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Furfural is an attractive bio‐based platform chemical that has many derivatives of commercial interest. Herein, we show that the selectivity of the direct furfural reduction can be steered from 2‐methylfuran and 2‐methyltetrahydrofuran to furfuryl alcohol and tetrahydrofurfuryl alcohol by varying the ratio of formic acid and sodium formate. These reagents take the role of terminal reductants in the disclosed heterogeneous Pd‐catalysed process. We report the development and optimisation of the reaction conditions for three different products directly from furfural: 2‐methyltetrahydrofuran, tetrahydrofurfuryl alcohol and 2‐methylfuran which were obtained in 59 %, 46 %, and 63 % selectivity, respectively. Furthermore, the protocol uses commercially available Pd/Al2O3 as catalyst and the formic acid and sodium formate can be obtained from biogenous sources. [ABSTRACT FROM AUTHOR]

Most of the previously reported fluorescent organic probes for cancer cell and tumor imaging have significant limitations including chemical toxicity, structural instability, low Stokes shift value, and the inability for selective accumulations in tumors during in vivo imaging. To overcome the mentioned challenges, we synthesized the fluorescent probes with protected polar functional groups to enhance the non‐toxicity nature and increase the selectivity toward tumors. In addition, the structural rigidity of the fluorescent probes was increased by embedding aromatic rings in the probe structure. This issue enables us to obtain ultrabright cell images due to enhanced fluorescence quantum yield (ΦFL) values. After synthesis and spectral characterizations, the applicability of two furan‐based and imidazole‐based fluorescent probes (abbreviated as DCPEF and DBPPI, respectively) was investigated for ultrabright in vitro and in vivo imaging of cancer cells. The probe DCPEF shows the ΦFL value of 0.946 and the Stocks shift of 86 nm. In addition, probe DBPPI offers the ΦFL value of 0.400 and a Stocks shift of 150 nm. The MTT colorimetric cytotoxicity assay showed that probe DCPEF has minimal effects against HT‐29 (cancer) and Vero (normal) cells. The probe DCPEF produced ultrabright fluorescence images from HT‐29 cells. In addition, in vivo imaging of cancer cells showed that probe DCPEF selectively accumulates in the 4T1 tumor in mice. The spectral and chemical stability, minimal cytotoxicity, significant Stokes shift, and high degree of selectivity for tumor cells during in vivo imaging make DCPEF an appropriate candidate to be used as a standard probe for cancer cell imaging. [ABSTRACT FROM AUTHOR]

[Display omitted] The N-doped carbon material obtained by thermochemical conversion of a polycondensation product of a liquid fraction of humins (a waste product of plant biomass conversion into furan derivatives) with the nitrogen-containing crosslinking component melamine was investigated as a support in Pt/C electrocatalysts for the oxygen reduction reaction. [ABSTRACT FROM AUTHOR]

N-Furfuryl allylamines react with a broad range of isocyanates, isothiocyanates, isoselenocyanates with the formation of a 3a,6-epoxyisoindole core in one synthetic stage. The interaction sequence involves two consecutive steps: the nucleophilic addition reaction and the intramolecular Diels–Alder furane (IMDAF) reaction. The scope and limitations of the proposed method were thoroughly investigated, and it was revealed that the key [4+2] cycloaddition step proceeds through an exo-transition state, giving rise to the exclusive formation of a single diastereomer of the target heterocycle. Dynamic temperature NMR analysis allowed to fully investigating a case of coalescence of NMR signals and determined the coalescence temperature during the transition O → Se. The antimicrobial properties of the obtained compounds against sensitive strains of yeast Candida albicans, fungus Aspergillus niger and bacteria including Staphylococcus aureus, Micrococcus luteus, Pseudomonas fluorescens were identified. [ABSTRACT FROM AUTHOR]

As global industries move toward sustainability, the search for alternatives to current petroleum‐based polymer products is becoming necessary. Bio‐based epoxy resins have emerged as a sustainable alternative to petroleum‐based epoxy resins. Commonly, furan derivatives, carbohydrates, cardanol, and lignin are commercially utilized with bio‐based curing agents to form crosslinked structures. In recent years, epoxidized vegetable oils have gathered significant attention as sustainable bio‐based materials for epoxy resin. Vegetable oils have an abundance of unsaturation sites, leading to epoxy‐functionalized molecules. This review provides various materials, synthesis methods, properties, and applications of vegetable oil‐based epoxy resins. [ABSTRACT FROM AUTHOR]

A novel photocatalytic [4+2] cyclization strategy was developed for the transformation of biomass furan into a unique and cage-like oxabicyclo[2.2.1]heptene molecular skeleton. This strategy also enabled a significant and efficient cyclization of furan with acrylate. It provides access to the common core shared by a range of biologically active natural products and medicines, such as cantharidin, palasonin, and OBHSA. [ABSTRACT FROM AUTHOR]

Iridium catalyzed electrochemical coupling of naphthols with acrylates for the syntheses of naphtho[1,8‐bc]furan derivatives are herein reported. Ir‐catalyzed electrochemical C−H annulation is accomplished within a supportive catalysis manifold, paving the way for electrooxidative C−H acrylation via weak O‐coordination. The merge of iridium catalysts and electric current not only minimizes the need for a stoichiometric amount of chemical oxidants but also confirms broad reaction compatibility with a variety of electronically and sterically diverse substrates. This utility provides a valuable method for producing a wide range of naphtho[1,8‐bc]furan derivatives in good to moderate yields. [ABSTRACT FROM AUTHOR]

