51410-48-1Relevant articles and documents
Synthesis and antioxidant, anti-inflammatory and gastroprotector activities of anethole and related compounds
Freire, Rosemayre S.,Morais, Selene M.,Catunda Jr., Francisco Eduardo A.,Pinheiro, Diana C. S. N.
, p. 4353 - 4358 (2005)
Some derivatives of trans-anethole [1-methoxy-4-(1-propenyl)-benzene] (1) were synthesized, by introducing hydroxyl groups in the double bond of the propenyl moiety. Two types of reactions were performed: (i) oxymercuration/ demercuration that formed two products, the mono-hydroxyl derivative, 1-hydroxy-1-(4-methoxyphenyl)-propane (2) and in lesser extent the dihydroxyl derivative, 1,2-dihydroxy-1-(4-methoxyphenyl)-propane (3) and (ii) epoxidation with m-chloroperbenzoic acid that also led to the formation of two products, the dihydroxyl derivative (3) and the correspondent m-chloro-benzoic acid mono-ester, 1-hydroxy-1(4-methoxyphenyl)-2-m-chlorobenzoyl-propane (4). The structures of these compounds were confirmed mainly by mass, IR, 1H and 13C NMR spectral data. The activity of anethole and hydroxylated derivatives was evaluated using antioxidant, anti-inflammatory and gastroprotector tests. Compounds (2) and (3) were more active antioxidant agents than (1) and (4). In the anti-inflammatory assay, anethole showed lower activity than hydroxylated derivatives. Anethole and in lesser extent its derivatives 2 and 4 showed significant gastroprotector activity. All tested compounds do not alter significantly the total number of white blood cells.
Orthogonally protected 1,2-diols from electron-rich alkenes using metal-free olefin syn-dihydroxylation
Colomer, Ignacio,Barcelos, Rosimeire Coura,Christensen, Kirsten E.,Donohoe, Timothy J.
, p. 5880 - 5883 (2016/11/29)
A new method for the stereoselective metal-free syn-dihydroxylation of electron-rich olefins is reported, involving reaction with TEMPO/IBX in trifluoroethanol (TFE) or hexafluoroisopropanol (HFIP) and the addition of a suitable nucleophile. Orthogonally
Oxidative hydroxylation mediated by alkoxysulfonium ions
Ashikari, Yosuke,Nokami, Toshiki,Yoshida, Jun-Ichi
supporting information; experimental part, p. 938 - 941 (2012/05/05)
Oxidative hydroxylation of toluene derivatives via alkoxysulfonium ion intermediates was achieved by integration of anodic oxidation and hydrolysis to give benzyl alcohols which are also susceptible to oxidation. Alkenes were also oxidized to give 1,2-diols without overoxidation. The integration of electrochemical oxidative cyclization and hydrolysis was achieved using alkenes bearing a nitrogen atom in an appropriate position to give cyclic β-amino-substituted alcohols.
Metal-free dihydroxylation of alkenes using cyclobutane malonoyl peroxide
Jones, Kevin M.,Tomkinson, Nicholas C. O.
experimental part, p. 921 - 928 (2012/02/16)
Cyclobutane malonoyl peroxide (7), prepared in a single step from the commercially available diacid 6, is an effective reagent for the dihydroxylation of alkenes. Reaction of a chloroform solution of 7 with an alkene in the presence of 1 equiv of water at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (30-84%). With 1,2-disubstituted alkenes, the reaction proceeds with syn-selectivity (3:1 → 50:1). A mechanism consistent with experimental findings is proposed, which is supported by deuterium and oxygen labeling studies and explains the stereoselectivity observed. Alternative reaction pathways that are dependent on the structure of the starting alkene are also described leading to the synthesis of allylic alcohols and γ-lactones.
Ostensible enzyme promiscuity: Alkene cleavage by peroxidases
Mutti, Francesco G.,Lara, Miguel,Kroutil, Markus,Kroutil, Wolfgang
experimental part, p. 14142 - 14148 (2011/02/25)
Enzyme promiscuity is generally accepted as the ability of an enzyme to catalyse alternate chemical reactions besides the 'natural' one. In this paper peroxidases were shown to catalyse the cleavage of a C=C double bond adjacent to an aromatic moiety for selected substrates at the expense of molecular oxygen at an acidic pH. It was clearly shown that the reaction occurs due to the presence of the enzyme; furthermore, the reactivity was clearly linked to the hemin moiety of the peroxidase. Comparison of the transformations catalysed by peroxidase and by hemin chloride revealed that these two reactions proceed equally fast; additional experiments confirmed that the peptide backbone was not obligatory for the reaction and only a single functional group of the enzyme was required, namely in this case the prosthetic group (hemin). Consequently, we propose to define such a promiscuous activity as 'ostensible enzyme promiscuity'. Thus, we call an activity that is catalysed by an enzyme 'ostensible enzyme promiscuity' if the reactivity can be tracked back to a single catalytic site, which on its own can already perform the reaction equally well in the absence of the peptide backbone.
Ruthenium- and lipase-catalyzed DYKAT of 1,2-diols: an enantioselective synthesis of syn-1,2-diacetates
Edin, Michaela,Martin-Matute, Belen,Baeckvall, Jan-E.
