2-furancarboxylic Acid Research Articles

Selective synthesis of 2-furoic acid and 5-hydroxymethyl-2-furancarboxylic acid from bio-based furans by recombinant Escherichia coli cells

Upgradation of bio-based furans into chemicals and biofuels has received great interest recently. In this work, we reported selective synthesis of furan carboxylic acids from the corresponding aldehydes by recombinant Escherichia coli cells expressing 3-succinoylsemialdehyde-pyridine dehydrogenase (SAPDH) from Comamonas testosteroni SC1588. The effects of induction and reaction conditions on whole-cell catalytic oxidation of furfural (FF) were studied. High temperature induction resulted in decreased activities of recombinant cells, likely due to improper protein folding. Nonetheless, recombinant cells induced under high temperature enable the byproduct furfuryl alcohol to be faster re-oxidized into 2-furoic acid (FCA) than those induced under low temperature. So the yield and selectivity of FCA were improved significantly by using high temperature induction, at expense of slightly longer reaction periods. The activities of recombinant cells highly depended on pH. The tolerant levels of this recombinant strain toward FF and 5-hydroxymethylfurfural (HMF) were approximately 100 mM. FCA and 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) were obtained with the yields of 95–98%. FCA of up to 147 mM was produced by a fed-batch strategy, in a quantitative yield. In addition, most aromatic aldehydes tested were transformed into the target carboxylic acids by this biocatalytic method, with the yields up to 100%.

Selective hydrogenolysis of 2-furancarboxylic acid to 5-hydroxyvaleric acid derivatives over supported platinum catalysts

Pt catalysts, especially supported on Al2O3, are effective for hydrogenolysis of 2-furancarboxylic acid to 5-hydroxyvaleric acid (5-HVA) and its derivatives (ester and δ-valerolactone), and the highest yield of 5-HVA derivatives was 62%.

New Compounds of Some Trivalent Lanthanides and Actinides with Furancarboxylic Acid. Synthesis, Structure, and Absorption Spectra of the Complexes [(NH2)3C]2[M(OOCC4H3O)5] (M = La, Ce, Pr, Nd, Tb, Np, Pu, Am)

Eight new compounds of some lanthanides and actinides with furancarboxylate anion were synthesized and studied. Their structure was determined by single crystal X-ray diffraction. All the compounds contain complex anions [M(OOCC4H3O)5]2– in which four of five furancarboxylate anions coordinate the central metal atom in the bidentate fashion via carboxy groups, whereas the fifth anion is bonded to the metal atom only via one O atom of the carboxy group. In all the complexes except the Tb compound the ether oxygen atom of the fifth furancarboxylate anion is also bonded to the metal atom; i.e., a five-membered chelate ring (МОССО) is formed. Such bond is not formed in the Tb compound. Thus, the coordination number of the central atom is 9 in the Tb compound and 10 in the other complexes.

Mutual Influence of Furfural and Furancarboxylic Acids on Their Solubility in Aqueous Solutions: Experiments and Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) Predictions

Furan compounds are of mounting global interest due to their biorenewable nature and their potential to replace petroleum-based compounds as feedstocks in manufacturing. In this work the solubilities of furfural and the furancarboxylic acids 2-furoic acid (FA), 5-formyl-2-furancarboxylic acid (FFA), and 2,5-furandicarboxylic acid (FDCA) in aqueous solutions and organic solvents were investigated experimentally and by modeling with perturbed-chain statistical associating fluid theory (PC-SAFT). The PC-SAFT pure-component parameters of the solutes FA, FFA, and FDCA and one binary parameter between each solute and each solvent were adjusted to fit experimentally determined solubilities of each solute in each organic solvent or in water. Pure-component parameters of furfural were fitted to experimental density data and vapor-pressure data, and a binary interaction parameter was fitted to capture the solubility behavior of furfural in water. Modeling of pH effects enhanced predictions of the mutual influences ...