A practical and effective palladium-catalyzed C–H activation/alkene insertion/annulation has been reported for the synthesis of furans and cyclopropanes from cyclic 1,3-diketones or 1,3-indandione and diverse alkenes, resulting in moderate to good yields. This protocol demonstrates excellent selectivity and is well-compatible with a wide range of alkene substrates, exhibiting exceptional regioselectivities, high efficiency, and good functional group tolerance. [ABSTRACT FROM AUTHOR]

Given the enormous safety risks and environmental pollution that restrict the green development of isocyanate produced by phosgene reactions, we propose a new green and intrinsically safe route for synthesizing diisocyanates containing the furan ring from 5-hydroxymethylfurfural. In this work, the following novel reactions have been systematically investigated, including synthesizing a new compound methyl furan-2,5-dimethylene dicarbamate (FDC) using 2,5-bis(aminomethyl)furan (BAF) and dimethyl carbonate (DMC), the selective hydrogenation of FDC to a new compound methyl tetrahydrofuran-2,5-dimethylene dicarbamate (THFDC), and FDC and THFDC catalytic decomposition to produce corresponding furan-2,5-dimethylene diisocyanate (FDI) and tetrahydrofuran-2,5-dimethylene diisocyanate (THFDI). The results showed that CH3ONa could effectively catalyze the synthesis of FDC from BAF and DMC, and the separation yield of FDC was 98.1% under mild conditions including a nBAF : nDMC ratio of 1 : 10 at 70 °C for 4 h. CH3ONa can be recycled up to four times with high stability. A 0.5% Pd/γ-Al2O3 catalyst with low Pd loading was prepared, and it showed high catalytic activity and stability for FDC hydrogenation to THFDC, with a THFDC yield of 99.9% at 100 °C, 2 MPa H2 and 1 h, and the catalyst could be reused after simple treatment with ethanol. The structure–activity relationship of supported Pd catalysts was studied. The conditions for the thermal decomposition reactions of FDC and THFDC were optimized, resulting in FDI and THFDI yields as high as 89.6% and 92.8%, respectively. Owing to the urgent need for raw materials sustainability and environmental friendliness, the brand-new safe pathway for synthesizing FDI and THFDI was constructed, significantly improving the competitiveness of the non-phosgene method in preparing bio-based isocyanate. [ABSTRACT FROM AUTHOR]

Herin, we demonstrate the synthesis and catalytic efficacy of Fe3O4@SiO2-Amine-DAB/Py-CuCl2 nanocomposite as a novel catalyst in synthesizing various 2,3,5-triaryl furans via oxidative cyclization of aryl ketones with styrenes and oxidation of sulfides to sulfoxides under eco-friendly conditions. Our catalytic system accommodates a broad substrate scope, encompassing aryl ketones, styrenes, and aryl sulfides with both withdrawing and donating groups on the ring, yielding target products with high yields. Additionally, the catalyst exhibits notable reusability, maintaining stable efficiency over seven runs, as confirmed by VSM, TEM, and ICP-OES analyses, which validate the structural integrity of Fe3O4@SiO2-Amine-DAB/Py-CuCl2 even after eight recovery cycles. The developed Fe3O4@SiO2-Amine-DAB/Py-CuCl2 nanocomposite catalyst, demonstrating its efficiency and reusability in synthesizing 2,3,5-triaryl furans and diaryl sulfoxides under environmentally friendly conditions, which contributes significantly to the advancement of green catalysis methodologies. [ABSTRACT FROM AUTHOR]

A concise and efficient synthetic protocol for the synthesis of furan-based bis-stilbene derivatives (BPBFCz1) was described, which is a very promising organic laser dye. Starting with 4,4'-diethynylbiphenyl, BPBFCz1 was prepared with a total yield of 40% through a three-step classical reaction of Sonogashira Coupling, intramolecular cyclization of 2-alkynyl phenol, and Buchwald Hartwig cross-coupling. The crystal structure of BPBFCz1 was presented for the first time. The synthesis strategy was applied to the synthesis of other three materials with similar structure and the yields of 28.6–36.6% were obtained. [ABSTRACT FROM AUTHOR]

Diabetes Mellitus (DM) is a chronic disease that occurs when the pancreas does not produce enough insulin, or the body cannot use insulin effectively. Type 2 DM treatment can be done using antidiabetic drugs, but the continuous use of synthetic drugs will cause side effects. Empirically, the people of Nias Indonesia use palm juice (Arenga pinnata Merr.) as an antidiabetic, which can reduce blood glucose levels. This study aimed to find the active compounds in palm juice that can potentially be an antidiabetic type 2 using an in silico approach. The methods used were toxicity screening, profile pharmacokinetics, drug scanning, docking, and molecular dynamics simulation. Screening, molecular docking, and molecular dynamics of 30 compounds generated from pyrazine and furan revealed that two compounds, PF 16 and PF 30, can bind to receptors and produce lower ∆G values than metformin HCl. Molecular dynamics simulation results using the MM-GBSA calculation method showed that the PF 16 compound was more selective than the 2PDY (aldose reductase) with a value of -39.23 kcal/mol, while compound PF 30 was more selective to 1Z89 (aldose reductase) with a value of -7.36 kcal/mol. It can be concluded that the level of affinity of the PF 30 compound to the 1Z89 receptor and the PF 16 compound to the 2PDY were predicted to have the potential as antidiabetic (DM type 2).

