzymatic approach for the synthesis of such esters has prevailed, as it is "green", compared to chemical practices. We hereby report the enzymatic synthesis of tyrosyl esters of various aliphatic fatty acids performed by a recombinant cutinase from Fusarium oxysporum (FoCut5a). The reaction system used consists of an aqueous phase saturated with the corresponding fatty-acid vinyl ester, which played the role of the acyl donor. We also proceeded to the study of several parameters on the yield of the tyrosyl butyrate ester synthesis. The maximum yield achieved was 60.7% after 4 h at 20 °C, in pH 7.0, with initial tyrosol concentration of 12.5 mM and using 5 μg FoCut5a mL-1 reaction as catalyst. The optimum reaction conditions can be considered mild, highlighting the environmentally friendly nature of this reaction, along with the fact that there are not any harmful reagents involved. Additionally, the use of two thermodynamic models, Conductor-like Screening Model for Real Solvents (COSMO-RS) and UNIquac Functional-group Activity Coefficients (UNIFAC), were employed for the prediction of reactants' and products' solubilities and their distribution in the reaction biphasic system, aiming to correlate the reaction yields with these important thermodynamic quantities and understand the ability of this enzymatic reaction in synthesizing tyrosyl esters.
- Nikolaivits, Efstratios,Norra, Giannis-Florjan,Voutsas, Epaminondas,Topakas, Evangelos
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- Structural and catalytic characterization of a fungal baeyer-villiger monooxygenase
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Baeyer-Villiger monooxygenases (BVMOs) are biocatalysts that convert ketones to esters. Due to their high regio-, stereo- and enantioselectivity and ability to catalyse these reactions under mild conditions, they have gained interest as alternatives to chemical Baeyer-Villiger catalysts. Despite their widespread occurrence within the fungal kingdom, most of the currently characterized BVMOs are from bacterial origin. Here we report the catalytic and structural characterization of BVMOAFL838 from Aspergillus flavus. BVMOAFL838 converts linear and aryl ketones with high regioselectivity. Steady-state kinetics revealed BVMOAFL838 to show significant substrate inhibition with phenylacetone, which was more pronounced at low pH, enzyme and buffer concentrations. Para substitutions on the phenyl group significantly improved substrate affinity and increased turnover frequencies. Steady-state kinetics revealed BVMOAFL838 to preferentially oxidize aliphatic ketones and aryl ketones when the phenyl group are separated by at least two carbons from the carbonyl group. The X-ray crystal structure, the first of a fungal BVMO, was determined at 1.9 A and revealed the typical overall fold seen in type I bacterial BVMOs. The active site Arg and Asp are conserved, with the Arg found in the ginh position. Similar to phenylacetone monooxygenase (PAMO), a two residue insert relative to cyclohexanone monooxygenase (CHMO) forms a bulge within the active site. Approximately half of the gvariableh loop is folded into a short ?-helix and covers part of the active site entry channel in the non-NADPH bound structure. This study adds to the current efforts to rationalize the substrate scope of BVMOs through comparative catalytic and structural investigation of different BVMOs.
- Ferroni, Felix Martin,Tolmie, Carmien,Smit, Martha Sophia,Opperman, Diederik Johannes
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- Carbon nanotubes supported tyrosinase in the synthesis of lipophilic hydroxytyrosol and dihydrocaffeoyl catechols with antiviral activity against DNA and RNA viruses
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Hydroxytyrosol and dihydrocaffeoyl catechols with lipophilic properties have been synthesized in high yield using tyrosinase immobilized on multi-walled carbon nanotubes by the Layer-by-Layer technique. All synthesized catechols were evaluated against a large panel of DNA and RNA viruses, including Poliovirus type 1, Echovirus type 9, Herpes simplex virus type 1 (HSV-1), Herpes simplex virus type 2 (HSV-2), Coxsackievirus type B3 (Cox B3), Adenovirus type 2 and type 5 and Cytomegalovirus (CMV). A significant antiviral activity was observed in the inhibition of HSV-1, HSV-2, Cox B3 and CMV. The mechanism of action of the most active dihydrocaffeoyl derivative was investigated against a model of HSV-1 infection.
