24979-70-2Relevant articles and documents
Obtaining 4-vinylphenols by decarboxylation of natural 4-hydroxycinnamic acids under microwave irradiation
Bernini, Roberta,Mincione, Enrico,Barontini, Maurizio,Provenzano, Gianfranco,Setti, Leonardo
, p. 9663 - 9667 (2007)
4-Vinylphenols, useful compounds for industrial applications, were obtained by decarboxylation of 4-hydroxycinnamic acids under microwave irradiation in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as base and basic aluminum oxide as solid support. The reactions were fast (15-30 min). The selective extraction of the final products with ethyl acetate avoids chromatographic purifications. The conversions are quantitative and the yields are satisfactory. Only the unstable 4-vinylcatechol was obtained in moderate yield. This procedure was successfully extended to a natural sample of ferulic acid extracted from wheat bran to get the corresponding 4-vinylguaiacol, a FEMA GRAS (Flavor and Extract Manufacturer's Association; General Regarded as Safe) approved flavoring agent.
Phosphorus- And Sulfur-Containing High-Refractive-Index Polymers with High Tg and Transparency Derived from a Bio-Based Aldehyde
Fang, Linxuan,Sun, Jing,Chen, Xiaoyao,Tao, Yangqing,Zhou, Junfeng,Wang, Caiyun,Fang, Qiang
, p. 125 - 131 (2020)
Two flexible and colorless polymers are synthesized based on a phosphorus-containing derivative of a bio-based aromatic aldehyde (4-hydroxybenzaldehyde) by a thiol-ene reaction. Thanks to the high polarizability of phosphorus and sulfur atoms, two polymers display refractive index (n) values of 1.721 and 1.698 at 546 nm, respectively. These data are much higher than those of polyphosphonates (below 1.65) and are comparable to those of polyphosphazenes with undesirable halogens (1.664-1.755). Moreover, both the polymers (TVP-TH1 and TVP-TH2) exhibit a transmittance of above 88% in the wavelength range from 550 to 2000 nm and a transmittance of about 0% in the UV region, indicating their potential application as transparent coatings for hindering the ultraviolet ray and infrared transmitting materials. In particular, these phosphorous-sulfide polymers display good thermostability with a glass transition temperature (Tg) of above 130 °C and 5% weight loss temperature (T5d) of over 310 °C. These results imply that new phosphorous-sulfide polymers are very suitable as encapsulation resins for light-emitting diodes (LEDs) and optical materials and as antireflective coatings and microlenses for the image sensors of complementary metal oxide semiconductors (CMOSs).
4-Vinylphenyl Glycidyl Ether: Synthesis, RAFT Polymerization, and Postpolymerization Modifications with Alcohols
McLeod, David C.,Tsarevsky, Nicolay V.
, p. 1135 - 1142 (2016)
4-Vinylphenyl glycidyl ether (4VPGE), an epoxide-containing styrenic monomer, was synthesized and then polymerized in a controlled fashion under reversible addition-fragmentation chain-transfer (RAFT) polymerization conditions using butyl 1-phenylethyl trithiocarbonate as the chain-transfer agent. The high degree of chain-end functionalization of the produced polymers was confirmed by chain extension reactions with styrene that afforded well-defined block copolymers. Phenyl glycidyl ether was utilized as a model compound to identify the optimal reaction conditions for alcoholysis of the glycidyl moiety using BF3 as a Lewis acid catalyst, and postpolymerization modifications were subsequently carried out on the epoxide groups of poly4VPGE with a library of structurally diverse alcohols to yield a number of β-hydroxy ether-functionalized polymers.