Chromophores from hexeneuronic acids (HexA): synthesis of model compounds and primary degradation intermediates

Hexeneuronic acid (HexA) is formed under pulping conditions from 4-O-methyl-glucuronic acid residues in xylans by methanol elimination. It is usually removed by an acidic washing treatment (A-stage) within the pulp bleaching sequence. Hexeneuronic acid has long been recognized as a source of color generation in pulps, but the chemical structure of the actual chromophoric compounds remained elusive. We report the synthesis of isotopically (13C) labeled HexA model units carrying a label at any of the six carbon atoms. Confirming pertinent literature accounts, it is shown that HexA forms three primary degradation intermediates, 2-furancarboxylic acid, 5-formyl-2-furancarboxylic acid, and formic acid, under mildly acidic conditions, and their formation mechanism is discussed. 2-Furancarboxylic acid is demonstrated to be deformylation product of 5-formyl-2-furancarboxylic acid. The three primary intermediates are colorless and do not represent chromophores themselves. Their mixture, upon thermal or acidic treatment, gives rise to the same chromophores that are also directly formed from HexA.

Chromophores from hexeneuronic acids: identification of HexA-derived chromophores

Hexeneuronic acids (HexA) have long been known as triggers for discoloration processes in glucuronoxylan-containing cellulosic pulps. They are formed under the conditions of pulping from 4-O-methylglucuronic acid residues, and are removed in an “A stage” along the bleaching sequences, which mainly comprises acidic washing treatments. The chemical structures of HexA-derived chromophoric compounds 4–8, which make up 90% of the HexA-derived chromophores, are reported here for the first time. The compounds are ladder-type, mixed quinoid-aromatic oligomers of the bis(furano)-[1,4]benzoquinone and bis(benzofurano)-[1,4]benzoquinone type. The same chromophoric compounds are generated independently of the starting material, which can be either a) HexA in pulp, b) the HexA model compound methyl 1-13C-4-deoxy-β-L-threo-hex-4-enopyranosiduronic acid (1) or c) a mixture of the primary degradation intermediates of 1, namely 5-formyl-furancarboxylic acid (2) and 2-furancarboxylic acid (3). Isotopic labeling (13C) in combination with NMR spectroscopy and mass spectrometry served for structure elucidation, and final confirmation was provided by X-ray structure analysis. 13C-Isotopic labeling was also used to establish the formation mechanisms, showing all the compounds to be composed of condensed, but otherwise largely intact, 2-carbonylfuran and 2-carbonylfuran-5-carboxylic acid moieties. These results disprove the frequent assumption that HexA-derived or furfural-derived chromophores are linear furanoid polymers, and might have a direct bearing on structure elucidation studies of “humins”, which are formed as dark-colored byproducts in depolymerization of pentosans and hexosans in different biorefinery scenarios.

Evaluation of sublimation enthalpy by thermogravimetry: Analysis of the diffusion effects in the case of methyl and phenyl substituted hydantoins

By using a thermogravimetric analyzer, and applying the Clausius-Clapeyron and Langmuir equations, the enthalpies of sublimation and/or vaporization of a set of organic compounds were obtained without determining the vapor pressures of the compounds. Although the Langmuir equation is strictly valid in vacuum conditions, its validity was tested here both considering and neglecting the diffusional factor. To test and validate these methodologies, molar enthalpies of vaporization or sublimation of a set of ten compounds, whose values have been reported in the literature were determined. The aforementioned compounds are: pyrene, phenanthrene, anthracene, benzoic acid, ferrocene, 2-furancarboxylic acid, 2-thiophenecarboxylic acid, methyl 4-hydroxybenzoate, hydantoin, and 2-thiohydantoin. The values obtained using both methodologies show that, the sublimation enthalpy increases by 0.9–2.5kJmol−1. The methodology that considers the diffusional effect was applied to a group of hydantoines methyl- and phenyl-substituted to determine their enthalpies of sublimation (the group is comprised by 1-methylhydantoin, 5-methylhydantoin, 5,5-diphenylhydantoin, and 5-methyl-5-phenylhydantoin). The enthalpies of these compounds have not been reported so far, and the values show low uncertainty. In addition, the heat capacity at 298.15K, the purity, melting temperature and enthalpy of melting of the compounds studied here were determined by differential scanning calorimetry.