- Botta, Giorgia,Bizzarri, Bruno Mattia,Garozzo, Adriana,Timpanaro, Rossella,Bisignano, Benedetta,Amatore, Donatella,Palamara, Anna Teresa,Nencioni, Lucia,Saladino, Raffaele
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supporting information
p. 5345 - 5351
(2015/11/11)
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- Facile esterification of alcohols with 2-Acyl-4,5-dichloropyridazin-3(2 H)-ones under Friedel-Crafts conditions
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This paper describes the esterification of aromatic and aliphatic alcohols by using 2-acyl-4,5-dichloropyridazin-3(2H)-ones as an acyl source under Friedel-Crafts conditions. Twelve alcohols were reacted with four 2-acyl-4,5-dichloropyridazin-3(2H)-ones in the presence of AlCl3 in tetrahydrofuran at room temperature to give the corresponding esters in moderate to excellent yields. Thus, 2-acylpyridazin-3(2H)-ones serve as good and atom-economic acyl sources for the esterification of aromatic alcohols under Friedel-Crafts conditions, representing a rapid, practical, and efficient method of esterification. Georg Thieme Verlag Stuttgart. New York.
- Kim, Bo Ram,Sung, Gi Hyeon,Ryu, Ki Eun,Yoon, Hyo Jae,Lee, Sang-Gyeong,Yoon, Yong-Jin
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p. 1909 - 1915
(2014/08/18)
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- Reductive removal of methoxyacetyl protective group using sodium borohydride
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Herein, we have developed a mild and selective reductive deprotection method for the MAc protected alcohols using sodium borohydride. The new deprotection conditions provide a complete orthogonality between O-MAc and other protecting groups such as tert-butyl ester, N-Boc, Fmoc, Cbz, O-TBDMS, N-benzyl, O-benzyl, O-acetyl, N-acetyl, N-MAc, etc. In addition to O-MAc deprotection, this method is also applicable for S-MAc deprotection.
- Gadekar, Pradip K.,Hoermann, Maryann,Corbo, Faith,Sharma, Rajiv,Sarveswari,Roychowdhury, Abhijit
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p. 503 - 506
(2014/01/06)
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- Functional divergence between closely related Baeyer-Villiger monooxygenases from Aspergillus flavus
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Baeyer-Villiger monooxygenases (BVMOs) catalyse the chemo-, regio- and enantioselective oxidation of ketones to esters and lactones. To date, most of the cloned BVMOs available are derived from bacteria, although Baeyer-Villiger oxidations using fungi have frequently been demonstrated. Here we report the cloning and characterization of four BVMOs from the fungus Aspergillus flavus NRRL3357. Phylogenetic analysis shows these four BVMOs to cluster in a distinct group apart from other well-characterized BVMOs including cyclohexanone, phenylacetone and 4-hydroxyacetophenone monooxygenase. Building on the Grogan classification/clustering of BVMOs, we have designated this new group of BVMOs, Group VI. Group VI BVMOs show an early divergence from the cyclopentanone monooxygenase (CPMO) type BVMOs (Group I). Substrate profiling using cyclic, bicyclic, aliphatic and aryl ketones show a clear divergence in function and specificity not only between this new group of BVMOs and the CPMO-type BVMOs, but also between the four A. flavus BVMO paralogues despite their high sequence similarity. This study not only contributes to the growing number of available BVMOs, but also addresses the current classification of Type I BVMOs, and the usefulness of phylogenetic clustering and prediction of function and selectivity when genome-mining is used to search for new biocatalysts.
- Ferroni,Smit,Opperman
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- Selective acylation of the phenolic hydroxyl of (hydroxyalkyl)phenols by using vinyl carboxylates as acyl donors in the presence of rubidium fluoride
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Highly selective acylation of the phenolic hydroxy group can be achieved with (hydroxyalkyl)phenols carrying both alcoholic and phenolic hydroxyls by the use of vinyl carboxylates as acyl donors in the presence of rubidium fluoride.