Novel Amination and 1,2-Amino,hydro-Elimination between 2,3-Diketopyrido[4,3,2-de]quinolines and Primary Amino Compounds
Ding, Qizhu,Lown
, p. 7965 - 7972 (1999)
A novel animation and 1,2-amino,hydro-elimination reaction occurs between 2,3-diketopyrido[4,3,2-de]quinoline (1, 2) and amino compounds which include α-amino acids and peptides which contain a primary amino group. The amino group undergoes nucleophilic addition to the double bond between C3a and C4 in 2,3-diketopyrido[4,3,2-de]quinoline to form a 3a,4-dihydro-2,3-diketopyrido-[4,3,2-de]quinoline. This dihydro intermediate is immediately oxidized by ambient air to produce the more stable aromatic system, 4-(N-alkyl or aryl)-2,3-diketopyrido[4,3,2-de]quinoline (5-12). In the cases of aliphatic amines bearing a β-proton in THF or chloroform, this 4-(N-alkyl)-2,3-diketopyrido[4,3,2-de]quinoline undergoes a 1,2-amino,hydro-elimination reaction to eliminate an alkene and produce the 4-amino-2,3-diketopyrido[4,3,2-de]quinoline (13, 14). In the cases of α-amino acids in aqueous solution, the 4-(N-alkyl)-2,3-diketopyrido[4,3,2-de]quinoline undergoes an amino-transferring reaction, via a mechanism similar to the action of pyridoxal, to form the 4-amino-2,3-diketopyrido[4,3,2-de]quinolme (13) and the α-keto acid. 2,3-Diketopyrido[4,3,2-de]quinoline (1) can also react with the peptide which contains a primary amino group to form the 2,3-diketopyrido-[4,3,2-de]quinoline-peptide conjugate. This novel amination-elimination reaction may underlie the marked cytotoxic potency of the 2,3-diketopyrido[4,3,2-de]quinolines (1 and 2). As inorganic amino compounds, hydroxylamine and hydrazine can also undergo the nucleophilic addition to 2,3-diketopyrido[4,3,2-de]quinoline (1, 2) to produce 4-amino-2,3-diketopyrido[4,3,2-de]quinoline (13, 14) which includes a elimination reaction between C4 and α-nitrogen.
Two-photon induced isomerization through a cyaninic molecular antenna in azo compounds
Villatoro, Emmanuel,Mu?oz-Rugeles, Leonardo,Durán-Hernández, Jesús,Salcido-Santacruz, Bernardo,Esturau-Escofet, Nuria,López-Cortés, Jose G.,Ortega-Alfaro, M. Carmen,Peón, Jorge
, p. 3123 - 3126 (2021)
We present a new design for non-linear optically responsive molecules based on a modular scheme where a polymethinic antenna section with important two-photon absorption properties is bonded to an isomerizable actuator section composed of a stilbenyl-azopyrrole unit. Upon two photon excitation, energy migration from the antenna-localized second singlet excited state to the stilbenyl-azopyrrole section allows for efficient indirect excitation and phototransformation of this actuator.
Characterization of the p-coumaric acid decarboxylase from Lactobacillus plantarum CECT 748T
Rodriguez, Hector,Landete, Jose Maria,Curiel, Jose Antonio,De Las Rivas, Blanca,Mancheno, Jose Miguel,Munoz, Rosario
, p. 3068 - 3072 (2008)
It was previously reported that cell cultures from Lactobacillus plantarum CECT 748T were able to decarboxylate phenolic acids, such as p-coumaric, m-coumaric, caffeic, ferulic, gallic, and protocatechuic acid. The p-coumaric acid decarboxylase (PDC) from this strain has been overexpressed and purified. This PDC differs at its C-terminal end when compared to the previously reported PDC from L. plantarum LPCHL2. Because the C-terminal region of PDC is involved in enzymatic activity, especially in substrate activity, it was decided to biochemically characterize the PDC from L. plantarum CECT 748T. Contrarily to L. plantarum LPCHL2 PDC, the recombinant PDC from L. plantarum CECT 748T is a heat-labile enzyme, showing optimal activity at 22°C. This PDC is able to decarboxylate exclusively the hydroxycinnamic acids p-coumaric, caffeic, and ferulic acids. Kinetic analysis showed that the enzyme has a 14-fold higher KM value for p-coumaric and caffeic acids than for ferulic acid. PDC catalyzes the formation of the corresponding 4-vinyl derivatives (vinylphenol and vinylguaiacol) from p-coumaric and ferulic acids, respectively, which are valuable food additives that have been approved as flavoring agents. The biochemical characteristics showed by L. plantarum PDC should be taken into account for its potential use in the food-processing industry.
Antioxidant properties of 4-vinyl derivatives of hydroxycinnamic acids
Terpinc, Petra,Polak, Toma?,?egatin, Nata?a,Hanzlowsky, Andrej,Ulrih, Nata?a Poklar,Abramovi?, Helena
, p. 62 - 69 (2011)
The compounds 4-vinylphenol (4-VP), 4-vinylguaiacol (4-VG), 4-vinylsyringol (4-VS) and 4-vinylcatechol (4-VC) were prepared by thermal decarboxylation of the corresponding hydroxycinnamic acids p-coumaric, ferulic, sinapic and caffeic acid, respectively. For confirmation of the synthesised products LC-MS followed by NMR analysis was used. To evaluate their antioxidant potential, their reducing power and efficiency in scavenging the alkylperoxyl radical generated in an emulsion system, the 2,2-diphenyl-1-picrylhydrazyl (DPPH ·) radical and the superoxide anion radical (O2-) were determined. All tested 4-vinyl derivatives revealed weaker antioxidant activity in a homogeneous polar medium than the corresponding phenolic acids. In the emulsion system the activity for 4-vinyl derivatives was higher than was the activity of their corresponding phenolic acids, with 4-VG as the most active among the tested phenolic compounds.