Structural study of Cu(II) complexes with benzo[ b ]furancarboxylic acids

Abstract Four Cu(II) complexes with 2- and 3-benzo[ b ]furancarboxylic acids have been synthesized and characterized using combination of two spectroscopic techniques. These techniques were: ( i ) FTIR and ( ii ) XAFS. FTIR analysis confirmed that complexes were formed and gave insight into identification of possible coordinating groups to the metallic center. XANES analysis indicated that the oxidation state of Cu is +2. EXAFS analysis allowed to identify that the first coordination sphere is formed by 4–5 oxygen atoms with the Cu–O distances around 2 A. Combining these techniques it was possible to structurally describe novel Cu(II) complexes with benzo[ b ]furancarboxylic acids.

A two-step efficient preparation of a renewable dicarboxylic acid monomer 5,5′-[oxybis(methylene)]bis[2-furancarboxylic acid] from d-fructose and its application in polyester synthesis

A renewable monomer 5,5′-[oxybis(methylene)]bis[2-furancarboxylic acid] from d-fructose.

Detection of Bacillus and Stenotrophomonas species growing in an organic acid and endocrine-disrupting chemical-rich environment of distillery spent wash and its phytotoxicity.

Sugarcane molasses-based distillery spent wash (DSW) is well known for its toxicity and complex mixture of various recalcitrant organic pollutants with acidic pH, but the chemical nature of these pollutants is unknown. This study revealed the presence of toxic organic acids (butanedioic acid bis(TMS)ester; 2-hydroxysocaproic acid; benzenepropanoic acid, α-[(TMS)oxy], TMS ester; vanillylpropionic acid, bis(TMS)), and other recalcitrant organic pollutants (2-furancarboxylic acid, 5-[[(TMS)oxy] methyl], TMS ester; benzoic acid 3-methoxy-4-[(TMS)oxy], TMS ester; and tricarballylic acid 3TMS), which are listed as endocrine-disrupting chemicals. In addition, several major heavy metals were detected, including Fe (163.947), Mn (4.556), Zn (2.487), and Ni (1.175mgl-1). Bacterial community analysis by restriction fragment length polymorphism revealed that Bacillus and Stenotrophomonas were dominant autochthonous bacterial communities belonging to the phylum Firmicutes and γ-Proteobacteria, respectively. The presence of Bacillus and Stenotrophomonas species in highly acidic environments indicated its broad range adaptation. These findings indicated that these autochthonous bacterial communities were pioneer taxa for in situ remediation of this hazardous waste during ecological succession. Further, phytotoxicity assay of DSW with Phaseolus mungo L. and Triticum aestivum revealed that T. aestivum was more sensitive than P. mungo L. in the seed germination test. The results of this study may be useful for monitoring and toxicity assessment of sugarcane molasses-based distillery waste at disposal sites.

Catalytic Aerial Oxidation of Biomass‐Derived Furans to Furan Carboxylic Acids in Water over Bimetallic Nickel–Palladium Alloy Nanoparticles

