2-furancarboxylic Acid Research Articles

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.

Two coordination modes around the Cu(II) cations in complexes with benzo[b]furancarboxylic acids

Three Cu(II) complexes with derivatives of the benzo[b]furancarboxylic acid have been synthesized and characterized by the elemental and thermal analyses, and IR spectroscopy. The geometry of metal–ligand interaction for all compounds has been described using X-ray absorption spectroscopy and for one of them by X-ray crystallography. Two mononuclear Cu(II) complexes, with 7-acetyl-5-bromo-6-hydroxy-3-methylbenzo[b]furan-2-carboxylic and 6-acetyl-5-hydroxy-2-methylbenzo[b]furan-3-carboxylic acids, exhibit a tetra-fold coordination, CuO4. The Cu(II) cation in crystals with 7-acetyl-6-methoxy-3-methyl-benzo[b]furan-2-carboxylic acid is penta-coordinated; the bridging COO− groups and ethanol molecule stabilize the dinuclear center Cu2O10. The powdered form of this complex is based on the Cu2O8 units, indicating the absence of the ethanol molecules.

N, N- bis (2-CHLOROETHYL)AMIDES AND N, N- bis (2-CHLOROETHYL)HYDRAZIDES OF CARBOXYLIC ACIDS OF THE FURAN SERIES

Reaction of N, N-bis(2-chloroethyl)amine hydrochloride with chloroanhydrides of carboxylic acids of the furan series, in chloroform in the presence of pyridine gives N, N-bis(2-chloroethyl)amides of furan carboxylic acid, furylacrylic acid, 5-nitrofuran carboxylic acid, and 5-nitrofurylacrylic acid. N, N-bis(2-chloroethyl)hydrazides of furan carboxylic acid, furyl carboxylic acid, 5-nitrofuran carboxylic acid, and 5-nitrofurylacrylic acid were obtained in 78–88% yields by reacting N, N-bis(2-chloroethyl)hydrazine hydrochloride with the chloroanhydrides of the appropriate acids in chloroform in the presence of pyridine. The last two hydrazides were prepared in 31 % and 56 % yield, respectively, using anhydrous sodium acetate in place of pyridine. Authors: B. V. Kurgan, S. A. Giller, A. A. Gruze. English Translation in Chemistry of Heterocyclic Compounds , 1965, 1 (1), pp 5-7 http://link.springer.com/article/10.1007/BF01168908

Derivatives of benzo[b]furan. Part II. Structural studies of derivatives of 2- and 3-benzo[b]furancarboxylic acids

The selected derivatives of the 2- and 3-benzo[b]furancarboxylic acids were synthesized and their structures were studied using the X-ray crystallography and the computational methods. The monocarboxylic acids (1–3) crystallize as dimers stabilized by the O–H···O intermolecular hydrogen bonds. Moreover, intramolecular hydrogen bonds are formed between the OH and C(=O)CH3 groups, substituted to the aromatic ring (2–4). In the crystal structures of 1–4, weak C–H···O, C–H···π, and C–H···Br interactions stabilize the three-dimensional packing of molecules. The crystalline sodium complex of 1 has the stoichiometry [Na + ·1A − ·1B]·1C, thus, the asymmetric unit contains three different moieties of 1. In this complex, the Na+ cation is hexacoordinated having a strongly distorted tetragonal bipyramidal polyhedron. For each molecule 1–4, several conformers were obtained in the gas phase. It was achieved by the rotations of substituents [COOR and/or C(=O)CH3, where R = H, CH3] with respect to the rigid benzo[b]furan system. As indicated by the quantum-chemical calculations, the solid-state conformers for 3 and 4 (3-benzo[b]furancarboxylic acid derivatives) are the most stable ones. In contrast, the solid-state conformers of the 2-benzo[b]furancarboxylic acid derivatives (1, 2) have the energies higher than the lowest energy conformer by 1.23 and 0.69 kcal/mol, respectively. It seems that intermolecular contacts in the crystal influence on the orientation of substituents, and the conformers observed in the sodium complex of 1 provide evidence of such flexibility. Hirshfeld surface for a pair of molecules 2A/2B (bromo-derivative).

