A protocol of C-C direct coupling of the C-2 position of 3-acetylaminofuran, derived from biomass, with quinoxalinone was reported for the first time. This study confirmed that the quinoxalinone free radical, generated by acid protonation and illumination, is used to perform C-C dehydrogenation coupling with 3-acetylaminofuran (3AF), in which oxygen participates in the reaction process. On this basis, acid-catalyzed deacetylation was used to obtain the corresponding aminofuran derivatives. Intramolecular dehydration can be realized to form an imine tetracyclic compound.

Herbal residues (HRs) are emerging as an important and sustainable biomass resource, driven by the diversification of global health concepts and the rapid growth in related consumption. Herein, we established a valorization route from starch-rich traditional Chinese herb residues (TCHRs) to high-value 5‑keto‑D‑gluconic acid (5KGA) via a multi-enzymatic cascade. Starch-rich TCHRs were first converted to gluconic acid (GA) through enzymatic hydrolysis and oxidation (>80% conversion). Subsequently, an oxidized cofactor regeneration system was established to efficiently convert GA into 5KGA by coupling gluconate-5-dehydrogenase (Ga5DH) with a synthetic bridged-flavin analogue (SBFA), thereby mitigating constraints arising from Ga5DH's high reductive activity. This system catalyzed the irreversible dehydrogenation of GA to 5KGA, achieving complete conversion of 100 mM GA within 4 h (total turnover number, TTN = 1.0 × 104). Furthermore, upon scaling up in a 1-L bioreactor with continuous operation for 48 h, 203.3 g/L (950 mM) of 5KGA was produced with a TTN of 9.5 × 104. This value-upgrading strategy provides an efficient and economically viable biotransformation pathway for starch-based non-edible biomass feedstocks.

A novel protocol of photodriven, TFA-mediated oxidative coupling of quinoxalin-2(1H)-ones with 5-pyrazolones to prepare 4-quinoxalinone-pyrazolones has been realized under air. A visible-light-catalyzed method was first employed to synthesize these derivatives and the reactions afforded the desired products moderate to excellent yields. This protocol can be applied to the efficient synthesis of quinoxalinone drug analogs. Mechanistic investigation suggested that a radical pathway exists and TFA plays an important role in the formation of the products.

A protocol of photoinduced, 4CzIPN-catalyzed oxidative dehydrogenative coupling of quinoxalin-2(1H)-ones with aromatic amines to prepare 3-aryl-aminoquinoxalin-2(1H)-ones has been realized open to air. 3-Aryl-aminoquinoxalin-2(1H)-one derivatives were comprehensively synthesized from aromatic amines using the photocatalytic method in this article, and the reactions proceeded in moderate-to-excellent yields. This protocol can be applied to the efficient synthesis of bioactive quinoxalinone derivatives in a single step. Mechanistic investigation indicated that a radical pathway existed in the formation of the products.

Photocatalytic reforming of polyols to formic acid in acetonitrile-free aqueous solutions suffers from low selectivity due to excessive hydroxyl radical (& sdot;OH) formation, while the formation mechanisms of & sdot;OH in aqueous solutions, their regulation strategies, and the mechanisms by which they influence the photoreforming of polyols remain unclear. This work investigates regulating reactive oxygen species (ROS) by varying TiO2 anatase/rutile ratios. EPR and DFT revealed a stepwise O2 reduction pathway (O2 -> & sdot;O2 -> & sdot;OH) in aqueous solution. Rutile TiO2, with higher oxygen vacancies and conduction band potential, promotes ROS generation. However, excess & sdot;OH leads to formic acid deep oxidation, reducing selectivity as rutile content increases. Anatase/rutile heterojunctions enhance charge separation and glycerol conversion. TiO2 with 74 % anatase achieved 66 % glycerol conversion and 42 % formic acid selectivity after 10 h of reaction, yielding the highest formic acid production of 28 %. Mechanistic studies indicated glycolaldehyde conversion, a key step, requires & sdot;OH (favored by rutile), while formic acid oxidation is driven by anatase holes. Crucially, increasing solution pH suppressed & sdot;OH formation, boosting formic acid selectivity. This work clarifies the TiO2 crystal phase-dependent ROS regulation mechanism, offering new theoretical guidance for the highly selective photoreforming of polyols to formic acid in aqueous solution.