A protocol for the synthesis of trisubstituted furans via phosphoric acid‐catalyzed regioselective cascade cyclization/amination of para‐quinone methides (p‐QMs) with β‐ketodinitriles has been disclosed for the first time. Various kinds of p‐QMs and β‐ketodinitriles can effectively produce the desired polysubstituted furan derivatives in 64–95% yields, demonstrating high atomic economy and their application in the construction of polysubstituted furan heterocycles. Preliminary biological activity assay suggests that these furans have potential anticancer activities. [ABSTRACT FROM AUTHOR]

2,5-Furandicarboxylic acid (FDCA) is an important bio-derived monomer to produce poly(ethylene 2,5- furandicarboxylate) (PEF), known for its superior gas barrier properties in comparison with the widely used poly(ethylene terephthalate) (PET). Among the various synthesis routes to FDCA, electrocatalytic oxidation of furan precursors is an attractive choice due to its great energy efficiency with hydrogen as the coproduct. With the aim of efficiently producing FDCA and H2, we employed an electrodeposition and subsequent oxidation method to synthesize nickel--copper alloy catalysts for the electrolysis of 2,5-bis (hydroxymethyl)furan (BHMF). The optimized Ni7Cu3 catalyst exhibited a remarkable FDCA yield of 99.8% at nearly complete conversion of BHMF. In situ Raman spectroscopy revealed that Ni3+ species served as the active sites during the BHMF oxidation. Surface copper oxide facilitated the maintenance of the high valence state of Ni3+ during the reaction. The superior electrical conductivity of Cu compared to Ni boosted the transport of electrons from reactant molecules through the catalytic layer and collector to the outer circuit. The addition of nickel not only enhanced the catalytic activity of copper foam but also contributed to slowing down of the leaching of copper during electrolysis. This work provides novel insights into the mechanistic elucidation of alloy catalysts for biomass electrooxidation. [ABSTRACT FROM AUTHOR]

Natural products and their semi‐synthetic derivatives undoubtedly constitute an important source of therapeutic agents. Their importance lies in their own origin and evolution, since they have great chemical diversity, biochemical specificity, and pharmacological properties. Currently, there is a renewed interest in the development of methodologies capable of efficiently modifying the chemical structure of these bioactive platforms. In this work, the photoderivatization of the diterpene solidagenone was performed using a complexity‐to‐diversity‐oriented approach. By exploring [2+2]‐photocycloaddition, photoinduced‐hydrogen abstraction, and photoxygenation reactions, a set of solidagenone derivatives was obtained, showing different ring fusions, side chain rearrangements, and modifications of the original furan ring's substitution pattern. The derivatives obtained were characterised by NMR methodologies. To evaluate the structural diversity of the labdane‐derived compounds, their physicochemical properties, structural similarity, and chemical space were analysed. These results suggest that photochemical reactions are a useful tool for performing ring distortion transformations, generating derivatives of natural compounds with wide diversity, structural complexity, and with potential biological properties. [ABSTRACT FROM AUTHOR]

Cu(II) Complex of tetradentate Schiff-base supported on silica [Cu(II) Schiffbase@-SiO2] catalyzed reactions of aryl aldehydes with carbonyl compounds (dimedon/4-hydroxy coumarin/1,3-cyclohexadion) and malononitrile in aqueous media (H2O:EtOH) to preparation of benzo[b]pyrans and 3,4-dihydropyrano[c] chromanes. Also, using this nanocatalyst, 2-(5-substituted phenyl)furan2-carboxaldehyde derivatives with carbonyl compounds (dimedon/4-hydroxy coumarin/1,3-cyclohexadion) and malononitrile gave novel tetrahydrobenzo [b]pyran and 3,4-dihydropyrano[c]chromane derivatives in high yields in H2O: EtOH under reflux conditions. The key advantages of this catalytic systems are the formation of novel products, high yields (78%–93%), short reaction time, broad substrate scope, environmentally friendly reaction conditions and also, without need to column chromatography for purification. Furthermore, the nanocatalyst can be reused six times without losing catalytic activity. [ABSTRACT FROM AUTHOR]

A gram‐scale synthesis of calix[5]‐ and calix[6]furan was achieved by a one‐pot condensation of furan and acetone followed by stepwise separation of calix[n]furans (n=4–6) using size‐selective precipitation procedures. Calix[n]furans were converted to cyclic polyketones and then to ethylene‐bridged cyclic isopyrazoles. The conformational analysis of the cyclic furan, polyketone, and isopyrazole macrocycles was performed based on their single crystal structures, providing important structural insights for intermolecular interactions. The scalable synthetic procedures for larger calix[n]furans and their derivatives would contribute to further coordination and host‐guest chemistry using their cavities. [ABSTRACT FROM AUTHOR]