Furan- and selenophene-2-carboxylato derivatives of dimolybdenum and ditungsten (MM): a comparison of their chemical and photophysical properties

From the reactions between M(2)(T(i)PB)(4), where T(i)PB = 2,4,6-triisopropylbenzoate and two equivalents each of 2-furan carboxylic acid, FuCO(2)H, and 2-selenophene carboxylic acid, SpCO(2)H in toluene, the new compounds trans-M(2)(T(i)PB)(2)(O(2)CFu)(2) (1a M = Mo, 2a M = W) and trans-M(2)(T(i)PB)(2)(O(2)CSp)(2) (1b M = Mo, 2b M = W) were formed. These new compounds have been characterized by (1)H NMR, steady-state UV-Vis-NIR absorption and emission spectroscopy, cyclic and differential pulse voltammetry, and fs and ns transient absorption spectroscopy. The compound Mo(2)(T(i)PB)(2)(O(2)CSp)(2) (1b) has been characterized by single crystal X-ray crystallography. These data are compared with those previously reported for related 2-thiophene carboxylate derivatives: M(2)(T(i)PB)(2)(O(2)CTh)(2). The physico-chemical data correlate well with electronic structure calculations performed on model compounds. All compounds have detectible S(1) photoexcited states with lifetimes that vary from ∼5 ps to < 1 ps. The molybdenum compounds have T(1) states with microsecond lifetimes that are assigned as MMδδ* whereas the T(1) states for tungsten are (3)MLCT with lifetimes on the order of nanoseconds. In all cases, shorter lifetimes were seen in complexes containing heavier atoms.

Effect of Oxygen on Volatile and Sensory Characteristics of Cabernet Sauvignon during Secondary Shelf Life

The oxidation of Cabernet Sauvignon wines during secondary shelf life was studied by headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-quadrupole mass spectrometry (GC-qMS) and sensory tests, with the support of multivariate statistical analyses such as OPLS-DA loading plot and PCA score plot. Four different oxidation conditions were established during a 1-week secondary shelf life. Samples collected on a regular basis were analyzed to determine the changes of volatile chemicals, with sensory characteristics evaluated through pattern recognition models. During secondary shelf life the separation among collected samples depended on the degree of oxidation in wine. Isoamyl acetate, ethyl decanoate, nonanoic acid, n-decanoic acid, undecanoic acid, 2-furancarboxylic acid, dodecanoic acid, and phenylacetaldehyde were determined to be associated with the oxidation of the wine. PCA sensory evaluation revealed that least oxidized wine and fresh wine was well-separated from more oxidized wines, demonstrating that sensory characteristics of less oxidized wines tend toward "fruity", "citrous", and "sweetness", while those of more oxidized wines are positively correlated with "animal", "bitterness", and "dairy". The study also demonstrates that OPLS-DA and PCA are very useful statistical tools for the understanding of wine oxidation.

Synthesis of phosphonomethylated acid chlorides, alcohols, and aldehydes of the furan series

Diethoxyphosphorylmethyl derivatives of furancarboxylic acids react with thionyl chloride in the presence of DMF to form the corresponding acid chlorides. Compounds synthesized were reduced with sodium borohydride in the DMF-dioxane medium to give hydroxymethyl compounds. Obtained phosphorylated alcohols were oxidized to aldehydes by chromium trioxide-pyridine complex in methylene chloride. The diethoxyphosphorylmethyl group remains untouched in all these transformations. A series of phosphorylated acid chlorides, alcohols, and aldehydes including all six versions of mutual location of phosphorus-containing substituent and another functional group in the furan ring was synthesized. It is established that 2,3- and 3,2-(diethoxyphosphorylmethyl)(chlorocarbonyl)furans in the course of vacuum distillation undergo cyclization to 4,5(2,3-furo)- and 4,5(3,2-furo)-1,2-oxaphosphorines.

(N-Isocyanimino)triphenylphosphorane-Mediated, One-Pot, Efficient Synthesis of Sterically Congested 1,1,1-Trifluoro-2-(5-aryl-1,3,4-oxadiazol-2-yl)-2-propanol Derivatives via Intramolecular Aza-Wittig Reaction

Reactions of (N-isocyanimino)triphenylphosphorane with 1,1,1-trifluoroacetone in the presence of aromatic (or heteroaromatic) carboxylic acids (3-methylbenzoic acid, 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, 2-furancarboxylic acid, and 2-thiophenecarboxylic acid) proceed smoothly at room temperature and in neutral conditions to afford sterically congested 1,1,1-trifluoro-2-(5-aryl-1,3,4-oxadiazol-2-yl)-2-propanol derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions, and no side reactions were observed. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Synthesis, characterization, and in vitro antimicrobial evaluation of hydrazone and bishydrazone derivatives of isatin