AbstractBimetallic Ni1−xPdx (0.10≤x≤0.75) alloy nanoparticle catalysts were synthesised and successfully employed for the catalytic aerial oxidation of biomass‐derived furans, such as 2‐furfuraldehyde (furfural), 2‐furfuryl alcohol (furfuryl alcohol), 5‐hydroxymethyl‐2‐furfural (5‐HMF), 5‐methyl‐2‐furfural (MF) and 5‐methyl‐2‐furfuryl alcohol (MFA), to selectively afford the corresponding furan carboxylic acids (2‐furoic acid, furan‐2,5‐dicarboxylic acid (FDCA) and 5‐methyl‐2‐furoic acid (MFCA)) in water at 80 °C. Among the studied Ni1−xPdx nanoparticle catalysts, Ni0.90Pd0.10 nanoparticle catalyst outperformed the others, achieving high yields of the corresponding furan carboxylic acid products. The presence of Ni in the Ni1−xPdx nanoparticle catalysts was advantageous, because it not only enhanced the catalytic activity for the facile oxidation of biomass‐derived furans using aerial oxygen to achieve high catalytic turnover, but also provided excellent stability to the Ni0.90Pd0.10 nanoparticle catalyst towards air and water and thus significantly enhanced its recyclability (up to 10 catalytic runs). The experiments revealed that the catalytic oxidation of 5‐HMF proceeded by the initial oxidation of the formyl group to carboxylic acid, and, subsequently, the conversion of alcohol to carboxylic acid via the formyl group to form FDCA. Moreover, the one‐pot direct transformation of fructose to furan carboxylic acid products (such as FDCA) was also achieved by using the Ni0.90Pd0.10 nanoparticle catalyst.

Selective Hydrodeoxygenation of 2-Furancarboxylic Acid to Valeric Acid over Molybdenum-Oxide-Modified Platinum Catalyst

2-Furancarboxylic acid (FCA), produced by oxidation of furfural, is rarely used as a platform molecule. Metal-oxide-supported Pt-MoOx catalysts were effective for hydrodeoxygenation of FCA to valeric acid (VA) in water solvent. The highest VA yield is 51% over Pt-MoOx/TiO2 catalyst under 1.5 MPa H2 at 413 K. Other metal combinations (M-MoOx, M = Rh, Pd, Ru, Ir, Au, none; Pt-M′Ox, M′= V, W, Re, none) showed very low VA yield. This catalyst system was applicable to the hydrodeoxygenation of 2,5-furandicarboxylic acid (FDCA), and adipic acid (AA) was obtained with 21% yield at 473 K.

Furan, phenolic, and heptelidic acid derivatives produced by Aspergillus oryzae.

Eleven compounds, including a new sesquiterpene, were isolated from the culture medium of Aspergillus oryzae incubated with capsaicin. The structure of the new compound was determined to be 1,3,5a,6,7,8,9,9a-octahydro-9-hydroxy-9-(hydroxymethyl)-6-isopropyl-1-oxobenzo[c]oxepine-4- carboxylic acid, a heptelidic acid derivative. In addition, 10 known compounds were identified, namely 5-(hydroxymethyl)-3-furancarboxylic acid (flufuran), 3-hydroxypropanoic acid, 5-(hydroxymethyl)-2- furancarboxylic acid, 2-(4-hydroxyphenyl)-ethanol, 4-hydroxybenzoic acid, vanillic acid, 3,4-dihydroxybenzoic acid, 2-furanol, hydroheptelidic acid, and trichoderonic acid A, using spectroscopic data from nuclear magnetic resonance and electrospray ionization-mass spectroscopy.

LC-MS-Guided Isolation of Penicilfuranone A: A New Antifibrotic Furancarboxylic Acid from the Plant Endophytic Fungus Penicillium sp. sh18.

Penicilfuranone A (1), a novel furancarboxylic acid, and its proposed biosynthetic precursor, gregatin A (2), were isolated from the cultures of the fungus Penicillium sp. sh18 endophytic to the stems of Isodon eriocalyx var. laxiflora guided by HPLC-MS. X-ray crystallography was applied to the structure determination of furancarboxylic acid for the first time, allowing unambiguous assignment of 1. Penicilfuranone A displays a significant antifibrotic effect in activated hepatic stellate cells via negative regulation of transforming growth factor-β (TGF-β)/Smad signaling.