Diabetes Mellitus (DM) is a chronic disease that occurs when the pancreas does not produce enough insulin, or the body cannot use insulin effectively. Type 2 DM treatment can be done using antidiabetic drugs, but the continuous use of synthetic drugs will cause side effects. Empirically, the people of Nias Indonesia use palm juice (Arenga pinnata Merr.) as an antidiabetic, which can reduce blood glucose levels. This study aimed to find the active compounds in palm juice that can potentially be an antidiabetic type 2 using an in silico approach. The methods used were toxicity screening, profile pharmacokinetics, drug scanning, docking, and molecular dynamics simulation. Screening, molecular docking, and molecular dynamics of 30 compounds generated from pyrazine and furan revealed that two compounds, PF 16 and PF 30, can bind to receptors and produce lower ΔG values than metformin HCl. Molecular dynamics simulation results using the MM-GBSA calculation method showed that the PF 16 compound was more selective to the 2PDY (aldose reductase) with a value of -39.23 kcal/mol, while compound PF 30 was more selective to 1Z89 (aldose reductase) with a value of -7.36 kcal/mol. It can be concluded that the level of affinity of the PF 30 compound to the 1Z89 receptor and the PF 16 compound to the 2PDY were predicted to have the potential as antidiabetic (DM type 2). [ABSTRACT FROM AUTHOR]

An unusual benzofuran synthesis from 2,6-disubstituted phenols and alkynyl sulfoxides is disclosed. Various highly substituted benzofurans were synthesized via the charge-accelerated [3,3]-sigmatropic rearrangement and subsequent substituent migration. Multiaryl-substituted benzofurans and fully substituted benzofurans were prepared on the basis of the unique reaction mechanism. [ABSTRACT FROM AUTHOR]

Lochmann–Schlosser base, a stoichiometric combination of nBuLi and KOtBu, is commonly used as a superbase for deprotonating a wide range of organic compounds. In the present study, we report that catalytic potassium hexamethyldisilazide (KHMDS) exhibits higher catalytic activity than KOtBu for successive bromine–metal exchanges. Accordingly, 1–10 mol% of KHMDS dramatically enhances halogen dance reactions to introduce various electrophiles to bromopyridine, bromoimidazole, bromothiophene, bromofuran, and bromobenzene derivatives with the bromo group translocated from the original position. A dual catalytic cycle is proposed to explain the ultrafast bromine transfer. [ABSTRACT FROM AUTHOR]

Recently, catalytic valorization of biomass‐derived furans has received growing interest. 5‐Aminomethyl‐2‐furancarboxylic acid (AMFC), a furan amino acid, holds great promise in the aeras of polymer and pharmaceutical, but its synthesis remains limited. In this work, we report a chemobiocatalytic route toward AMFC by combining laccase‐TEMPO system and recombinant Escherichia coli (named E. coli_TAF) harboring ω‐transaminase (TA), L‐alanine dehydrogenase (L‐AlaDH) and formate dehydrogenase (FDH), starting from 5‐hydroxymethylfurfural (HMF). In the cascade, HMF is oxidized into 5‐formyl‐2‐furancarboxylic acid (FFCA) by laccase‐TEMPO system, and then the resulting intermediate is converted into AMFC by E. coli_TAF via transamination with cheap ammonium formate instead of costly organic amine donors, theoretically generating H2O and CO2 as by‐products. The tandem process was run in a one‐pot twostep manner, affording AMFC with approximately 81 % yield, together with 10 % 2,5‐furandicarboxylic acid (FDCA) as by‐product. In addition, the scale‐up production of AMFC was demonstrated, with 0.41 g/L h productivity and 8.6 g/L titer. This work may pave the way for green manufacturing of the furan‐containing amino acid. [ABSTRACT FROM AUTHOR]

The effective and mild [4+1] annulation of ninhydrin-derived MBH carbonates with α,β-unsaturated ketones has been developed, providing a wide range of multisubstituted furans in high yields (up to 90%) with excellent β-regioselectivities. In contrast, the polysubstituted cyclopentenes bearing dispiro-bisindanedione motifs were obtained via classical [3+2] annulations by employing ninhydrin-derived MBH carbonates with 2-arylidene-1,3-indandiones under the same catalytic conditions. Furthermore, the structures of two kinds of cycloadducts were straightforwardly confirmed through X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

2,4‐dimethylfuran has a rare disubstitution pattern in the five‐membered heterocyclic furan ring that is highly interesting chemically but challenging to access synthetically. We present a heterogeneously catalysed route to synthesise 2,4‐dimethylfuran from commonly available 2,5‐dimethylfuran using a zeolite packed‐bed flow reactor. As supported by DFT calculations, the reaction occurs inside the zeolite channels, where the acid sites catalyse proton transfer followed by migration of a methyl group. The zeotype Ga‐silicate (MFI type) appears superior to an aluminium‐containing ZSM‐5 by demonstrating higher selectivities and slower catalyst deactivation. This work provides new opportunities for the continuous valorisation of bio‐feedstock molecules in the perspective of the emerging biorefinery era. [ABSTRACT FROM AUTHOR]

Methyl 5-aminomethylfuran-2-carboxylates reacted with methylamine to give 5-aminomethylN-methylfuran-2-carboxamides, and their hydrolysis afforded the corresponding carboxylic acids. The reaction of methyl 5-aminomethylfuran-2-carboxylates with hydrazine hydrate produced hydrazides which were acylated with benzoyl or 2-furoyl chloride and then subjected to heterocyclization to obtain furan derivatives containing a 1,3,4-oxadiazole ring. The target products were also synthesized in one step by reacting 5-aminomethylfuran-2-carbohydrazides with acid chlorides in the presence of phosphoryl chloride. [ABSTRACT FROM AUTHOR]