A new series of hydrazone and bishydrazone derivatives was synthesized starting from adipic dihydrazide, oxalyl dihydrazide, 4-hydroxybenzhydrazide, 2-furancarboxylic acid hydrazide, acetohydrazide, 4-pyridinecarboxylic acid hydrazide, and isatin. The chemical structures were confirmed by means of 1H-NMR, UV, and IR spectral data and elemental analysis. The synthesized compounds were evaluated in vitro as antimicrobial agents against representative strains of Gram-positive (clinical strains of Staphylococcus saprophyticus, Bacillus cereus, Enterococcus faesium), Gram-negative bacteria (clinical strains of Klebsiella pneumonia, Escherichia coli, Serratia marcescens, Pseudomonas aeruginosa, Shigella dysenteriae, Salmonella typhi), and antifungal agent against Candida albicans (clinical isolated) by the minimal inhibitory concentration (MIC) method. MIC was defined as the lowest concentration of compound inhibiting the growth of each strain. All the bacteria and fungi studied were screened against some antibiotics and their chemical zone diameters compared.

Synthesis and evaluation of some novel dibenzo[ b, d]furan carboxylic acids as potential anti-diabetic agents

A series of novel dibenzo[ b, d]furan mono-carboxylic acid derivatives were synthesized, characterized and evaluated for their ability to inhibit Protein Tyrosine Phosphatase 1B (PTP1B) in vitro in order to use them as potential anti-diabetic agents. Structure–activity relationship study led to the identification of potent compound 5E which inhibited PTP1B with IC 50 value of 82 ± 0.43 nM. Compound 5E was screened in vivo as drug candidate for anti-diabetic activity using rosiglitazone maleate as the standard. Compound 5E showed significant reduction in body weight, fed-state whole blood glucose (WBG), fasting WBG, plasma glucose and plasma cholesterol levels and non-significant reduction in fasting plasma triglyceride levels in ob/ ob mice.

ChemInform Abstract: Utilization of 2‐Benzo[b]furan Carboxylic Acid Hydrazide in the Synthesis of 1,3,4‐Oxadiazole Derivatives.

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Utilization of 2‐benzo[b]furan carboxylic acid hydrazide in the synthesis of 1,3,4‐oxadiazole derivatives

Abstract magnified imageIn this study, the synthesis of series of 2‐benzo[b]furan‐substituted 1,3,4‐oxadiazole derivatives using readily available 2‐benzo[b]furan carboxylic acid hydrazide as starting material has been investigated. J. Heterocyclic Chem., (2009).

Synthesis of Condensed Heteroaromatic Compounds by Palladium-Catalyzed Oxidative Coupling of Heteroarene Carboxylic Acids with Alkynes

The palladium-catalyzed oxidative coupling of indole-3-carboxylic acids with alkynes effectively proceeds in a 1:2 manner accompanied by decarboxylation to produce the corresponding 1,2,3,4-tetrasubstituted carbazoles, some of which exhibit solid-state fluorescence. Pyrrole-, benzofuran-, and furancarboxylic acids also undergo the decarboxylative coupling to afford highly substituted indole, dibenzofuran, and benzofuran derivatives, respectively.

Trichopyrone and Other Constituents from the Marine Sponge-Derived Fungus Trichoderma sp.

The fungus Trichoderma viride was isolated from the Caribbean sponge Agelas dispar, which was collected from waters around the island of Dominica. Its EtOAc extract, exhibiting mild radical scavenging properties, was mass cultivated and found to produce a new pyranone derivative, trichopyrone (1), and ten compounds, namely four sorbicillinoid polyketide derivatives, trichodermanone A-D (2-5), two hexaketide derivatives, rezishanone (6) and vertinolide (7), three known dodecaketides, trichodimerol (8), bislongiquinolide (trichotetronine, 9), and bisvertinol (10), as well as 2-furancarboxylic acid (11). The structures of all compounds were determined by interpretation of their spectroscopic data (1D and 2D NMR, MS, UV and IR). The biological activities of all isolates were evaluated in a series of bioassays (radical scavenging, antioxidant, antimicrobial, inhibition of HIV-1 RT). The majority had very weak or no effects in the applied test systems.

Chaetominedione, a new tyrosine kinase inhibitor isolated from the algicolous marine fungus Chaetomium sp.

A marine fungal isolate, identified as Chaetomium sp., was cultivated and found to produce a novel benzonaphthyridinedione derivative, chaetominedione ( 1). In addition to the known fungal metabolites, 2-furancarboxylic acid ( 2) and 5-(hydroxymethyl)-2-furancarboxylic acid ( 3) were obtained. The structures of all the compounds were determined based on extensive spectroscopic measurements (1D and 2D NMR, MS, UV, and IR). The total extract and compound 1 had significant inhibitory activity toward p56 lck tyrosine kinase (18.7% and 93.6% enzyme inhibition at 200 μg/mL, respectively).