- Miyazawa, Toshifumi,Yamamoto, Masato,Danjo, Hiroshi
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p. 1351 - 1354
(2013/10/01)
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- A lewis acid-promoted pinner reaction
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Carbonitriles and alcohols react in a Lewis acid-promoted Pinner reaction to carboxylic esters. Best results are obtained with two equivalents of trimethylsilyl triflate as Lewis acid. Good yields are achieved with primary alcohols and aliphatic or benzylic carbonitriles, but the straightforward synthesis of acrylates and benzoates starting with acrylonitrile and benzonitrile, respectively, is similarly possible. Phenols are not acylated under these reaction conditions. The method has been used for the first total synthesis of the natural product monaspilosin. In the reaction of benzyl alcohols variable amounts of amides are formed in a Ritter-type side reaction.
- Pfaff, Dominik,Nemecek, Gregor,Podlech, Joachim
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supporting information
p. 1572 - 1577
(2013/10/22)
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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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- Monolayer properties of synthesized tyrosyl esters
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Lipase-catalyzed synthesis of eight fatty acid tyrosyl esters (TyC 2 to TyC18:1) was investigated using non commercial lipases from Rhizopus oryzae and Staphylococcus xylosus immobilized onto CaCO3. The monomolecular film technique was used to compare the ability of the various synthesized tyrosyl fatty acid esters to form a stable monolayer at the air/water interface and their capacity to interact with a phospholipid monolayer. The measurements of surface pressure versus the molecular area shows that, in contrast to tyrosol esterified with short and medium chains (acetic (TyC2), propionic (TyC3), caprylic (TyC8) and capric (TyC10) acids), tyrosol esterified with long chains: lauric (TyC12), palmitic (TyC16), stearic (TyC18) and oleic (TyC18:1) acids are able to form a stable monolayer at the air/water interface. A direct correlation was observed between the length of the saturated acyl chain of the derivatives and their corresponding collapse pressures. The presence of unsaturation reduces the collapse pressure value. The interaction of tyrosyl esters with a phospholipid monolayer was studied and the critical surface pressure (πc) of each ester was determined. Only medium and long chain (TyC8 to TyC18:1) derivatives esters were found to interact efficiently with DiC12PC film.
- Aissa, Imen,Leclaire, Julien,Ali, Yassine Ben,Frikha, Fakher,Gargouri, Youssef
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p. 125 - 130
(2012/11/13)
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- An efficient, economical synthesis of hydroxytyrosol and its protected forms via Baeyer-Villiger oxidation
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An efficient and practical preparation of hydroxytyrosol and its orthogonally-protected forms was developed from inexpensive tyrosol. The utilization of Baeyer-Villiger oxidation enables the chemoselective introduction of a phenolic hydroxyl group in good yield.
- Piersanti, Giovanni,Retini, Michele,Espartero, José L.,Madrona, Andres,Zappia, Giovanni
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scheme or table
p. 4938 - 4940
(2011/10/07)
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- Laccase-mediated oxidation of phenolic derivatives
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The laccase-catalyzed oxidation of para-alkyl phenols (p-cresol, 3,4-dimethylphenol, tyrosol, 2′-O-acetyl-tyrosol) in biphasic systems has been investigated. With all the substrates compounds similar to the so-called "Pummerer's ketone" could be isolated
- Navarra, Cristina,Goodwin, Candice,Burton, Stephanie,Danieli, Bruno,Riva, Sergio
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experimental part
p. 52 - 57
(2010/12/19)
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- Surface-active properties of lipophilic antioxidants tyrosol and hydroxytyrosol fatty acid esters: A potential explanation for the nonlinear hypothesis of the antioxidant activity in oil-in-water emulsions
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Our group has recently observed a nonlinear tendency in antioxidant capacity of different hydroxytyrosol fatty acid esters in fish oil-in-water emulsions, where a maximum of antioxidant efficiency appeared for hydroxytyrosol octanoate. These results appea
- Lucas, Ricardo,Comelles, Francisco,Alcantara, David,Maldonado, Olivia S.,Curcuroze, Melanie,Parra, Jose L.,Morales, Juan C.
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experimental part
p. 8021 - 8026
(2011/09/20)
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- Thermolysis of 4-(ω-hydroxyalkyl)-2,6-di-tert-butylphenols
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The process of thermolysis of tert-butylated hydroxyalkyl phenols includes de-tert-butylation, etherification, and fragmentation of the hydroxyalkyl group. On the basis of the proposed schemes of the mechanism of thermal de-tert-butylation the path of the search for catalysts for the synthesis of 4-hydroxyalkylphenols is defined and transformations of the by-products into biologically active substances were considered.