Alongside fermentable sugars, weak acids, and furan derivatives, lignocellulosic hydrolysates contain non-negligible amounts of lignin-derived aromatic compounds. The biological funnel of lignin offers a new strategy for the "natural" production of protocatechuic acid (PCA). Herein, Pseudomonas putida KT2440 was engineered to produce PCA from lignin-derived monomers in hydrolysates by knocking out protocatechuate 3,4-dioxygenase and overexpressing vanillate-O-demethylase endogenously, while acetic acid was used for cell growth. The sugar catabolism was further blocked to prevent the loss of fermentable sugar. Using the engineered strain, a total of 253.88 mg/L of PCA was obtained with a yield of 70.85% from corncob hydrolysate 1. The highest titer of 433.72 mg/L of PCA was achieved using corncob hydrolysate 2 without any additional nutrients. This study highlights the potential ability of engineered strains to address the challenges of PCA production from lignocellulosic hydrolysate, providing novel insights into the utilization of hydrolysates. [ABSTRACT FROM AUTHOR]

The current work focused on the intermediate pyrolysis of Bambara Groundnut Shells (BGS-G1), Sweet Sorghum Stalk (SSS), and Shea Nutshells (SNS). These feedstocks are readily available as wastes or by-products from industrial and agricultural activities. The thermo-gravimetric analysis of the biomass samples exhibited decomposition and devolatilization potentials in the temperature range of 110–650°C. The kinetic modelling resulted in the activation energy of BGS G1 being the lowest as 20.43 kJ/mol and SNS as the highest 24.89 kJ/mol among the three biomass samples. Intermediate pyrolysis was conducted in a vertical tube reactor at a temperature of 600°C, with nitrogen flow at 10 ml/min and heating rate ≥ 33.0℃/min. The yield of pyrolysis bio-oil was 38.0 ± 6.4, 44.2 ± 6, and 39.7 ± 5.2 wt.% for BGS-G1, SSS, and SNS, respectively. The HHV of bio-oil varied as 23.7 ± 1.8, 23.8 ± 1.8, to 26.5 ± 2.0 MJ/kg for BGS-G1 SSS and SNS respectively. The biochar recorded the lowest HHV for BGS-G1 as 18.8 ± 1.2 MJ/kg and the highest for SNS as 26.4 ± 1.8 MJ/kg. The FTIR of bio-oil revealed significant functional groups, and GC-MS (Gas Chromatography and Mass Spectrometry) analysis categorized the compounds in bio-oils as ketones, furans, phenolics, acids, phenols and benzene derivatives. The physicochemical analysis of the feedstocks and the products (bio-oil and biochar) showed their potential for bioenergy and biochemical (green chemicals) production. [ABSTRACT FROM AUTHOR]

Enynones and enynals represent donor‐type carbene precursors that efficiently form furyl metal carbenes via a catalytic intramolecular 5‐exo‐dig cyclization and rearrangement cascade, in a 100 % atom‐economical manner, using various metals. These furyl metal carbenes have been successfully utilized in numerous carbene reactions, including metal carbene X−H insertion, cyclopropanations, metathesis, and cross‐coupling, demonstrating a broad reaction scope and efficiency in constructing highly functionalized furans. Recent years have witnessed significant advancements in transformations involving furyl metal carbenes, especially in asymmetric carbene insertion reactions, domino reactions involving zwitterionic intermediates, various rearrangement strategies, and their application in synthesizing functional materials and drug candidates. In this review, we summarize recent progress in furyl metal carbene reactions generated from enynones and enynals, focusing on the synthesis of highly functionalized furans. [ABSTRACT FROM AUTHOR]

Jiuqu is one of the important raw materials for brewing Chinese rice wine (Huangjiu), often known as the "bone of wine". In this study, the microbial community and flavor substances of Jiuqu made with different amounts of shiitake mushroom (Lentinula edodes) were investigated through high-throughput sequencing technology and headspace gas chromatography–ion migration spectroscopy (HS-GC-IMS), using traditional wheat yeast as a control. The results showed that 1593 genera and 5507 species were identified among the four types of yeast, with Aspergillus and Paecilomyces being the most dominant microorganisms at the genus level. Carbohydrate, coenzyme, and amino acid metabolism may be the main metabolic processes of the dominant microorganisms in Jiuqu. In terms of flavor, a total of 79 volatile substance monomers and some dimers were detected from four types of Jiuqu raw materials, with the main substances being 12 aldehydes, 19 ketones, 13 alcohols, 19 esters, 4 olefins, 1 acid, 3 ethers, 4 furans, 1 pyrazine, 1 pyridine, 1 triethylamine, and 1 thiazole. The correlation results indicate that Aspergillus, Lactobacillus, and Vibrio correlate significantly with the volatile flavor compounds unique to shiitake mushrooms and also have a positive effect on alcohol, esters, and furans. These results could shed light on the selection of Lentinula edodes as a fermentation starter for Huangjiu in the Qinba Mountain area. [ABSTRACT FROM AUTHOR]

A new flavonoid (bunge A) (1), a new sesquiterpene (bunge B) (8), a new furan derivative (bunge C) (12) and a new alkenoic acid (bunge D) (14), together with ten known ones [four flavonoids (2, 3, 4, 5), two phenylpropanoids (6, 7), three sesquiterpenes (9, 10, 11) and one lactone (13)] were isolated from the fruits of Prunus humilis Bunge [Cerasus humilis (Bunge) Sokolov]. Their structures were elucidated based on extensive spectroscopic analysis (including HR-ESI-MS and NMR) and comparison with previously published data. All compounds were evaluated for cytotoxic activity against three human tumour cell lines. Compound 3 and 4 showed weak antiproliferative activities against hepatocarcinoma cell HepG-2 at the concentration of 100 μM, which the inhibition rates were 55.34 ± 0.29 and 45.52 ± 0.37, respectively. And other compounds had almost no cytotoxic activity against the three tumour cell lines in vitro. [ABSTRACT FROM AUTHOR]

