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Conical intersections (CIs) play a crucial role in photochemical reactions, offering an efficient channel for ultrafast non-adiabatic relaxation of excited states. This significantly influences the reaction pathways and the resulting products. In this work, we utilize the non-Markovian stochastic Schrödinger equation with complex modes method to explore the dynamics of electronic transitions through conical intersections (CIs) in pyrazine. The linear vibronic coupling model serves as the foundational framework, incorporating both intra-state and inter-state electron–vibrational interactions. The dynamics of the excited electronic transitions are analyzed across varying strengths of system–bath coupling and different bath relaxation times. The accuracy of this method is demonstrated by comparing its predictions with those from the hierarchical equations of motion method. [ABSTRACT FROM AUTHOR]

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Mesenchymal-epithelial transition (MET) signaling pathway plays a role in the pathogenesis of selected patients with papillary renal cell carcinoma (PRCC). In the phase II PAPMET trial (ClinicalTrials.gov identifier: NCT02761057), cabozantinib significantly prolonged progression-free survival and improved objective response rate compared with sunitinib in patients with advanced PRCC. Here, we present the final overall survival (OS) analysis. In this multicenter, randomized phase II, open-label trial, 147 patients with advanced PRCC who have received up to one previous therapy (excluding vascular endothelial growth factor-directed agents) were assigned to sunitinib, cabozantinib, crizotinib, or savolitinib. Ultimately, savolitinib and crizotinib arms were closed because of futility. With a median follow-up of 17.5 months, the median OS was 21.5 months (95% CI, 12.0 to 28.1) with cabozantinib and 17.3 months (95% CI, 12.8 to 21.8) with sunitinib (hazard ratio, 0.83; 95% CI, 0.51 to 1.36; P = .46). The OS landmark estimates for cabozantinib and sunitinib were 50% versus 39% at 24 months and 32% versus 28% at 36 months. In conclusion, we observed no significant difference in OS across treatment arms. Although cabozantinib represents a well-supported option for advanced PRCC, the lack of survival benefit underscores the need to develop novel therapies for this disease.

BACKGROUND: High-grade endometrial cancers (EAC) are aggressive tumors with a high risk of progression after treatment. As EAC may harbor mutations in the RAS/MAPK pathways, we evaluated the preclinical in vitro and in vivo efficacy of avutometinib, a RAF/MEK clamp, in combination with the focal adhesion kinase (FAK) inhibitors defactinib or VS-4718, against multiple primary EAC cell lines and xenografts. METHODS: Whole-exome sequencing (WES) was used to evaluate the genetic landscape of five primary EAC cell lines. The in vitro activity of avutometinib and defactinib as single agents and in combination was evaluated using cell viability, cell cycle, and cytotoxicity assays. Mechanistic studies were performed using Western blot assays while in vivo experiments were completed in UTE10 engrafted mice treated with either vehicle, avutometinib, VS-4718, or their combination through oral gavage. RESULTS: WES results demonstrated multiple EAC cell lines to harbor genetic derangements in the RAS/MAPK pathway including KRAS/PTEN/PIK3CA/BRAF/ARID1A, potentially sensitizing to FAK and RAF/MEK inhibition. Five out of five of the EAC cell lines demonstrated in vitro sensitivity to FAK and/or RAF/MEK inhibition. By Western blot assays, exposure of EAC cell lines to defactinib, avutometinib, and their combination demonstrated decreased phosphorylated FAK (p-FAK) as well as decreased p-MEK and p-ERK. In vivo the combination of avutometinib/VS-4718 demonstrated superior tumor growth inhibition compared to single-agent treatment and controls starting at Day 9 (p

We tested five chemically and metabolically stable prostaglandin (PG) receptor agonists in a mouse model of dexamethasone-induced ocular hypertension (OHT). Whilst all compounds significantly (p < 0.05, ANOVA) lowered intraocular pressure (IOP) after twice-daily bilateral topical ocular dosing (5 µg/dose) over three weeks, the time course and magnitude of the responses varied. The onset of action of NS-304 (IP-PG receptor agonist) and rivenprost (EP4-PG receptor agonist) was slower than that of misoprostol (mixed EP2/EP3/EP4-PG receptor agonist), PF-04217329 (EP2-PG receptor agonist), and butaprost (EP2-PG receptor agonist). The rank order of IOP-lowering efficacies aligned with the onset of actions of these compounds. Peak IOP reductions relative to vehicle controls were as follows: misoprostol (74.52%) = PF-04217329 (74.32%) > butaprost (65.2%) > rivenprost (58.4%) > NS-304 (55.3%). A literature survey indicated that few previously evaluated compounds (e.g., latanoprost, timolol, pilocarpine, brimonidine, dorzolamide, cromakalim analog (CKLP1), losartan, tissue plasminogen activator, trans-resveratrol, sodium 4-phenyl acetic acid, etc.) in various animal models of steroid-induced OHT were able to match the effectiveness of misoprostol, PF-04217329 or butaprost. Since a common feature of the latter compounds is their relatively high affinity and potency at the EP2-PG receptor sub-type, which activates the production of intracellular cAMP in target cells, our studies suggest that drugs selective for the EP2-PG receptor may be suited to treat corticosteroid-induced OHT.

