5706-85-4Relevant articles and documents
One-Pot Enzymatic-Chemical Cascade Route for Synthesizing Aromatic α-Hydroxy Ketones
Wang, Lei,Song, Wei,Wang, Binju,Zhang, Yan,Xu, Xin,Wu, Jing,Gao, Cong,Liu, Jia,Chen, Xiulai,Chen, Jinghua,Liu, Liming
, p. 2808 - 2818 (2021/03/15)
2-Hydroxyacetophenone (2-HAP) is an important building block for the production of a series of natural products and pharmaceuticals; however, there is no safe, efficient, and economical method for 2-HAP synthesis. Here, a one-pot enzymatic-chemical cascade route was designed for synthesizing 2-HAP based on retrosynthetic analysis. First, a spontaneous proton-transfer reaction was designed using a computational simulation that enabled 2-HAP synthesis from the isomer 2-hydroxy-2-phenylacetaldehyde. A route for 2-hydroxy-2-phenylacetaldehyde synthesis was then constructed by introducing the unnatural substrate glyoxylic acid into a C-C ligation reaction catalyzed by Candida tropicalis pyruvate decarboxylase. Assembly and optimization of this enzymatic-chemical cascade route resulted in a final yield of 92.7%. Furthermore, stereospecific carbonyl reductases were introduced to construct a synthetic application platform that enabled further transformation of 2-HAP into (S)- and (R)-1-phenyl-1,2-ethanediol. This method of cascading spontaneous chemical and enzymatic reactions to synthesize chemicals offers insight into avenues for synthesizing other valuable chemicals.
Supramolecular Storage and Controlled Photorelease of an Oxidizing Agent using a Bambusuril Macrocycle
Torti, Edoardo,Havel, Václav,Yawer, Mirza A.,Ludvíková, Lucie,Babiak, Michal,Klán, Petr,Sindelar, Vladimir
supporting information, p. 16768 - 16772 (2017/12/02)
The oxidizing ability of peroxodisulfate upon complexation inside the Bambusuril macrocycle cavity is inhibited. This dianionic agent can be released on demand from its stable 1:1 complex in water (log Ka=6.9 m?1) by addition of a more strongly bound anion, such as iodide (log Ka=7.1 m?1), which can also be delivered in situ upon irradiation from a 4-hydroxyphenacyl iodide derivative with spatial and temporal precision. The oxidizing properties of peroxodisulfate ions liberated from the complex recover and can take part in subsequent chemical transformations.
Selective oxidation of aliphatic C-H bonds in alkylphenols by a chemomimetic biocatalytic system
Du, Lei,Dong, Sheng,Zhang, Xingwang,Jiang, Chengying,Chen, Jingfei,Yao, Lishan,Wang, Xiao,Wan, Xiaobo,Liu, Xi,Wangi, Xinquan,Huang, Shaohua,Cui, Qiu,Feng, Yingang,Liu, Shuang-Jiang,Li, Shengying
, p. E5129 - E5137 (2017/07/04)
Selective oxidation of aliphatic C-H bonds in alkylphenols serves significant roles not only in generation of functionalized intermediates that can be used to synthesize diverse downstream chemical products, but also in biological degradation of these environmentally hazardous compounds. Chemo-, regio-, and stereoselectivity; controllability; and environmental impact represent the major challenges for chemical oxidation of alkylphenols. Here, we report the development of a unique chemomimetic biocatalytic system originated from the Gram-positive bacterium Corynebacterium glutamicum. The system consisting of CreHI (for installation of a phosphate directing/ anchoring group), CreJEF/CreG/CreC (for oxidation of alkylphenols), and CreD (for directing/anchoring group offloading) is able to selectively oxidize the aliphatic C-H bonds of p-And m-Alkylated phenols in a controllable manner. Moreover, the crystal structures of the central P450 biocatalyst CreJ in complex with two representative substrates provide significant structural insights into its substrate flexibility and reaction selectivity.