Cellulose-derived 5-hydroxymethylfurfural (HMF) is a key platform in biomass valorisation, with a market value exceeding USD 60 million. Its redox reformed products are highly desirable, serving as the precursors of various sustainable polymers, fuels and fine chemicals. By decoupling the photocatalytic redox species, HMF can be upgraded under different routes, via hydroxymethyl and/or aldehyde groups, to diverse value-added products. Here, we focus on the latest heterogeneous photocatalysis for converting HMF to 2,5-diformylfuran (DFF), 2,5-furandicarboxylic acid (FDCA) and 2,5-bis(hydroxymethyl)furan (BHMF). Particular attention is paid to the effect of aerobic/anaerobic conditions on active species, redox pathways and derived products. Under aerobic conditions, reactive oxygen species (˙O2−, 1O2 and ˙OOH) generated from photogenerated holes/electrons and molecular oxygen act as the active species, driving the oxidation of HMF to DFF and FDCA via oxidative dehydrogenation or insertion reactions, along with H2O2 generation as the side product. In comparison, photogenerated holes can directly oxidise HMF to DFF coupled with electron-involved H2 production. In aerobic conditions, HMF can be hydrogenated to BHMF using solvent protons or in situ generated H2 enabled by decoupling and activation of charge carriers and hydrogenation sites. Challenges and fundamental insights associated with anerobic and anaerobic approaches for selective redox transformations of HMF are discussed, which pave the way for the design of highly efficient and net-zero solar biorefineries. [ABSTRACT FROM AUTHOR]

Chain elongation of unprotected carbohydrates in water under mild conditions remains a challenge both in chemical and biochemical synthesis. The Knoevenagel addition or condensation enables transformations to bioactive scaffolds for pharmaceutical and agrochemical compounds. Unfortunately, the catalysts in use for these transformations often reduce the green metrics of the transformations. Here, we use in situ NMR visualizations to explore the prospective use of natural catalysts for the synthesis of triple- and quadruple-functionalized furan- or dihydrofuran-derivatives from glucose and malononitrile. The dihydrofuran derivatives are formed as kinetic, major intermediates in the pathway to furan derivatives when using naturally abundant MgO or bio-sourced chitosan and N-Methyl-d-glucamine (meglumine) as the catalysts in water. Both catalyst loading, solvent composition and pH can be adapted to populate dihydrofurans with four substituents by slowing down their further reactions. Higher temperatures and higher pH values favor the formation of triple-functionalized furans over quadruple-substituted dihydrofurans, which may be bicyclic or monocyclic. Compared to more traditional catalysts, nature-sourced options offer more sustainable options that emulate natural processes. Visualization with in situ NMR contributes to streamlining the development of cheap and environmentally benign procedures for carbohydrate chain elongation. [ABSTRACT FROM AUTHOR]

Unsaturated ketones of the furan series have been synthesized by the aldol–crotonic condensation of furfural with some unsaturated ketones. The optimal conditions have been found to include alcoholic sodium hydroxide as reaction medium and room temperature, which provide higher regioselectivity, 65–75% yields of the target unsaturated ketones, and the absence of byproducts. The presence of a C=C double bond activated by the carbonyl group in the molecules of the synthesized unsaturated ketones makes them promising substrates for the preparation of various potentially biologically active compounds. In particular, they reacted with hydrazine hydrate, thiosemicarbazide, and secondary amines to give new furan derivatives. [ABSTRACT FROM AUTHOR]

In this project, we have investigated the Diels–Alder (DA) reaction between euparin (as a natural furan derivative) and dimethyl acetylenedicarboxylate (DMAD) as an electrophilic acetylene. The experimental observations during the reaction in different conditions showed that the yield and the rate of the process would increase with increasing the polarity of the solvent. Such observation suspected us that like several recent reports, the mechanism of this DA reaction takes place through a stepwise route containing a zwitterionic intermediate or at least through a relatively polar transition state (TS). Next, during the density functional theory (DFT) studies and the potential energy surface (PES) investigations, we have detected a stepwise reaction pathway in parallel with the one-step route. The results of this work are in agreement with the recent reports about the competition between the one-step and multisteps routes in the DA reactions. [ABSTRACT FROM AUTHOR]

Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was utilized to analyze the volatile compounds in cooked barley. A total of 56 compounds were identified, including 18 aldehydes, 13 ketones, 6 alcohols, 6 furans, 5 acids, 2 furfurals, and 6 others. The grains of waxy and nonwaxy barley were pearled and stored at either 5 °C or 40 °C for 5 months prior to cooking. The waxy genotypes exhibited higher levels of key odorants in cooked barley, such as hexanal, 2-octenal, 2,4-nonadienal (E, E), and 2,4-decadienal (E, E), compared to the nonwaxy genotypes. Elevated storage temperatures (40 °C) led to an increase in 42 volatile compounds, particularly 2-butyl-2-octenal in cooked barley. Principal component analysis revealed distinguishable profiles of volatile compounds among the nonwaxy 40 °C storage group, the waxy hull-less 40 °C storage group, the waxy hulled 40 °C storage group, and the 5 °C storage group. [ABSTRACT FROM AUTHOR]