A Cu-promoted highly chemoselective dimerization of 5-aminopyrazoles to produce pyrazole-fused pyridazines and pyrazines is reported. The protocol generates switchable products via the direct coupling of C-H/N-H, C-H/C-H and N-H/N-H bonds, with the merits of broad substrate scope and high functional group compatibility. Gram-scale experiments demonstrated the potential applications of this reaction. Moreover, the preliminary fluorescence results uncovered that dipyrazole-fused pyridazines and pyrazines may have some potential applications in materials chemistry. [ABSTRACT FROM AUTHOR]

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BACKGROUND RESULTS CONCLUSION The typical aroma compounds in methionine‐glucose Maillard products often undergo further degradation and polymerization during storage and thermal processing, leading to flavor dispersion and aroma distortion. It is crucial to identify measures that enhance typical aroma substances in such flavor matrices.The effect of oxygen on the flavor formation of methionine‐glucose thermal reaction system was explored by determining typical flavor substance contents and flavor differences. Compared with the oxygen concentration in the air (21%), a high oxygen concentration (30% and 40%) effectively promoted the formation of typical flavor substances. Pyrazines increased by 44% and thioethers increased by 13%. The reaction process and the content of key substances were both measured to explain the involvement of oxygen. It was found that high oxygen concentration increased the reaction efficiency of glucose and methionine and promoted the formation of α‐dicarbonyl compounds, including glyoxal, methylglyoxal and 3‐deoxyglucosinone. Moreover, a glyoxal‐methylglyoxal‐methionine model system was established to verify the effect of oxygen intervention on the formation of pyrazines and thioethers generating from α‐dicarbonyl compounds. It was confirmed that a high oxygen concentration promoted the consumption of glyoxal and methylglyoxal, which were more readily converted into pyrazines and thioethers without forming melanoidins.A high concentration of oxygen promoted the formation of pyrazines and thioethers during the Maillard reaction of methionine and glucose, and effectively inhibited the occurrence of browning. The present study provides a new concept for the typical flavor enhancement of methionine‐glucose Maillard reaction products. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The study investigated the effects of storage temperature, type of coffee, and brewing method on coffee's volatile compound profile and sensory quality. Three types of coffee were included in the study: Arabica, Robusta, and their 80/20 blend. Samples were stored at 5 °C and 20 °C for one month, after which the changes in the composition of volatile compounds were analysed and the sensory quality of espresso and cold brew coffee was assessed. The results showed that storing coffee at a lower temperature slows the changes in the profile of volatile compounds such as aldehydes, alcohols, pyrazines, and furans, helping preserve the desired aroma and flavour characteristics. Storage at higher temperatures resulted in greater changes in the volatile profile and sensory quality, with higher perceptions of earthy, sharp, and smoky notes and lower chocolatey and sweet notes. The brewing method also had a significant effect on the sensory quality. The espresso coffee had a higher intensity of coffee aroma, chocolate flavour, smoky aroma, and roasted notes. In contrast, cold brew coffee was perceived as sweeter, fruitier, and had more pronounced rum notes. The coffee type also significantly influenced the aroma and flavour profile. Arabica had a more harmonious and mild aromatic profile, while Robusta had a sharper aroma. The blend of Arabica and Robusta combined the characteristics of both coffees and offered a balanced aromatic profile. [ABSTRACT FROM AUTHOR]

2,3-Diamino-5,6-dichloropyrazine represents a valuable but underexplored heterocyclic building block. Due to the use of harsh conditions and lack of selectivity surrounding the known literature synthesis, we developed a more accessible and selective three-step route from 2-aminopyrazine. Challenging conditions are avoided by using a high-yielding dichlorination with N -chlorosuccinimide (NCS), which is followed by a regioselective amination. The installation of the last chlorine atom using 1-chloro-1,2-benziodoxol-3(1 H)-one is rapid, enabling access to 2,3-diamino-5,6-dichloropyrazine in an improved overall yield (41%). [ABSTRACT FROM AUTHOR]

