24979-70-2Relevant academic research and scientific papers
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).
Monitoring hydroxycinnamic acid decarboxylation by lactic acid bacteria using high-throughput UV-Vis spectroscopy
García-Cano, Israel,Giusti, M. Monica,Jiménez-Flores, Rafael,Miyagusuku-Cruzado, Gonzalo,Rocha-Mendoza, Diana
, (2020)
Hydroxycinnamic acid (HCA) decarboxylation by lactic acid bacteria (LAB) results in the production of 4-vinylplenols with great impact on the sensorial characteristics of foods. The determination of LAB decarboxylating capabilities is key for optimal strain selection for food production. The activity of LAB strains from the Ohio State University-Parker Endowed Chair (OSU-PECh) collection potentially capable of synthesizing phenolic acid decarboxylase was evaluated after incubation with HCAs for 36 h at 32 °C. A high-throughput method for monitoring HCAs decarboxylation was developed based on hypsochromic shifts at pH 1.0. Out of 22 strains evaluated, only Enterococcus mundtii, Lactobacillus plantarum and Pediococcus pentosaceus were capable of decarboxylating all p-coumaric, caffeic and ferulic acids. Other strains only decarboxylated p-coumaric and caffeic acid (6), only p-coumaric acid (2) or only caffeic acid (1), while 10 strains did not decarboxylate any HCA. p-Coumaric acid had the highest conversion efficiency, followed by caffeic acid and lastly ferulic acid. Results were confirmed by HPLC-DAD-ESI-MS analyses, showing the conversion of HCAs into their 4-vinylphenol derivatives. This work can help improve the sensory characteristics of HCA-rich foods where fermentation with LAB was used during processing.
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.
Facile synthesis and characterization of highly branched polystyrene by self-condensing atom transfer radical polymerization
Lee, Jun Hyup
, p. 46 - 51 (2017)
To simply prepare hyperbranched polystyrene with dendritic structure for optical and electronic applications, the copper-mediated self-condensing atom transfer radical polymerization of 4-(2-bromopropionyl)oxy styrene has been attempted. Given the unequal reactivity of two propagating species owing to different substituents which stabilize radicals, the influence of polymerization conditions on the structure of dendritic polystyrene were investigated. Higher polymerization temperature leaded to the lower functionality of Br in the branched polystyrene due to HBr elimination. As the catalyst to monomer ratio increased, the degree of branching of the prepared polystyrene was enhanced by increasing the reaction chance of the less stabilized propagating site.
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.
Microbial transformations of p-Coumaric acid by Bacillus megaterium and Curvularia lunata
Torres y Torres,Rosazza
, p. 1408 - 1414 (2001)
p-Coumaric acid (1) is an abundant phenolic natural product that exhibits both chemoprotectant and antioxidant properties. Microbial transformation screening studies showed that 1 was converted to 4-vinylphenol (4), 4-hydroxybenzoic acid (2), caffeic acid (5), protocatechuic acid (6), and other unidentified metabolites over 144 h. 4-Vinylphenol (4) and its dimer, (2R,2S)-4-(2,3-dihydro-5-hyroxy-2-benzofuranyl) phenol (11), were produced by Bacillus megaterium, and 5-[(E)-2-carboxyethenyl]-2,3-dihydro-2-(4hydroxyphenyl)-3- benzofurancarboxylic acid (15) and 4-hydroxybenzoic acid (2) were produced by Curvularia lunata. On the basis of deuterium-labeling experiments, B. megaterium catalyzes the nonoxidative enzymatic tautomerization of 1 to a vinylogous β-keto acid intermediate that decarboxylates to 4. The presence of peroxidase and laccase activities in C. lunata extracts suggests that these enzymes may be involved in one-electron, p-coumaric acid dimerization in this organism.
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.
Tetrazolation of side chains and anhydrous conductivity in a hydrophobic polymer
Ricks-Laskoski, Holly L.,Chaloux, Brian L.,Deese, Stephen M.,Laskoski, Matthew,Miller, Joel B.,Buckley, Mary A.,Baldwin, Jeffrey W.,Hickner, Michael A.,Saunders, Kaitlin M.,Christensen, Caroline M.
, p. 4243 - 4250 (2014)
1H-Tetrazoles possess the lowest pKa within the azole family of nitrogen-containing heterocycles, making them attractive amphoteric moieties for anhydrous proton conduction. The synthesis of a styrenic, random coil polymer with pendent C-substituted 1H-tetrazoles is described in detail. This facile route results in a polymer containing free proton-bearing tetrazoles, limits side reactions, and proceeds using low polarity, halogenated solvents (e.g., 1,2-dichlorobenzene or chlorobenzene), which improve solubility during tetrazole cyclization. The resulting polymer, when probed by NMR spectroscopy and elemental analysis, had no measurable salt content, ensuring accurate proton conductivity measurements. Utilizing interdigitated electrodes (IDEs) in conjunction with electrochemical impedance spectroscopy (EIS), undoped anhydrous proton conductivities were measured to be as high as 10-5 S cm -1 at 120 °C. This weakly acidic, 1H-tetrazole-bearing polymer is thermally stable to 210 °C, possesses two distinct glass transitions (Tg) at 49 and 74 °C, and exhibits surprisingly low water uptake, despite its acidic and amphoteric nature. Reduction of Tgs, achieved by synthesis of low molecular weight poly(4-vinylphenol) via acid polymerization, shows a minimal dependence of anhydrous proton conductivity on backbone motion.