3D-Printed Phenacrylate Decarboxylase Flow Reactors for the Chemoenzymatic Synthesis of 4-Hydroxystilbene
Peng, Martin,Mittmann, Esther,Wenger, Lukas,Hubbuch, Jürgen,Engqvist, Martin K. M.,Niemeyer, Christof M.,Rabe, Kersten S.
, p. 15998 - 16001 (2019)
Continuous flow systems for chemical synthesis are becoming a major focus in organic chemistry and there is a growing interest in the integration of biocatalysts due to their high regio- and stereoselectivity. Methods established for 3D bioprinting enable the fast and simple production of agarose-based modules for biocatalytic reactors if thermally stable enzymes are available. We report here on the characterization of four different cofactor-free phenacrylate decarboxylase enzymes suitable for the production of 4-vinylphenol and test their applicability for the encapsulation and direct 3D printing of disk-shaped agarose-based modules that can be used for compartmentalized flow microreactors. Using the most active and stable phenacrylate decarboxylase from Enterobacter spec. in a setup with four parallel reactors and a subsequent palladium(II) acetate-catalysed Heck reaction, 4-hydroxystilbene was synthesized from p-coumaric acid with a total yield of 14.7 % on a milligram scale. We believe that, due to the convenient direct immobilization of any thermostable enzyme and straightforward tuning of the reaction sequence by stacking of modules with different catalytic activities, this simple process will facilitate the establishment and use of cascade reactions and will therefore be of great advantage for many research approaches.
Aromatic vs. aliphatic hyperbranched polyphosphoesters as flame retardants in epoxy resins
Markwart, Jens C.,Battig, Alexander,Velencoso, Maria M.,Pollok, Dennis,Schartel, Bernhard,Wurm, Frederik R.
, (2019)
The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, we present novel halogen-free aromatic and aliphatic hyperbranched polyphosphoesters (hbPPEs), which were synthesized by olefin metathesis polymerization and investigated them as a FR in epoxy resins. We compare their efficiency (aliphatic vs. aromatic) and further assess the differences between the monomeric compounds and the hbPPEs. The decomposition and vaporizing behavior of a compound is an important factor in its flame-retardant behavior, but also the interaction with the pyrolyzing matrix has a significant influence on the performance. Therefore, the challenge in designing a FR is to optimize the chemical structure and its decomposition pathway to the matrix, with regards to time and temperature. This behavior becomes obvious in this study, and explains the superior gas phase activity of the aliphatic FRs.
Rapid biosynthesis of phenolic glycosides and their derivatives from biomass-derived hydroxycinnamates
Zhao, Mingtao,Hong, Xulin,Abdullah,Yao, Ruilian,Xiao, Yi
, p. 838 - 847 (2021/02/09)
Biomass-derived hydroxycinnamates (mainly includingp-coumaric acid and ferulic acid), which are natural sources of aromatic compounds, are highly underutilized resources. There is a need to upgrade them to make them economically feasible. Value-added phenolic glycosides and their derivatives, both belonging to a class of plant aromatic natural products, are widely used in the nutraceutical, pharmaceutical, and cosmetic industries. However, their complex aromatic structures make their efficient biosynthesis a challenging process. To overcome this issue, we created three novel synthetic cascades for the biosynthesis of phenolic glycosides (gastrodin, arbutin, and salidroside) and their derivatives (hydroquinone, tyrosol, hydroxytyrosol, and homovanillyl alcohol) fromp-coumaric acid and ferulic acid. Moreover, because the biomass-derived hydroxycinnamates directly provided aromatic units, the cascades enabled efficient biosynthesis. We achieved substantially high production rates (up to or above 100-fold enhancement) relative to the glucose-based biosynthesis. Given the ubiquity of the aromatic structure in natural products, the use of biomass-derived aromatics should facilitate the rapid biosynthesis of numerous aromatic natural products.
Copper(ii)-catalyzed protoboration of allenes in aqueous media and open air
Nekvinda, Jan,Santos, Webster L.,Snead, Russell F.
supporting information, p. 14925 - 14931 (2021/09/04)
A method has been developed for the facile Cu(ii)-catalyzed protoboration of monosubstituted allenes in aqueous media under atmospheric conditions. The reaction occurs site selectively, favoring internal alkene protoboration to afford 1,1-disubstituted vinylboronic acid derivatives (up to 93?:?7) with modest to good yields. The method has been applied to a variety of phenylallene derivatives as well as alkyl-substituted allenes. This journal is