An anomalous linear dichroic effect in the polarized IR spectra of 2-furancarboxylic acid crystals: Proton transfer induced by co-operative interactions involving hydrogen bonds

The polarized IR spectra of the hydrogen bond systems were studied in crystals of 2-furancarboxylic acid C 4H 3O–COOH as well as in crystals of its deuterium-bonded derivative. The spectra were measured by a transmission method at room temperature and at 77 K. Theoretical analysis of the results concerned the linear dichroic effects, the H/D isotopic and the temperature effects observed in the solid-state IR spectra at the frequency ranges of the ν O–H and the ν O–D bands, respectively. The main spectral properties of the crystals can be quantitatively interpreted in terms of the “ strong-coupling” theory for a hydrogen bond dimer model. This model explains satisfactorily not only the two-branch structure of the ν O–H and the ν O–D bands, the temperature-induced evolution of the crystalline spectra, but also the basic linear dichroic effects observed in the band frequency ranges. A vibronic mechanism, responsible for promotion of the symmetry-forbidden transition in the IR and for the excitation of the totally symmetric proton stretching vibrations in centrosymmetric hydrogen bond dimers was also taken into the account. An excess of fine linear dichroic effects, accompanying the splitting of the spectral lines in the crystalline spectra, appeared for the crystal with only one dimer in a unit cell. This fact suggests that the existence of a specific co-operative interaction effect in the lattice, depending on the stimulated rearrangement of the proton positions in the hydrogen bond dimers, occurring in the nearest surrounding of an individual dimer in the lattice. Therefore, regardless of the published X-ray P 1 ¯ space-symmetry of the lattice, the effective unit cell for explaining the crystalline spectra behaved as if it contained two nonequivalent dimers. Re-examination of the crystal X-ray structure supported the hypothesis concerning the lattice transformation predicted by the IR spectroscopic studies.

Thermochemical and thermophysical study of 2-thiophenecarboxylic acid hydrazide and 2-furancarboxylic acid hydrazide

The standard ( p ∘ = 0.1 MPa) molar energies of combustion, Δ c U m ∘ , for the crystalline 2-thiophenecarboxylic acid hydrazide and 2-furancarboxylic acid hydrazide were determined, at the temperature of 298.15 K, by rotating bomb and static bomb combustion calorimetry, respectively. For these compounds, the standard molar enthalpies of sublimation, Δ cr g H m ∘ , at T = 298.15 K, were derived by the Clausius–Clapeyron equation, from the temperature dependence of the vapour pressures of these compounds, measured by the Knudsen effusion mass-loss technique. The results were as follows: - Δ c U m ∘ ( cr ) / ( kJ · mol - 1 ) - Δ f H m ∘ ( cr ) / ( kJ · mol - 1 ) Δ cr g H m ∘ / ( kJ · mol - 1 ) 2-Thiophenecarboxylic acid hydrazide 3359.4 ± 1.1 63.9 ± 1.3 113.3 ± 0.5 2-Furancarboxylic acid hydrazide 2620.8 ± 0.6 205.5 ± 0.9 99.0 ± 0.7 These values were used to derive the standard molar enthalpies of formation of the title compounds in their gaseous phases and the results are discussed in terms of energetic effects of the introduction of the –CONHNH 2 group in the thiophene and furan rings. Using estimated values for the heat capacity differences between the gas and the crystal phases of the studied compounds, the standard ( p ∘ = 0.1 MPa) molar enthalpies, entropies, and Gibbs energies of sublimation, at T = 298.15 K, were derived.

Aminomethyl derivatives of furancarboxylic acids in the Paal-Knorr reaction

Aminomethyl derivatives of furancarboxylic acids react with 1,4-dicarbonyl compounds under Paal-Knorr reaction conditions to form the pyrrole ring. It is found that α-aminomethyl derivatives of furancarboxylic acids react faster than their β analogs. The carboxy group adjacent to the aminomethyl fragment decelerates the process.

Reactions of alkyl (halomethyl)furancarboxylates with hexamethylenetetramine

All isomers of (aminomethyl)furancarboxylic acids were prepared by the Delepine reaction from alkyl (halomethyl)furancarboxylates. Treatment of the initially formed quaternary salt with an ethanolic HCl solution yielded the salts of the corresponding unstable amino acid esters. A procedure for their purification to a high degree of purity was developed. Hydrolysis of the crude esters yielded stable amino acid salts.