- Krysin,Egorova,Vasil'Ev
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body text
p. 275 - 283
(2010/07/15)
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- A highly efficient and reusable mesoporous supported Co(II) catalyst for chemoselective deprotection of aryl acetates
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Chemoselective deprotection of aryl acetates is successfully carried out in excellent yield using a mesoporous silica-supported (Salen) Co(II) catalyst. The catalyst shows high thermal stability and also can be recovered and reused at least 10 times without any significant loss of its catalytic activity. The present process is environmentally benign and economical.
- Rajabi, Fatemeh
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experimental part
p. 7256 - 7258
(2010/02/28)
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- Microwave-accelerated selective acylation of (hydroxyalkyl)phenols using acid chlorides
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Highly selective acylation of the alcoholic hydroxy group can be achieved with (hydroxyalkyl)phenols carrying both alcoholic and phenolic hydroxyls by the use of the most common acylating agents, acid chlorides, under microwave irradiation. Copyright Tayl
- Miyazawa, Toshifumi,Yamamoto, Masato,Maeda, Yuki
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experimental part
p. 1092 - 1099
(2009/09/06)
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- COMPOUNDS
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The present invention provides the use of a compound of the Formula: (I) wherein R1 is C1-5 alkoxy, OCOC1-3Alkyl, O(CH2)2O(CH2)2O(CH2)2OMe, O(CH2)2O(CH2)2O(CH2)2OH or OH; R2 is H, (CH2)nOH, OCH3, Hal or (II) or (III) R3 is H or (CH2)nOH; and R4 is C1-6 alkyl, optionally substituted by one or more of Hal, OH, COCH3, NH2, NHCH3, NHMe, NMe2, OCOCH3, CO2H or esters or amides thereof where n is 1-5; and pharmaceutically acceptable salts thereof, in the manufacture of a medicament for use in modulating PKB activity.
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Page/Page column 14-15
(2009/09/08)
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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 9
(2008/12/07)
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- TX-2152: A conformationally rigid and electron-rich diyne analogue of FTY720 with in vivo antiangiogenic activity
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We designed FTY720 analogues with conformationally rigid and electron-rich acetylenic chains as antiangiogenic agents (the monoyne 1: TX-2148, the diyne 2: TX-2152, the triyne 3: TX-2256). Molecular orbital (MO) calculations of our designed acetylenic ana
- Nakayama, Shinichi,Uto, Yoshihiro,Tanimoto, Kanako,Okuno, Yasuhiro,Sasaki, Yuki,Nagasawa, Hideko,Nakata, Eiji,Arai, Ken,Momose, Kaori,Fujita, Tetsuro,Hashimoto, Toshihiro,Okamoto, Yasuko,Asakawa, Yoshinori,Goto, Satoru,Hori, Hitoshi
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experimental part
p. 7705 - 7714
(2009/04/06)
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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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- Mild debenzylation of aryl benzyl ether with BCl3 in the presence of pentamethylbenzene as a non-lewis-basic cation scavenger
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Scope and limitations of the debenzylation conditions for aryl benzyl ether, which was developed during our synthetic studies on yatakemycin, were investigated. The chemoselective debenzylation proceeds at low temperature with a combination of BCl3 and pentamethylbenzene as a cation scavenger in the presence of various functional groups.
- Okano, Kentaro,Okuyama, Kei-Ichiro,Fukuyama, Tohru,Tokuyama, Hidetoshi
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scheme or table
p. 1977 - 1980
(2009/04/07)
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- Biological activity of acetylated phenolic compounds
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In recent years an effort has been made to isolate and identify biologically active compounds that are included in the Mediterranean diet. The existence of naturally occurring acetylated phenolics, as well as studies with synthetic ones, provide evidence that acetyl groups could be correlated with their biological activity. Platelet activating factor (PAF) is implicated in atherosclerosis, whereas its inhibitors seem to play a protective role against cardiovascular disease. The aim of this study was to examine the biological activity of resveratrol and tyrosol and their acetylated derivatives as inhibitors of PAF-induced washed rabbit platelet aggregation. Acetylation of resveratrol and tyrosol was performed, and separation was achieved by HPLC. Acetylated derivatives were identified by negative mass spectrometry. The data showed that tyrosol and its monoacetylated derivatives act as PAF inhibitors, whereas diacetylated derivatives induce platelet aggregation. Resveratrol and its mono- and triacetylated derivatives exert similar inhibitory activity, whereas the diacetylated ones are more potent inhibitors. In conclusion, acetylated phenolics exert the same or even higher antithrombotic activity compared to the biological activity of the initial one.