The cleavage of C-C bonds to generate small molecules is a pivotal strategy for integrating shell bio-refinery products into the conventional chemical industry. Herein, we synthesized a novel bifunctional acetylacetone molybdenum-based catalyst with oxygen vacancies and acid sites (Ov-Mo-acac), which catalyze the retro-aldol reaction of N-acetylglucosamine (NAG), consequently the condensation with acetylacetone and dehydration to co-produce furan and pyrrole compounds. Reaction optimization resulted in a remarkable yield of 95 % for Nacetyl-3-acetyl-2-methyl pyrrole (AMAP) and 74 % for 5-(1,2-dihydroxyethyl)-2-methyl-3-acetylfuran (DMAF) from NAG at 90 degrees C for 3 h. XPS, EPR, and Raman confirmed the reduction of molybdenum from the Mo6+ to Mo5+ and Mo4+, and oxygen vacancies on the surface. Furthermore, the catalyst has Lewis and Br & Oslash;nsted acidic sites, as evidenced by py-FTIR and 1 H MAS NMR. The study offers a new approach to utilizing shellfishery waste and sheds the function of oxygen vacancies on Mo-based catalysts for the retro-aldol reaction of carbohydrates.

Polyether-modified polysiloxane is widely used in emulsion defoamer formulations. In this study, we introduced the fluoroalkyl group to prepare polyfluorosiloxane (FHPS) and polyether-modified polyfluorosiloxane (FEPS) via ring-opening polymerization and hydrosilylation. After optimization, the yield of FHPS can reach 78.57%, with a surface tension of 17.24 mNm(-1); the yield of FEPS is 93.16%, with a surface tension of 20.68 mNm(-1). The synthesized FEPS exhibits good thermal stability with a critical micelle concentration of 21.37 mgL-1. Then, emulsion defoamers were formulated using FEPS as de- and anti-foaming components. The best emulsion has an average particle size of 15.11 mu m, which was prepared by the phase inversion method. In the sodium dodecylbenzene sulfonate (SDBS) solution, the foam elimination time is 7.0 s, and the antifoam time is 45.2 min. In the rhamnolipid solution, the foam elimination time is 7.4 s, and the antifoam time is 40.8 min. The synthesized polyether-modified polyfluorosiloxane shows great potential for application in defoamers.

Difuropyridines have been prepared from aldehydes and chitin-derived 3-acetamidofuran (3AF) under acid-catalyzed conditions. Difuropyridines were comprehensively synthesized for the first time. The synthesized difuropyridines can be applied to prepare fluorescent probe analogs or catalyze decarboxylative reactions as photocatalysts.

An approach to improving the efficiency of alkali-catalyzed glucose isomerization into fructose by adding alkaline earth metal salts was explored. 70.3% fructose yield with 99% fructose selectivity can be achieved in Ca(OH) 2 –CaCl 2 solution at 50 °C for 25 min.

Chitin, as the second most abundant biomass in nature, possesses 7 wt % biologically fixed nitrogen, and its direct valorization into valuable nitrogen (N)-containing chemicals is optimal. Herein, we report the biosynthesis of two specific furan-based amine compounds, 2-acetyl-4-aminofuran (2A4AF) and 3-acetylamino-5-(alpha-aminoethyl)-furan (3A5AEF), from chitin-derived 3-acetamido-5-acetylfuran (3A5AF) via biocatalytic deacetylation and reduction amination, respectively. An amidase (MmH) from Starkeya sp. and an R-selective aminotransferase (ATA117) from Arthrobacter sp. were obtained, which can, respectively, convert 3A5AF to 2A4AF with a yield of 79.3% (47.58 mM) and (R)-3A5AEF (enantiomeric excess (ee) value of >99%) with a yield of 84.0% (126 mM), respectively, under the optimal conditions. The biosynthesis efficiency of the two amines was high in comparison with chemical approaches. This work paves the way for green and efficient production of furan-based amino chemicals from inexpensive renewable chitin resources.