The optimum processing conditions for green laver chips were determined using response surface methodology (RSM) to improve taste and reduce off-flavors by applying reaction flavor and air-frying techniques. The optimum composition (w/w) for the chips included 20% green laver, 20% hairtail surimi, and 60% flour. Additional ingredients included distilled water (90 mL) with GDL (3 g), NaHCO₃ (2 g), salt (1 g), sugar (12 g), roasted soybean powder (1.5 g), and reaction flavor solution (RFS, 10 mL). The mixture was kneaded, shaped, dried at 50 °C for 2 h, and air-fried at 195 °C for 80 sec. The resulting green laver chips showed overall acceptance and brittleness values of 7.00 ± 0.74 and 5.89 ± 0.59 N, respectively, with absolute residual errors of 8.43% and 7.07%. The optimum reaction flavor precursors for green laver chips were determined to be threonine (1.0 g%), proline (1.0 g%), glycine (1.4 g%), methionine (0.05 g%), and glucose (2 g%). Flavor analysis revealed that green laver chips with reaction flavor (GLCR) contained 13 alkylpyrazines with corn-like and nutty odors, and 2-acetylpyrrole, which contributed a popcorn-like odor. In contrast, green laver chips without reaction flavor (GLC) predominantly contained straight-chain aldehydes with undesirable odors. The heating process in the air fryer appeared to reduce the aldehyde content and promote pyrazine formation, significantly enhancing GLCR's flavor. [ABSTRACT FROM AUTHOR]

The industrial amino acid production workhorse, Corynebacterium glutamicum naturally produces low levels of 2,3,5,6-tetramethylpyrazine (TMP), a valuable flavor, fragrance, and commodity chemical. Here, we demonstrate TMP production (∼0.8 g L-1) in C. glutamicum type strain ATCC13032 via overexpression of acetolactate synthase and/or α-acetolactate decarboxylase from Lactococcus lactis in CGXII minimal medium supplemented with 40 g L-1 glucose. This engineered strain also demonstrated growth and TMP production when the minimal medium was supplemented with up to 40% (v v-1) hydrolysates derived from ionic liquid-pretreated sorghum biomass. A key objective was to take the fully engineered strain developed in this study and interrogate medium parameters that influence the production of TMP, a critical post-strain engineering optimization. Design of experiments in a high-throughput plate format identified glucose, urea, and their ratio as significant components affecting TMP production. These two components were further optimized using response surface methodology. In the optimized CGXII medium, the engineered strain could produce up to 3.56 g L-1 TMP (4-fold enhancement in titers and 2-fold enhancement in yield, mol mol-1) from 80 g L-1 glucose and 11.9 g L-1 urea in shake flask batch cultivation.One-sentence summaryCorynebacterium glutamicum was metabolically engineered to produce 2,3,5,6-tetramethylpyrazine followed by a design of experiments approach to optimize medium components for high-titer production.

Herein, we unveil a method for synthesizing substituted pyrrole and pyrazine compounds via a double dehydrogenative coupling of amino alcohols with primary alcohols, facilitated by Mn(I)–PNP catalysis, which uniquely enables the simultaneous formation of C–C and C–N bonds. [ABSTRACT FROM AUTHOR]

In series‐connected tandem organic solar cells (TOSCs), various light‐harvesting molecules with complementary absorptions are explored with the aim of collaboratively utilizing solar light to the maximum extent. In sharp contrast to the small molecular acceptors that possessing almost the successively tunable bandgaps, high‐performance wide‐bandgap (WBG) polymer donors in TOSCs are quite scarce, with only PM6 (optical bandgaps, Egopt = 1.80 eV) and D18 (Egopt = 1.98 eV) being widely used. Herein, to develop WBG polymer donors with large open‐circuit voltages (VOC) and high‐energy photon absorption, two pyrazinyl polymer donors, PPy1 and PPy2, are synthesized with branched 2‐butyloctyl and n‐dodecyl chains on polymeric backbones, respectively, demonstrating the downshifted highest occupied molecular orbital energy levels of ≈−5.60 eV and thus afford Egopt over 2.0 eV. Consequently, when blending with a WBG acceptor F‐ThCl, PPy2:F‐ThCl‐based devices exhibit a higher power conversion efficiency (PCE) of 14.50% and fill factor of 77.66%. In light of its large VOC of 1.07 V, TOSCs based on PPy2 are further fabricated and exhibit an impressive PCE of 19.35% by using a narrow bandgap blend of PM6:CH1007:F‐2F as a rear cell. This work demonstrates the great potential of pyrazine units in constructing WBG polymer donors for achieving record‐breaking TOSCs. [ABSTRACT FROM AUTHOR]