, p. 708 - 715 (2007/10/03)
Regio- and stereoselective lipase-catalyzed kinetic resolutions were investigated for some unsymmetrical, secondary/secondary syn-diols. Candida antarctica lipase B-catalyzed transesterifications of a few aryl/alkyl- and alkyl/alkyl 1,2-diols were coupled
Radical α-C-H hydroxyalkylation of ethers and acetal
Yoshimitsu, Takehiko,Arano, Yoshimasa,Nagaoka, Hiroto
, p. 2342 - 2345 (2007/10/03)
(Chemical Equation Presented) Ethers and an acetal were found to undergo direct intermolecular addition to aldehydes under the Et3B/air conditions. This study presents a very unique and simple means for the radical α-C-H hydroxyalkylation of oxygen-containing compounds.
Spontaneous Hydrolysis Reactions of cis- and trans-β-Methyl-4-methoxystyrene Oxides (Anethole Oxides): Buildup of frans-Anethole Oxide as an Intermediate in the Spontaneous Reaction of cis-Anethole Oxide
Mohan, Ram S.,Gavardinas, Kostas,Kyere, Sampson,Whalen, Dale L.
, p. 1407 - 1413 (2007/10/03)
Rates and products of the reactions of trans- and cis-β-methyl-4-methoxystyrene oxides (1 and 2) (anethole oxides) and β,β-dimethyl-4-methoxystyrene oxide (3) in water solutions in the pH range 4-12 have been determined. In the pH range ca. 8-12, each of these epoxides reacts by a spontaneous reaction. The spontaneous reaction of trans-anethole oxide (1) yields ca. 40% of (4-methoxyphenyl)acetone and 60% of 1-(4-methoxyphenyl)-1,2-propanediols (erythro:threo ratio ca. 3:1). The spontaneous reaction of cis-anethole oxide is more complicated. The yields of diol and ketone products vary with pH in the pH range 8-11, even though there is not a corresponding change in rate. These results are interpreted by a mechanism in which 2 undergoes isomerization in part to the more reactive trans-anethole oxide (1), which subsequently reacts by acid-catalyzed and/or spontaneous reactions, depending on the pH, to yield diol and ketone products. The buildup of the intermediate trans-anethole oxide in the spontaneous reaction of cis-anethole oxide was detected by 1H NMR analysis of the reaction mixture. Other primary products of the spontaneous reaction of 2 are (4-methoxyphenyl)acetone (73%) and theo-1-(4-methoxyphenyl)-1,2-propanediol (ca. 3%). The rates and products of the spontaneous reaction of 2 and its β-deuterium-labeled derivative were determined, and the lack of significant kinetic and partitioning deuterium isotope effects indicates that the isomerization of 2 to ketone and to trans-anethole oxide must occur primarily by nonintersecting reaction pathways.
Synthesis of aromatic aldehydes by laccase-mediator assisted oxidation
Fritz-Langhals, Elke,Kunath, Brigitte
, p. 5955 - 5956 (2007/10/03)
Aromatic aldehydes can be prepared in aqueous medium by oxidation of the corresponding methyl aromatic compounds in the presence of oxygen, the enzyme laccase and catalytic amounts of various N-hydroxy compounds. Allylic alcohols also gave the corresponding aldehydes in good yield. Competing reactions reveal that the N-hydroxy compound is involved in the rate determining step of the reaction.
Side-chain fragmentation of arylalkanol radical cations. Carbon-carbon and carbon-hydrogen bond cleavage and the role of α- and β-OH groups
Baciocchi, Enrico,Bietti, Massimo,Putignani, Lorenza,Steenken, Steen
, p. 5952 - 5960 (2007/10/03)
A product analysis and kinetic study of the one-electron oxidation of a number of 1-arylpropanols, 1,2-diarylethanols, and some of their methyl ethers by potassium 12-tungstocobaltate(III) (abbreviated as Co(III)W) in aqueous acetic acid was carried out and complemented by pulse radiolysis experiments. The oxidations occur via radical cations which undergo side-chain fragmentation involving the C(α)-H and/or C(α)-C(β) bond. With 1-(4-methoxyphenyl)-2-methoxypropane (1), only deprotonation of the radical cation is observed. In contrast, removing the ring methoxy group leads to exclusive C-C bond cleavage in the radical cation. Replacing the side-chain β-OMe by β-OH, the radical cation undergoes both C-C and C-H bond cleavage, with both pathways being base catalyzed. C-C bond breaking in the radical cation is also enhanced by an α-OH group, as shown by 1-(4-methoxyphenyl)-2,2-dimethyl-1-propanol (7), where this pathway, which is also base catalyzed, is the only one observed. Interestingly, α- and β-OH groups exhibit a very similar efficiency in assisting the C-C bond cleavage route in the radical cations, as is evident from the kinetic and products study of the oxidation of 1-phenyl-2-(4-methoxyphenyl)ethanol (5) and 1-(4-methoxyphenyl)-2-phenylethanol (6) by Co(III)W, and from pulse radiolysis experiments on 5 and 6. C-C bond cleavage is the main reaction for both radical cations which exhibit a very similar rate of fragmentation (k = 2.0 and 3.2 x 104 s-1, respectively). In both fragmentation reactions a small solvent isotope effect, k(H2O)/k(D2O) (1.4 for 5.+ and 1.2 for 6.+) and negative activation entropies are observed. These data suggest that a key role in the assistance by α- or β-OH groups to C-C bond cleavage is played by hydrogen bonding or specific solvation of these groups. The kinetic study of the oxidations promoted by Co(III)W has also shown that when only one group, OH or OMe, is present in the side chain (either on C(α) or C(β)), the fragmentation step or both the electron transfer and fragmentation steps contribute to the overall oxidation rate. However, with an OH group on both carbons of the scissile bond, as in 1-(4-methoxyphenyl)-1,2-propanediol (9), the rate of C-C bond cleavage is so fast that the electron transfer step becomes rate determining.