Diorganotin(IV) complexes with 2-furancarboxylic acid hydrazone derivative of benzoylacetone: Synthesis, X-ray structure, antibacterial activity, DNA cleavage and molecular docking

Two new diorganotin(IV) complexes, Me2SnL and Ph2SnL, have been synthesized from the reaction of Me2SnCl2 and Ph2SnCl2 with the hydrazone H2L [H2L = (Furan-2-yl) (5-hydroxy-3-methyl-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl)-methanone] derived from furan-2-carbohydrazide and benzoylacetone. The new compounds have been characterized by elemental and spectroscopic analyses. The crystal structures of the monohydrate form of the ligand and of the Me2SnL derivative have been also determined by X-ray crystallography. Experimental evidences confirm the existence of the hydrazone ligand exclusively in cyclic form in both solution and solid state. On coordination to tin the hydrazone undergoes a ring opening reaction and a doubly deprotonation to act as a tridentate ligand via imine nitrogen and enolic oxygens. The tin atom in the complexes is five coordinate with geometry between square-pyramidal and trigonal-bipyramidal. The in vitro antibacterial activity of ligand and its complexes has been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. The interaction between compounds with bacterial DNA was also studied by molecular docking. Our findings indicate that diphenyltin(IV) complex, by binding to DNA via minor groove to TATA sequence in genes upstream, has good activities along with the standard antibacterial drugs. Our agarose-gel electrophoresis experiments show that the ligand exert DNA cleavage, while Me2SnL and Ph2SnL did not.

Synthesis of carbohydrate biomass-based furanic compounds bearing epoxide end group(s) and evaluation of their feasibility as adhesives

Current issues of energy and environment prompt us to replace fossil-based resources with renewable and sustainable ones. In this regard, carbohydrate biomass photosynthesized from atmospheric carbon dioxide attracts much attention due to its abundance and availability. Recently, furanic compounds that can be derived from carbohydrate biomass are highlighted as promising substitutes for aromatic compounds that are totally dependent on petroleum reforming processes. In this article, we report on several carbohydrate biomass-based furanic compounds as alternatives to petroleum-based adhesives. Furanic compounds bearing epoxide end group(s) were synthesized from renewable and sustainable carbohydrate biomass-based compounds (>70% yields). Another bis-epoxy furanic compound with a mimetic structure of bisphenol A (BPA) was also synthesized from xylose-derived 2-furan carboxylic acid and acetone (39% overall yield). In particular, epoxy groups were efficiently introduced to the hydroxymethyl functionality attached by furanic cores under the bi-phasic solvent system using phase transfer catalysis. Cationic photo-curing kinetic profiles of synthetic compounds were investigated in terms of heat flow integrals using photo-DSC. It was found that their halftime values (t 1/2), representing curing rates, ranged from 0.54 to 1.15 min when irradiated with 40 mW/cm2 UV light. When synthetic furanic compounds functionalized by epoxide group(s) were used for bonding polycarbonate by cationic photo-curing, we noted that tensile-shear strength of PC joints bonded with biomass-based furan mono-epoxide having furan ring was greater (4.7 MPa) than that of joints bonded with petrochemical-based phenyl glycidyl ether having phenyl ring (2.6 MPa). When bonded with di-epoxide functionalized furan di-epoxide, tensile-shear strength of PC joint was 3.5 MPa after photo-curing for 3 min at 40 °C. However, bis-furan di-epoxide (bFdE), the mimetic compound of BPA showed lower tensile-shear strength (approximately 1 MPa) due to structural features of bFdE, such as rigidity and hydrophobic property.