The exploration of cyclo‐N5ˉ‐based energetic cocrystals represents a noteworthy avenue within pentazolate chemistry, focusing on leveraging cocrystallization to enhance stability. Recently, a novel cocrystal explosive, N2H5N5/PDO, was developed by combining N2H5N5 with pyrazine 1,4‐dioxide (PDO), exhibiting promising detonation characteristics and reduced sensitivity. This study endeavors to elucidate how the structure and noncovalent interactions impact the performance of N2H5N5/PDO through a first‐principles investigation. The results indicate that the enhanced hydrogen bonding and wave‐like crystal packing structure within the cocrystal effectively bolster its stability compared to N2H5N5. The N···H and O···H interactions, in conjunction with π–π interactions, emerge as critical elements driving cocrystal formation. Compared to the pure N2H5N5, the detonation performance of the cocrystal exhibits a slight decline, albeit with a noticeable reduction in sensitivity. [ABSTRACT FROM AUTHOR]

Herein, we have developed palladium‐trifluoroacetate‐catalyzed carbo‐palladation reaction of pyrrole‐2‐carbonitriles and aryl boronic acids leading to functionally diverse pyrrolo[1,2‐α]pyrazines under thoroughly optimized reaction conditions. The reaction proceeded smoothly and allowed the diversity‐oriented synthesis of pyrrolo[1,2‐α]pyrazines with broad substrate scope with respect to pyrrole‐2‐carbonitriles and aryl boronic acids. [ABSTRACT FROM AUTHOR]

Context: Based on the methods of quantum chemistry and atom–atom potentials, the molecular and crystal structure of a number of high-energy pyrazines was modeled: unsubstituted diazines, as well as fully nitrated 1,4-diazabenzenes, their oxides and polymorphs. The enthalpies of formation, densities of molecular crystals, and some performance characteristics of these compounds were determined. The parameters of decomposition of substances were estimated. It has been established that tetranitropyrazine-1,4-dioxide has maximum energy content and excellent performance characteristics, which determine the prospects for using this compound as a high-energy one in the considered series of compounds. Methods: In this work, DFT calculations were conducted through the software Gaussian 09 using B3LYP functional with basis set aug-cc-PVDZ and the Grimme dispersion correction D2. For crystal structure optimization, the atom–atom potential methods with PMC program (Packing of Molecules in Crystal) were used. Charges for molecular electrostatic potential were fitted by FitMEP and enthalpies of formation in gas phase were assessed by G3B3. [ABSTRACT FROM AUTHOR]

Colored complexes of bidentate Lewis acids R[OB(C6F5)2]2 (R = p-C6H4, p-C6F4) with pyrazine have been synthesized. A mass spectrometric study of the obtained complexes was carried out, as a result of which it was established that upon heating, dissociation processes occur with a sequential transition into pyrazine and Lewis acid vapor. Using the method of diffuse reflectance spectroscopy in the visible and ultraviolet regions, the color of the compounds was characterized and a mechanism for its appearance was proposed, which consists in the presence of π–π interactions in the solid phase. [ABSTRACT FROM AUTHOR]

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Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recently, tumor-targeted radionuclide therapy has gained much recognition for the treatment of metastasized cancer. There is a growing interest in using the theranostic radionuclide 47Sc, owing to its excellent chemical and nuclear properties. However, the available chelating agents require a relatively high temperature for their radiolabeling, which could denature biomolecules. The aim of the present study is to synthesize a dipeptide agent that forms a thermodynamically more stable complex with 47Sc at room temperature. A novel α-amino acid ester derivative attached to pyrazine and tetrazole heterocyclic rings has been prepared by the azide coupling method. Different spectroscopic methods (FT-IR, 1H NMR, and mass spectra) were used for characterization of the target compound. The newly synthesized dipeptide was radiolabeled with 47Sc, and a high radiochemical yield of 98.5 ± 1.5 % and in vitro serum stability up to 72 h were attained at room temperature within 20 min. The quantum chemical calculations at B3PW91/6-31G(d) level were employed to establish the molecular structure of the dipeptide and its complexation with 47Sc. The selectivity of 47Sc-dipeptide toward localization in tumor cells was performed by molecular docking on different receptors in addition to in vivo biodistribution on solid tumor-bearing mice. A high T/NT ratio of 8.16 was obtained after 4 h p.i, suggesting that this complex could be used as a potential cancer theranostic agent. [ABSTRACT FROM AUTHOR]