Two-Step, Catalytic C-C Bond Oxidative Cleavage Process Converts Lignin Models and Extracts to Aromatic Acids
Wang, Min,Lu, Jianmin,Zhang, Xiaochen,Li, Lihua,Li, Hongji,Luo, Nengchao,Wang, Feng
, p. 6086 - 6090 (2016/09/09)
We herein report a two-step strategy for oxidative cleavage of lignin C-C bond to aromatic acids and phenols with molecular oxygen as oxidant. In the first step, lignin β-O-4 alcohol was oxidized to β-O-4 ketone over a VOSO4/TEMPO [(2,2,6,6-tetramethylpiperidin-1-yl)oxyl)] catalyst. In the second step, the C-C bond of β-O-4 linkages was selectively cleaved to acids and phenols by oxidation over a Cu/1,10-phenanthroline catalyst. Computational investigations suggested a copper-oxo-bridged dimer was the catalytically active site for hydrogen-abstraction from Cβ-H bond, which was the rate-determining step for the C-C bond cleavage.
Chemoselective oxidant-free dehydrogenation of alcohols in lignin using Cp?Ir catalysts
Zhu, Rui,Wang, Bing,Cui, Minshu,Deng, Jin,Li, Xinglong,Ma, Yingbo,Fu, Yao
supporting information, p. 2029 - 2036 (2016/04/19)
A remarkably effective method of chemoselective dehydrogenation of alcohols in lignin has been developed with an iridium catalyst. An additional operation of Zn/NH4Cl via a two-step one pot process could further promote the cleavage of the C-O bond in β-O-4 units in lignin. And this reaction system was also applicable to native lignin as the molecular weight of native lignin decreased obviously as detected by gel permeation chromatography (GPC). Additionally, this is the first to date generation of the by-product H2 from native lignin and the by-product was straightforwardly captured by 1-decene. A probable mechanistic pathway was also proposed with the help of density functional theory (DFT) calculations.
Substituted phenacyl molecules and photoresponsive polymers
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, (2016/06/28)
Substituted phenacyl molecules are provided and employed to create molecules and polymers/copolymers that exhibit photoresponsiveness. In some instances, the substituted phenacyl molecule is incorporated into the polymer/copolymer backbone, and photoirradiation of the polymer/copolymer causes the substituted phenacyl group to break down and the polymer/copolymer to undergo degradation. In other instances, the substituted phenacyl molecules extend as a side chain from the polymer/copolymer backbone. In yet other instances the substituted phenacyl molecules extend as a side chain from the polymer/copolymer backbone, and a drug or polymer additive is linked to the photoresponsive substituted phenacyl group such that photoirradiation releases the drug or additive. In yet other embodiments the substituted phenacyl molecules extend as a side chain from the polymer/copolymer backbone, and serve to link the polymer/copolymer to another polymer/copolymer backbone, and photoirradiation breaks the links.
Photorelease of incarcerated guests in aqueous solution with phenacyl esters as the trigger
Jagadesan, Pradeepkumar,Da Silva, José P.,Givens, Richard S.,Ramamurthy
, p. 1276 - 1279 (2015/05/20)
We report the clean, efficient photorelease of a series of carboxylic acids embedded in octa acid (OA) host and protected by a p-hydroxyphenacyl cage. A key role is played by the cage by providing hydrophobicity for entry into the OA enclosure and yet readily removable as a photoactivated protecting group for release from the host. The rapid photo-Favorskii rearrangement of the departing chromophore does not react with the host OA but diminishes hydrophobicity of the OA contents, leading to their facile release into the solvent.
Enzyme catalyzed hydroxymethylation of aromatic aldehydes with formaldehyde. Synthesis of hydroxyacetophenones and (S)-benzoins
Demir, Ayhan S.,Ayhan, Peruze,Igdir, A. Cigdem,Duygu, A. Nese
, p. 6509 - 6512 (2007/10/03)
Benzaldehyde lyase from the Pseudomonas Fluorescens catalyzed reaction of aromatic aldehydes with formaldehyde providing 2-hydroxy-1-arylethan-1-one in high yields via an acyloin linkage. Kinetic resolution of rac-benzoins with formaldehyde providing (S)-benzoins and 2-hydroxy-1-arylethan-1-one via C-C bond cleavage and a bond formation reaction.