This document discusses the synthesis and utilization of furans and their derivatives as platform chemicals in the chemical industry. Furans, such as furfural and 5-hydroxymethylfurfural (HMF), can be derived from hemicellulose and cellulose and used in various reactions to produce renewable biofuels and biochemicals. However, the reactivity of furans also leads to the formation of significant by-products, making the development of sustainable processes challenging. The document presents recent advances in furan synthesis and utilization, focusing on catalytic systems, process conditions, and kinetic and mechanistic aspects. The papers highlight the importance of furanic compounds for the development of biorefineries and a sustainable energy transition. [Extracted from the article]

The present work models the fermentation process parameters of the newly isolated, Meyerozyma caribbica CP02 for enhanced xylitol production and its fermentability study on rice straw hydrolysate. The study examined the impact of each of the process variables by one variable at a time optimization followed by statistical validation. Temperature of 32 °C, pH of 3.5, agitation of 200 rpm, 1.5% (v/v) inoculum, 80 gL−1 initial xylose was optimized. Subsequently, a sequential two-stage agitation approach was adopted for fermentation. At these optimized conditions, xylitol yield of 0.77 gg−1 and 0.64 gg−1 was achieved using media containing commercial and rice straw derived xylose, respectively. For scale up, in 3L batch bioreactor, the highest xylitol yield (0.63 gg−1) was attained at 72 h with rice straw hydrolysate media containing initial xylose (59.48 ± 0.82 gL−1) along with inhibitors (1.55 ± 0.10 gL−1 aliphatic acids, 0.0.048 ± 0.11 gL−1 furans, 0.64 ± 0.23 gL−1 total phenols). The results imply that even under circumstances characterized by an acidic pH and elevated initial xylose level, M. caribbica CP02, as an isolate, displays robustness and shows favorable fermentability of rice straw hydrolysate. Therefore, isolate CP02 has potential to be used in bio-refineries for high yield xylitol production with minimal hydrolysate processing requirements. [ABSTRACT FROM AUTHOR]

In the chemistry community, catalytic asymmetric synthesis of furan‐based compounds bearing both axial and central chirality has proven to be a significant but challenging issue owing to the importance and difficulty in constructing such frameworks. In this work, we have realized the first catalytic asymmetric synthesis of five‐five‐membered furan‐based compounds bearing both axial and central chirality via organocatalytic asymmetric (2+4) annulation of achiral furan‐indoles with 2,3‐indolyldimethanols with uncommon regioselectivity. By this strategy, furan‐indole compounds bearing both axial and central chirality were synthesized in high yields with excellent regio‐, diastereo‐, and enantioselectivities. Moreover, theoretical calculations were conducted to provide an in‐depth understanding of the reaction pathway, activation mode, and the origin of the selectivity. [ABSTRACT FROM AUTHOR]

A previously undescribed aryne derived from a π‐extended biphenylene, 2,3‐didehydrobenzo[b]biphenylene, has been developed. The participation of this new aryne building block in [4+2] and palladium‐catalyzed [2+2+2] cycloaddition reactions has been applied to the synthesis of a variety of polycyclic conjugated hydrocarbons (PCHs) with appealing structures which combine (aromatic) benzene and (antiaromatic) cyclobutadiene (CBD) rings. Among them, a family of unsubstituted (or barely substituted) CBD‐oligoacenes has been accessed by iterative Diels‐Alder reactions of the new aryne with furans and/or isobenzofurans, followed by deoxygenative aromatization of the resulting epoxy‐derivatives. The experimental and computational studies of the newly synthesized PCHs suggest an important degree of electron delocalization along the polycyclic skeleton, more pronounced in the linearly fused derivatives. The computed ACID plots reveal clockwise current density vectors at the peripheral bonds, originating from the σ contributions of the antiaromatic cyclobutadiene rings. [ABSTRACT FROM AUTHOR]

The mechanism of the enantioselective (4+3) cycloaddition between furan derivatives and oxyallylcations, which are generated from the corresponding oxiranes through in situ oxidation of allenamides, has been studied using DFT methods. The research has revealed that, under acid‐catalysis by a chiral non‐racemic phosphoramide, the epoxide ring‐opening proceeds without any energy barrier, while the rate‐limiting step is the electrophilic attack of the intermediate enaminium ion on the furan ring. The reaction exhibits low energy barriers when dealing with furan derivatives unsubstituted at C2 and C5. Calculations predict the formation of an achiral regioisomer for 2‐substituted furans, a prediction that has been experimentally confirmed. Additionally, the calculations accurately predict the reaction with substituted allenamides. [ABSTRACT FROM AUTHOR]

Sustainability in chemical processes is a crucial aspect in contemporary chemistry with sustainable catalysis as a vital parameter of the same. There has been a renewed focus on utilizing earth‐abundant metal catalysts to expand the repertoire of organic reactions. Furan is a versatile heterocycle of natural origin used for multiple applications. However, it has scarcely been used in cross‐dehydrogenative coupling. In this work, we have explored the cross‐dehydrogentive coupling of furans with indoles using commonly available, inexpensive FeCl3 ⋅ 6H2O (<0.25 $/g) as catalyst in the presence of so called 'ultimate oxidant' – oxygen, without the need for any external ligand or additive. The reactions were found to be scalable and to work even under partially aqueous conditions. This makes the reaction highly economical, practical, operationally simple and sustainable. The methodology provides direct access to π‐conjugated short oligomers consisting of furan, thiophene and indole. These compounds were found to show interesting fluorescence properties with remarkably large Stokes shift (up to 205 nm). Mechanistic investigations reveal that the reaction proceeds through chemoselective oxidation of indole by the metal catalyst followed by nucleophilic trapping by furan. [ABSTRACT FROM AUTHOR]