In this study, the effect of protease hydrolysis on the stability and flavor of a sesame oil–paste system was investigated. The optimum amount of protease addition, determined by testing the effects of protease addition on the improvement in the oil–paste separation of sesame paste (SP), was investigated using 7% neutral protease (NP), 5% papain (PP), 7% trypsin (TP), and 5% flavourzyme (FZ). The flavor differences among these four groups of samples were investigated, and storage experiments were conducted for 28 days to observe the changes in quality. Finally, the principal component analysis (PCA) calculations showed that the samples in the 5% FP group performed the best, with a considerable improvement in the stability of the sesame paste–oil system during storage. The oil separation capacity (OSC) decreased by 9.1% during storage, the acid value (AV) increased by 1.00 mg/g and the peroxide value (POV) increased by 0.3 mmol/kg compared with those of the control group. This group also had the highest total sensory (4.25 score) and nutty (5.83 score) scores based on the total pyrazine content. Therefore, protease hydrolysis has promising application prospects for increasing the stability of sesame paste. [ABSTRACT FROM AUTHOR]

In this paper, a series of Zr metal‐organic frameworks, whose hexanuclear clusters of Zr are connected with luminescent rodlike dicarboxylic acids, are used for the construction of a sensor array to selectively detect various analyte vapors. The chemical functionalization of the ligand (HOOC[PE‐aryl‐EP]COOH) (which alternates phenylene(P) and ethynylene(E) units) through the aryl core, is focused on obtaining six Porous Interpenetrated Zirconium‐Organic Frameworks (PIZOFs) with distinctive luminescent properties. Particularly, the synthesis of two new ligands (aryl = nitrobenzene;metal‐organic frameworks aryl = pyrazine) enabled the preparation of new PIZOFs (UPO‐1 and UPO‐2) with submicron sizes, thanks to the use of a microwave‐assisted synthetic method. The fluorescence properties of these two new PIZOFs, along with four others already reported, are thoroughly evaluated and noticeable changes are observed in their optical properties based on variations in the aryl core of the ligands. Furthermore, the presence of various volatile analyte vapors particularly modified their characteristic emission, resulting in multiple optical responses that are combined to achieve selectivity in detecting these analytes. Specifically, the construction of a fluorescent sensor array is proposed, incorporating the six PIZOFs into polyvinylidene‐fluoride (PVDF) films, capable of producing unique identification patterns for each analyte by leveraging the cross‐responsiveness of these sensing materials. [ABSTRACT FROM AUTHOR]

Virulent Klebsiella oxytoca strains are associated with gut and lung pathologies, yet our understanding of the molecular signals governing pathogenesis remains limited. Here, we characterized a family of K. oxytoca pyrazine and pyrazinone autoinducers and explored their roles in microbial and host signaling. We identified the human mucin capping sugar Neu5Ac as a selective elicitor of leupeptin, a protease inhibitor prevalent in clinical lung isolates of K. oxytoca, and leupeptin-derived pyrazinone biosynthesis. Additionally, we uncovered a separate pyrazine pathway, regulated by general carbohydrate metabolism, derived from a broadly conserved PLP-dependent enzyme. While both pyrazine and pyrazinone signaling induce iron acquisition responses, including enterobactin biosynthesis, pyrazinone signaling enhances yersiniabactin virulence factor production and selectively activates the proinflammatory human histamine receptor H4 (HRH4). Our findings suggest that the availability of specific carbohydrates delineates distinct autoinducer pathways in K. oxytoca that may have differential effects on bacterial virulence and host immune responses. Differential carbohydrate metabolism elicits distinct pyrazine and pyrazinone autoinducer signalling pathways in Klebsiella oxytoca, which impact bacterial virulence programs. [ABSTRACT FROM AUTHOR]