- Fragopoulou, Elizabeth,Nomikos, Tzortzis,Karantonis, Haralabos C.,Apostolakis, Constantinos,Pliakis, Emmanuel,Samiotaki, Martina,Panayotou, George,Antonopoulou, Smaragdi
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- A photoreactive analogue of the immunosuppressant FTY720
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An azido group was incorporated into the immunomodulatory agent FTY720, accomplishing the first synthesis of a photoactivatable analogue of this ligand (2) in 9 steps from 2-(4-hydroxyphenyl)ethanol and in 34% overall yield. The key steps are formation of
- Sun, Chaode,Bittman, Robert
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p. 2200 - 2202
(2007/10/03)
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- Acetylation of alcohols catalyzed by dodeca-tungsto(molybdo)phosphoric acid
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Acetylation of primary, secondary, and tertiary alcohols was carried out in some refluxing alkyl acetates and in two carboxylic acids with the participation of catalytic amounts of H3PW12O 40, H3PMo12O40, and H 14P5W30O110 with good yields and high stereo(regio)specificity under mild reaction condition. H 3PW12O40 and H3PMo 12O40 have also shown excellent reactivity in the formylation of 1-butanol with ethyl formate at room temperature and in short reaction times. Heteropolyacid catalysts could be separated after a simple work up and reused for several times. Springer-Verlag 2006.
- Tayebee, Reza,Alizadeh, Mohammad H.
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p. 1063 - 1069
(2007/10/03)
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- Molecular iodine catalyzed selective acetylation of alcohols with vinyl acetate
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Molecular iodine is found to catalyze the acetylation of alcohols efficiently with vinyl acetate. The reaction is mild and selective with good to high yields. Molecular iodine displays significant functional group tolerance, being compatible with methoxy, double bonds, spiroketals, ketals and phenolic hydroxyl functions.
- Bosco, J.W. John,Agrahari, Aditya,Saikia, Anil K.
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p. 4065 - 4068
(2007/10/03)
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- Iron-catalyzed cross-coupling reactions. A scalable synthesis of the immunosuppressive agent FTY720
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A chemo- and regioselective cross-coupling reaction of the functionalized aryl triflate 5 with octylmagnesium bromide catalyzed by cheap, nontoxic, and environmentally benign Fe(acac)3 sets the basis for a practical and scaleable synthesis of the octylbenzene derivative 6, which serves as a key building block for the preparation of FTY720 (1). This 2-amino-1,3-propanediol derivative shows highly promising immunosuppressive properties and is currently in human clinical phase III trials.
- Seidel, Guenter,Laurich, Daniel,Fuerstner, Alois
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p. 3950 - 3952
(2007/10/03)
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- Second Generation of cycloSal-Pronucleotides with Esterase-Cleavable Sites: The "Lock-In"-Concept
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A conceptual extension of the cycloSal-pronucleotide approach is presented. The characteristic feature of the new cycloSal-derivatives of the anti-HIV active nucleoside analogue d4T 1 is the incorporation of an enzymatically cleavable carboxylic ester moiety with the intention to trap the triesters inside cells ("lock-in"-concept). CycloSal-triesters bearing different ester groups in the 3-or 5-position of the cycloSal-moiety are described. Surprisingly, only acetyl-and levulinyl esters are cleaved readily in CEM cell extracts while alkyl esters were found to be stable. Nevertheless, in in-vitro anti-HIV assays most of the compounds achieve the thymidine-kinase bypass, thus proving that they act at least as nucleotide delivery systems.