L-Proline cis-4-hydroxylase (cis-P4H), a non-heme Fe2+/alpha-ketoglutarate-dependent dioxygenase (KDD), finds application in proline C4 hydroxylation and selective L-pipecolic acid (L-PA) C5 hydroxylation. Nonetheless, its regioselectivity is often ambiguous, yielding nearly equal amounts of cis-5/cis-3 hydroxylated L-PA isomers, posing challenges in separation and purification. In this study, we selected Kordia jejudonensis proline hydrox-ylase (KjPH) for modification and investigated the electrostatic effect's molecular mechanism on its regiose-lectivity. Through sequence and catalytic domain alignment of KjPH (cis-5/cis-3 = 20:1), SmP4H (cis-5/cis-3 = 1:1, from Sinorhizobium meliloti), and MlP4H (cis-5/cis-3 = 1:7, from Mesorhizobium loti), we identified four non-conserved key residues (Y35, S57, F95, and C97). We confirmed that F95 in KjPH plays a pivotal role in affecting regioselectivity. The single-site variant F95Y significantly enhanced regioselectivity, increasing the cis-5/cis-3 ratio from 20:1 to 55:1. Molecular dynamics simulations unveiled that the improved regioselectivity of the F95Y variant primarily resulted from the electrostatic repulsive interaction, which increased the distance between the substrate's C3 site and the Fe2+ catalytic core.

A chemo-enzymatic strategy for achieving furan-2,5-dicarboxylic acid precursors via 5-keto-d-gluconic acid as a stable intermediate.

Roots and stems comprise a large proportion of traditional Chinese medicines and often serve as the energy storage units of plants. However, their decoction residues still contain a significant amount of starch, and direct landfilling, incineration, or carbon disposal results in a wastage of resources. In this study, five types of starch-rich traditional Chinese medicine decoction residues (TCMDRs)c, namely, Radix Isatidis Rhizoma Dioscoreae, Rhizoma Corydalis and Fritillaria Thunbergii. Radix Paeoniae Alba were screened and hydrolyzed using amylase-glucoamylase to produce fermentable sugar. The resulting glucose yields were 87.54

Based on the demand of enterprise talents and the characteristics of manufacturing process management in biotechnology, in order to make the students acquire the ability to solve complex engineering problems in the production process, we developed a "Comprehensive Biotechnology Experiment" course, where two-step enzymatic production of l-aspartate and l-alanine were the key processes. In this course, we drew lessons from the site management of the production enterprise, performed the experimental operation mode of four shifts and three operations. The content of this course includes principles, methods and experimental techniques of several core curricula and the site management mode of enterprises. As to the evaluation, the summary of the experimental staff's handover records and the content of teamwork were examined and scored. Through teaching practice and continuous improvement, we developed a complete experimental teaching process and assessment mechanism. Overall, the Comprehensive Biotechnology Experiment course achieved good teaching effect, which may serve as a reference to promote the development of experimental teaching of biotechnology.

Aminofurans are widely used in drug synthesis as aromatic modules analogous to aniline. However, unsubstituted amino-furan compounds are difficult to prepare. In this study, a process for the selective conversion of N-acetyl-D-glucosamine (NAG) into unsubstituted 3-acetamidofuran (3AF) is developed. The yield of 3AF from NAG catalyzed by a ternary Ba-(OH)(2)-H3BO3-NaCl catalytic system in N-methylpyrrolidone at 180 degrees C for 20 min can reach 73.9 %. Mechanistic studies reveal that the pathway to 3AF starts with a base-promoted retro-aldol condensation of the ring-opened NAG, affording the key intermediate N-acetylerythrosamine. Judicious selection of the catalyst system and conditions enables the selective conversion of biomass-derived NAG into 3AF or 3-acetamido-5-acetylfuran.