Discovery and Evaluation of Thiazinoquinones as Anti-Protozoal Agents

Pure compound screening has identified the dioxothiazino-quinoline-quinone ascidian metabolite ascidiathiazone A (2) to be a moderate growth inhibitor of Trypanosoma brucei rhodesiense (IC50 3.1 μM) and Plasmodium falciparum (K1 dual drug resistant strain) (IC50 3.3 μM) while exhibiting low levels of cytotoxicity (L6, IC50 167 μM). A series of C-7 amide and Δ2(3) analogues were prepared that explored the influence of lipophilicity and oxidation state on observed anti-protozoal activity and selectivity. Little variation in anti-malarial potency was observed (IC50 0.62–6.5 μM), and no correlation was apparent between anti-malarial and anti-T. brucei activity. Phenethylamide 7e and Δ2(3)-glycine analogue 8k exhibited similar anti-Pf activity to 2 but with slightly enhanced selectivity (SI 72 and 93, respectively), while Δ2(3)-phenethylamide 8e (IC50 0.67 μM, SI 78) exhibited improved potency and selectivity towards T. brucei rhodesiense compared to the natural product hit. A second series of analogues were prepared that replaced the quinoline ring of 2 with benzofuran or benzothiophene moieties. While esters 10a/10b and 15 were once again found to exhibit cytotoxicity, carboxylic acid analogues exhibited potent anti-Pf activity (IC50 0.34–0.035 μM) combined with excellent selectivity (SI 560–4000). In vivo evaluation of a furan carboxylic acid analogue against P. berghei was undertaken, demonstrating 85.7% and 47% reductions in parasitaemia with ip or oral dosing respectively.

Optimization and Kinetics of Furfural Oxidation to Furoic Acid Over Alum-impregnated Activated Alumina

In the present investigation, oxidation of furfural was carried out using alum-impregnated activated alumina, which led to the formation of 2-furancarboxylic acid (furoic acid). Operational parameters such as catalytic ratio were varied from 1 to 9%, temperature from 40 to 70°C, initial concentration from 0.1 to 0.5 m and time from 0.5–7.5 h, and were optimized using Box–Behnken design. The Fisher F-value of 55.10 confirmed that the second-order regression model used for prediction of results was satisfactory. By using the reaction scheme proposed, rate constants at various reaction temperatures were determined. Activation energy and frequency factor corresponding to the reaction were also calculated.

Electrochemical synthesis and structural studies of zinc(II) complexes with derivatives of benzo[b]furancarboxylic acids

Three novel zinc complexes with benzo[b]furan-carboxylic acids were obtained. The elemental and thermal analyses, and IR spectroscopy were used for basic characterization of compounds. The Zn(II) coordination geometry was studied by X-ray absorption spectroscopy. In microcrystalline powders for all complexes the cation is penta-coordinated (ZnO5) with the Zn–O distances equal to ca. 2Å, as determined by extended X-ray absorption fine structure. For recrystallized Zn(II) complex 1 (with 7-acetyl-6-methoxy-3-methyl-benzo[b]furan-2-carboxylic acid) crystal structure was determined by X-ray crystallography, and this analysis indicated a distorted polyhedron around the cation in which one of the Zn–O distances is above 2.5Å.

An interpenetrating HA/G/CS biomimic hydrogel via Diels–Alder click chemistry for cartilage tissue engineering

In order to mimic the natural cartilage extracellular matrix, a novel biological degradable interpenetrating network hydrogel was synthesized from the gelatin (G), hyaluronic acid (HA) and chondroitin sulfate (CS) by Diels–Alder “click” chemistry. HA was modified with furylamine and G was modified with furancarboxylic acid respectively. 1H NMR spectra and elemental analysis showed that the substitution degrees of HA-furan and G-furan were 71.5% and 44.5%. Then the hydrogels were finally synthesized by cross-linking furan-modified HA and G derivatives with dimaleimide poly(ethylene glycol) (MAL-PEG-MAL). The mechanical and degradation properties of the hydrogels could be tuned simply through varying the molar ratio between furan and maleimide. Rheological, mechanical and degradation studies demonstrated that the Diels–Alder “click” chemistry is an efficient method for preparing high performance biological interpenetrating hydrogels. This biomimic hydrogel with improved mechanical properties could have great potential applications in cartilage tissue engineering.