- Meier, Chris,Ruppel, Manuel F. H.,Vukadinovic, Dalibor,Balzarini, Jan
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- Palladium(II) chloride catalyzed selective acetylation of alcohols with vinyl acetate
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PdCl2 can catalyze the acetylation of primary and secondary alcohols with vinyl acetate. The reaction is selective and mild with high yields. Tertiary alcohols, phenols and amines are unaffected under these reaction conditions.
- Bosco,Saikia, Anil K.
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p. 1116 - 1117
(2007/10/03)
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- Highly efficient and versatile acetylation of alcohols catalyzed by cerium(III) triflate
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Cerium(III) triflate is a powerful catalyst for the acetylation of alcohols. The reaction works well for a large variety of simple and functionalized alcohols, without isomerisation of chiral centres. Changes of hydroxyl protective groups are possible in a one-pot procedure. The catalyst can be easily recycled.
- Dalpozzo, Renato,De Nino, Antonio,Maiuolo, Loredana,Procopio, Antonio,Nardi, Monica,Bartoli, Giuseppe,Romeo, Roberto
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p. 5621 - 5624
(2007/10/03)
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- A mild, highly selective and remarkably easy procedure for deprotection of aromatic acetates using ammonium acetate as a neutral catalyst in aqueous medium
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Ammonium acetate was found to catalyze efficiently the selective deprotection of aromatic acetates in the presence of various sensitive functionalities in aqueous methanol under neutral conditions at room temperature to yield the corresponding phenols in excellent yields. The method has been utilized for deprotection of acetates of several naturally occurring bioactive phenolic compounds and for preparation of venkatasin, a natural coumarino-lignan, from the anticancer compound cleomiscosin A.
- Ramesh,Mahender,Ravindranath,Das, Biswanath
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p. 1049 - 1054
(2007/10/03)
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- Simple, efficient, and selective deprotection of phenolic methoxymethyl ethers using silica-supported sodium hydrogen sulfate as a heterogeneous catalyst
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A simple and efficient method has been developed for chemoselective deprotection of phenolic methoxymethyl (MOM) ethers using silica-supported sodium hydrogen sulfate as a heterogeneous catalyst. The conversions occur at room temperature, and the yields of the deprotected phenols are excellent. The method is suitable for deprotection of phenolic MOM ethers of multifunctional bioactive natural products.
- Ramesh,Ravindranath,Das, Biswanath
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p. 7101 - 7103
(2007/10/03)
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- Selective acetylation of aliphatic hydroxyl group in the presence of phenolic hydroxyl group using silica gel supported BF3 catalyst
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Selective acetylation of aliphatic hydroxyl group in the presence of phenolic hydroxyl group was achieved conveniently and efficiently by treatment with EtOAc in the presence of silica gel supported BF3 catalyst.
- Das, Biswanath,Venkataiah,Madhusudhan
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p. 249 - 252
(2007/10/03)
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- Determination of phenols, flavones, and lignans in virgin olive oils by solid-phase extraction and high-performance liquid chromatography with diode array ultraviolet detection
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A simple analytical method for the quantitative determination of phenols, flavones, and lignans in virgin olive oils was developed. The polar fraction was isolated from small amounts of oil sample (2.5 g) by solid-phase extraction (SPE) using diol-phase cartridges, and the extract was analyzed by reversed-phase HPLC coupled with diode array LTV detection. Chromatographic separation of pinoresinol, cinnamic acid, and 1-acetoxypinoresinol was achieved. Repeatability (RSD 90%), and response factors for each identified component were determined. SPE on amino-phase cartridges was used for isolating acidic phenols and as an aid for phenol identification. For the first time, 2-(4-hydroxyphenyl)ethyl acetate was detected in olive oils. The aldehydic structure of the ligstroside aglycon was confirmed by NMR spectroscopy. The colorimetric determination of total o-diphenolic compounds by reaction with molybdate was consistent with their HPLC determination. Differences between results obtained by liquid-liquid extraction and SPE were not statistically significant.