In this work, the synthesis and characterization of highly aromatic bisoxazoline (BOX) monomers containing diphenyl ether, furan, and thiophene backbones are presented. Preliminary investigations of the cure and reaction kinetics are performed to understand the impact of these moieties on polymerization and their glass transition temperatures. To do this, two catalysts are used, methyl triflate (MT) and dodecyl benzene sulfonic acid (DBS) to explore their role in controlling the cationic ring‐opening polymerization (CROP) mechanism. Polymerization was monitored using non‐isothermal differential scanning calorimetry and characterized according to the Kissinger and Ozawa models. Kinetic modeling using the Malek and Sestak‐Berggren methods showed excellent agreement with experimental values and was used to determine reaction rate constants. The polymerization of BOX monomers in the presence of both MT and DBS is shown to be highly latent, being stable until the melting point is reached, after which reaction occurs rapidly. [ABSTRACT FROM AUTHOR]

The combination of electronic nose and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was used to analyse the differences in volatiles in soybean oil from three processing methods, which was extracted oil, hot pressed oil and cold pressed oil, respectively. The results showed that 86 volatile com¬pounds were detected in the three soybean oil samples, 53 of them in the extracted oil, 54 of them in the hot pressed oil and 45 in the cold pressed oil. The main volatile components included aldehydes, alcohols, ketones, acids, esters, terpenes, heterocycles (furans and pyrazines) and hydrocarbons and so on. 24 volatile components were identical in the three types of soybean oil. The principal component analysis and hierarchical cluster analysis indicated that the processing method had a big impact on the flavour of soybean oil. By odour activity value (OAV) technique, there were 15 key flavour compounds detected in the extracted oil, dominated by substances such as 3-nonen-2-one, resulting in a berry flavour in the extracted oil. Moreover, 16 key flavour compounds detected in hot pressed oil, which reflected distinctive baking flavour due to heterocyclic compounds such as 2, 5 -dimethylpyrazine. However, 12 key flavour compounds were detected in the cold pressed oil, dominated by aldehydes such as (A,A)-2,4-heptadienal, which gave natural oil flavour of the cold pressed oil. The results of the partial least squares regression analysis showed a good correlation between the electronic nose and the GC-MS results. [ABSTRACT FROM AUTHOR]

Wittig olefination at hetero-benzylic positions for electron-deficient and electron-rich heterocycles has been studied. The electronic effects of some commonly used protective groups associated with the N-heterocycles were also investigated for alkenes obtained in the context of the widely employed Wittig olefination reaction. It was observed that hetero-benzylic positions of the pyridine, thiophene and furan derivatives were stable after Wittig olefination. Similarly, electron-withdrawing groups (EWGs) attached to N-heterocycles (indole and pyrrole derivatives) directly enhanced the stability of the benzylic position during and after Wittig olefination, resulting in the formation of stable alkenes. Conversely, electron-donating group (EDG)-associated N-heterocycles boosted the reactivity of benzylic alkene, leading to lower yields or decomposition of the olefination products. [ABSTRACT FROM AUTHOR]

The treatment of N-tosylpropargyl amines 1 with 1,3-dicarbonyl compounds 2 in the presence of AuBr3 (5 mol%) and AgOTf (15 mol%) afforded poly-substituted furans 3 in good-to-high yields via the gold-catalyzed cleavage of the sp3 carbon–nitrogen bond. [ABSTRACT FROM AUTHOR]

The rapid emergence of drug resistant pathogens is a major threat which has warranted the development of alternative strategies to combat infectious diseases. In this work, we have tested the anti-virulent activity of Meldrum's acid activated furan (MAF) and 1,3-dimethyl barbituric acid activated furan (BAF) against Chromobacterium violaceum and Pseudomonas aeruginosa. It was found that MAF significantly reduced the violacein production and biofilm formation of C. violaceum at sub-inhibitory concentrations. The quorum sensing (QS) regulated virulence factors of P. aeruginosa including biofilm formation, motility, pigment production, and elastase activity were also found to be reduced considerably at sub-inhibitory concentrations of MAF. Additionally, MAF downregulated the expression of genes in the QS circuitry of P. aeruginosa, demonstrating the potential of MAF in lowering the pathogenicity of P. aeruginosa. In silico studies demonstrated the potential of MAF to compete with the signaling molecules of C. violaceum and P. aeruginosa for the QS receptor interaction. In vivo studies using Caenorhabditis elegans demonstrated the anti-pathogenicity of MAF by enhancing the survival of P. aeruginosa-infected C. elegans. These results suggest that activated furan compounds could be potential inhibitors of QS-mediated virulence factors in C. violaceum and P. aeruginosa, encouraging their use in combating multidrug-resistant pathogens. [ABSTRACT FROM AUTHOR]

A SeO2‐mediated regioselective synthesis of multi‐substituted furans has been achieved through intermolecular cyclization of terminal alkynes with aldehydes. The developed methodology used commercially available starting materials and afforded various 2,3,5‐triarylfurans. [ABSTRACT FROM AUTHOR]