Isatis indigotica Fort. root (Ban-lan-gen, IIR), a traditional Chinese medicine (TCM), has an ancient and well-documented history for its medicinal properties. Aside from epigoitrin, indole alkaloids, and their corresponding derivatives as medicinal ingredients, it also contains lots of biomass such as starch. Herein, a new starch was isolated from IIR and the physicochemical properties such as amylose content, moisture content, ash content, morphology, thermal properties, and crystallography were characterized systematically. The amylose content of IIR starch was 19.84 ± 0.85%, and the size and shape of starch granules is ellipsoidal shape with sizes from 2 to 10 μm. IIR starch exhibited a C-type pattern and had 25.92% crystallinity (higher than that of corn starch). The gelatinization temperature of IIR starch was 58.68–75.41 °C, and its gelatinization enthalpy was Δ H gel = 4.33 J/g. After decocting, the IIR’s residues can be used to prepare anhydro-sugars in a polar aprotic solvent. The total carbon yield of levoglucosan (LG), levoglucosenone (LGO), 5-hydroxymethylfurfural (HMF), and furfural (FF) could reach 69.81% from IIR’s decoction residues in 1,4-dioxane with 15 mM H 2 SO 4 as the catalyst. Further, the residues after dehydration were prepared into biochar by thermochemical conversion and the BET surface area of biochar was 1749.46 m 2 /g which has good application prospect in soil improvement and alleviates obstacles of IIR continuous cropping.

FDCA (2,5-furandicarboxylic acid), produced by oxidizing carbohydrate-derived HMF (5-hydroxymethylfurfural), is a valuable monomer for biopolymers. The difference in the solvent system between the dehydration reaction and oxidation reactions seriously affects the process continuity and production efficiency. Herein, we reported a cascade process for FDCA production from carbohydrates in a single acetic acid system. The fructose conversion was complete and total furan compounds yield reached nearly 90

Herein, we propose a facile method for converting N-acetyl-D-glucosamine (NAG) into the N-containing chemical 3-acetamido-5-acetylfuran (3A5AF) using chloride salt as a catalyst. Screening of various chloride salts showed that NH4Cl possessed the optimal catalytic performance. The catalyst NH4Cl led to a 3A5AF yield of 43 mol % with LiCl as an additive in N,N-dimethylformamide (DMF) solvent at 160 degrees C for 5 min. Moreover, the solvent, catalyst and additive could be reused at least five times with residual catalytic activity of 94.42 %. Additionally, scaling up of the 3A5AF preparation could be easily realized and the purity of the product 3A5AF reached >99 % purity with 45 mol % isolated yield after a simple isolation procedure. This work provides an environmentally friendly and mild method for converting NAG into 3A5AF.

Oily sludge (OS) from steel mills contains a large number of heavy components and has high viscosity. In this paper, the preparation of high value-added gas from the pyrolysis of OS catalyzed by calcined olivine (C-OL), xiuyan jade (C-XY), iddingsite (C-ID) and their nickel carrier was investigated. ICP, SEM, EDX, XRF, and XRD were applied to characterize the catalysts. The effect of the catalyst on the pyrolysis of OS and the regulation mechanism of gas product quality were investigated. Thermogravimetric results showed that all the six catalysts could improve the total weight loss rate of OS, among which the addition of C-OL(Ni) increased by 11.58%. Compared with the pyrolysis of OS, the production of H2 increased by 23.64% and 6.72% after C-OL and C-XY were added at 900°C, respectively. Ni ore-based catalysts can promote tar cracking, thereby producing more pyrolysis gas, in which the yield of H2 is significantly increased. The addition of C-XY(Ni) increased the production of H2 by 68.44%. After nickel was loaded, the catalysts showed better catalytic activity at a high temperature. Results show that the nickel-loaded natural ore as catalyst can promote the pyrolysis of OS and can obtain pyrolysis gas with high added value.