- Mateos, Raquel,Espartero, Jose Luis,Trujillo, Mariana,Rios,Leon-Camacho, Manuel,Alcudia, Felipe,Cert, Arturo
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p. 2185 - 2192
(2007/10/03)
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- Mild and practical acylation of alcohols with esters or acetic anhydride under distannoxane catalysis
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Distannoxane catalysts effect acylation of alcohols by action of esters and acetic anhydride. In particular, use of enol esters provides an extremely useful method. Primary alcohols are acylated in preference to secondary ones as well as phenol. Both acid- and base-sensitive functional groups remain intact. Especially unique is the discrimination of thio function which is completely tolerant under the present reaction conditions. This method is highly practical since operation is quite simple. Esters and solvents can be used without purification and no inert atmosphere is necessary. The products can be isolated simply by column chromatography or distillation without aqueous workup.
- Orita, Akihiro,Sakamoto, Katsumasa,Hamada, Yuji,Mitsutome, Akihiro,Otera, Junzo
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p. 2899 - 2910
(2007/10/03)
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- An Extremely Powerful Acylation Reaction of Alcohols with Acid Anhydrides Catalyzed by Trimethylsilyl Trifluoromethanesulfonate
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Trimethylsilyl trifluoromethanesulfonate is an excellent catalyst for the acylation of alcohols with acid anhydrides. Highly functionalized primary, secondary, tertiary, and allylic alcohols, and phenols, were acylated cleanly and efficiently and in a fraction of the time used under the standard DMAP conditions.
- Procopiou, Panayiotis A.,Baugh, Simon P.D.,Flack, Stephen S.,Inglis, Graham G.A.
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p. 2342 - 2347
(2007/10/03)
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- Lipase-catalysed chemoselective monoacetylation of hydroxyalkylphenols and chemoselective removal of a single acetyl group from their diacetates
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It was demonstrated that Pseudomonas cepacia PS lipase adsorbed on Celite, has the ability to catalyse the chemoselective monoacetylation of various hydroxyalkylphenols or the chemoselective removal of a single acetyl group from the corresponding acetate.
- Allevi, Pietro,Ciuffreda, Pierangela,Longo, Alessandra,Anastasia, Mario
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p. 2915 - 2924
(2007/10/03)
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- Biogeneration and Biodegradation of Raspberry Ketone in the Fungus Beauveria bassiana
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In growing cultures of the fungus Beauveria bassiana (ATCC 7159) the incubation of 4-(4′-hydroxyphenyl)but-3-en-2-one (p-hydroxybenzylidenacetone, 3), of 4-(4′-hydroxyphenyl)butan-2-one (raspberry ketone, 1), and of the S and R,S forms of 4-(4′-hydroxyphenyl)butan-2-ol (2) yields 2-(4′-hydroxyphenyl)ethanol (tyrosol, 4) as a final product. The experiments support the view that the actual substrate for the Baeyer-Villiger-type degradation is raspberry ketone (1) and that there is a kinetic preference in the microbial enzymatic system for the oxidation to 1 of the S form of the 4-(4′-hydroxyphenyl)butan-2-ol (2).
- Fuganti, Claudio,Mendozza, Monica,Joulain, Daniel,Minut, Jose,Pedrocchi-Fantoni, Giuseppe,Piergianni, Valentino,Servi, Stefano,Zucchi, Gioia
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p. 3616 - 3619
(2007/10/03)
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- REACTION OF AROMATIC HYDROCARBONS WITH 2-(3,5-DI-TERT-BUTYL-4-HYDROXYPHENYL)ETHYL ACETATE AT HETEROPOLY ACIDS
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When 2-(3,5-di-tert-butyl-4-hydroxyphenyl)ethyl acetate is heated with aromatic hydrocarbons at the solid heteropoly acid (H3PW12O4/SiO2), the following three types of reactions take place simultaneously: de-tert-butylation and condensation of the phenols with the formation of 1,2-diarylethanes and tert-butylation of the aromatic hydrocarbons.
- Titova, T. F.,Krysin, A. P.
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p. 1593 - 1596
(2007/10/03)
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- Regio- and Chemo-selective Properties of Lipase from Candida cylindracea
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Lipase from Candida cylindracea allows discrimination between the two connectively non-equivalent hydroxy groups in primary diols or their esters via acylation-hydrolysis, with high regioselectivity.The same technique is used to distinguish between hydroxy groups of different nature in phenolic compounds.
- Pedrocchi-Fantoni, Giuseppe,Servi, Stefano
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p. 1029 - 1034
(2007/10/02)
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