New phototriggers 9: p-Hydroxyphenacyl as a C-terminal photoremovable protecting group for oligopeptides
Givens, Richard S.,Weber, Joerg F. W.,Conrad II, Peter G.,Orosz, Gyoergy,Donahue, Sarah L.,Thayer, Stanley A.
, p. 2687 - 2697 (2007/10/03)
In our search for a more versatile protecting group that would exhibit fast release rates for peptides, we have designed and developed the p- hydroxyphenacyl (pHP) group as a new photoremovable protecting group. We report the application of this protecting group for the dipeptide Ala-Ala (1) and for the nonapeptide bradykinin (2), two representative peptides that demonstrate C-terminus 'caging' and photorelease. The synthesis of these p- hydroxyphenacyl esters was accomplished in good yields by DBU-catalyzed displacement of bromide from p-hydroxyphenacyl bromide. As in the case of caged γ-amino acids 11 (pHP glu) and 12 (pHP GABA) and caged nucleotide 17 (pHP ATP) reported earlier, irradiations of the p-hydroxyphenacyl esters of 1 and 2 actuate the release of the peptides with rate constants that are consistently greater than 108 s-1 and appearance efficiencies (Φ(app)) that range from 0.1 to 0.3. Release of the substrate is accompanied by a deep-seated rearrangement of the protecting group into the near-UV silent p- hydroxyphenylacetic acid (6). Quenching studies of pHP Ala-Ala (7) with either sodium 2-naphthalenesulfonate or potassium sorbate gave good Stern- Volmer kinetics yielding a rate constant for release of 1.82 x 108 s-1. Quenching of the phosphorescence emission from pHP Ala-Ala (7, E(T) = 70.1 kcal/mol) and pHP GABA (12, E(T) = 68.9 kcal/mol) were also observed. The biological efficacy of bradykinin released from pHP bradykinin (9) was examined on single rat sensory neurons grown in tissue culture. A single 337 nm flash (1 ns) released sufficient bradykinin from the p-hydroxyphenacyl protected nonapeptide to activate cell-surface bradykinin receptors as indicated by a rapid increase in the intracellular calcium concentration. A selective antagonist of type 2 bradykinin receptors blocked the biological response. From these results, it is apparent that flash photolysis of p- hydroxyphenacyl protected peptides provides a powerful tool for the rapid and localized activation of biological receptors.
Mechanism of photosolvolytic rearrangement of p-hydroxyphenacyl esters: Evidence for excited-state intramolecular proton transfer as the primary photochemical step
Zhang, Kai,Corrie, John E. T.,Munasinghe, V. Ranjit N.,Wan, Peter
, p. 5625 - 5632 (2007/10/03)
The photosolvolytic rearrangement of a variety of p-hydroxyphenacyl esters and related compounds 7-16 has been studied in solutions with up to 50% aqueous content, using product studies, triplet quenchers, and nanosecond laser flash photolysis. The p-hydroxyphenacyl moiety has recently been proposed as a new and efficient photoactivated protecting group in aqueous solution. Practical applications have been demonstrated, but much less is known about the mechanism of photoreaction. Our data support a novel mechanism in which the primary photochemical step from the singlet excited state is formal intramolecular proton transfer from the phenolic proton to the carbonyl oxygen of the distal ketone, mediated by solvent water, to generate the corresponding p-quinone methide phototautomer. This reactive intermediate (most likely in its excited state) subsequently expels the carboxylic acid with concerted rearrangement to a spiroketone intermediate, which subsequently leads to the final observed product, p- hydroxyphenylacetic acid. An alternative mechanism is deprotonation of the phenolic proton, loss of the carboxylate, and rearrangement to the spiroketone, all in one concerted primary photochemical step from S1.