Flat black tea (FBT) has been innovatively developed to alleviate homogenisation competition, but the dynamic changes in aroma components during the process remain unclear. This study employed HS-SPME-GC-MS to analyse the aroma components of tea samples from various processing stages of FBT, and to make a comparative assessment with conventional strip-like Congou black tea (SBT). Additionally, a proteomic analysis was conducted on fresh leaves, withered leaves, and frozen–thawed leaves. Significant changes were observed in the aroma components and proteins during the processing. The results of the multivariate and odour activity value analysis demonstrated that the principal aroma components present during the processing of FBT were linalool, (E)-2-hexen-1-al, methyl salicylate, geraniol, hexanal, benzeneacetaldehyde, (Z)-3-hexenyl butyrate, dimethyl sulphide, 2-methylbutanal, 2-ethylfuran, nonanal, nonanol, 3-methylbutanal, (Z)-3-hexen-1-ol, 2-pentylfuran, linalool oxide I, and β-myrcene. Freezing–thawing and final roasting are the key processing steps for forming the aroma quality of FBT. The final roasting yielded a considerable quantity of pyrazines and pyrroles, resulting in a high-fried aroma, but caused a significant reduction in linalool, geraniol, β-myrcene, and esters, which led to a loss of floral and fruity aromas. The freezing–thawing treatment resulted in an accelerated loss of aroma substances, accompanied by a decrease in the expression level of lipoxygenase and 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase. The formation of aroma substances in the linoleic acid metabolic pathway and terpenoid metabolic process was hindered, which had a negative impact on tea aroma. This study elucidates the causes of unsatisfactory aroma quality in tea products made from frozen tea leaves, providing theoretical support for the utilisation of frostbitten tea leaves, and helps us to understand the mechanism of aroma formation in black tea. [ABSTRACT FROM AUTHOR]

The reduction of oximes was recently identified as a promiscuous activity of Old Yellow Enzymes (OYEs). This reaction involves a two‐step reduction of α‐oxime‐ß‐ketoesters to the corresponding amines, which spontaneously dimerise to yield pyrazine derivatives. This biotransformation is currently limited to substrates with small substituents like methyl/ethyl on the keto moiety. We used a structure‐based approach to engineer 12‐oxophytodienoate reductase 3 (OPR3) from Solanum lycopersicum as a prototypical OYE to accept oximes with bulkier substituents. To this end, three single and two double variants were prepared and tested on six oxime substrates. The engineered variants indeed showed activity on some of the bulkier substrates, which had not been converted at all by the wild‐type enzyme, including the diester compound diethyl‐2‐(hydroximino) malonate. While we were unable to identify variants capable of converting substrates with branched and aromatic substituents, the results demonstrate the validity of our engineering approach, suggesting potential pathways for expanding the substrate scope of OYEs. [ABSTRACT FROM AUTHOR]

d‐Allulose, a C‐3 epimer of d‐fructose, is a rare sugar with ∼70% of the sweetness of sucrose but a caloric content of only 0.4 kcal/g. Due to its low‐calorie nature, d‐allulose has garnered increasing interest in the food industry. This study was the first attempt to explore the effect of d‐allulose as a sucrose replacer on the properties of sponge cake, a widely consumed high‐sugar product. Substituting sucrose with d‐allulose generated negligible impact on the batter system, while pronounced differences in physicochemical properties of cakes were detected, including specific volume, texture, microstructure, color, and antioxidant activity. In addition, sponge cake containing d‐allulose displayed a distinctive aroma volatile profile, with more furans and pyrazines generation. Furthermore, correlations of physicochemical properties across all formulations were depicted, and the potential mechanism behind the property alterations modulated by d‐allulose was revealed from the perspectives of starch gelatinization and browning reactions. Overall, this study provides insights into the application potential of d‐allulose as a sucrose substitute in bakery product. Practical Application: This study elucidates the effect of d‐allulose as a low‐calorie sugar substitute on sponge cakes. This finding is valuable for the food industry, providing insights into a healthier alternative to traditional sugar in baked goods. [ABSTRACT FROM AUTHOR]

A simple and efficient method for concise synthesis of pyrido[3,2-e]pyrrolo[1,2-a]pyrazine deriva-tives based on Pictet–Spengler type cyclization reaction has been successfully developed. This procedure tolerates different types of aldehydes and ketones as starting materials in the presence of trifluoroacetic acid to provide the desired heterocyclic products with medium to excellent yields. The heterocycle containing bromine could be further used as a building block to synthesize more complex compounds. This strategy is characterized by simple operation and environmental friendliness and is a reliable tool for synthesizing bioactive substances. [ABSTRACT FROM AUTHOR]

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AbstractDye-sensitized solar cells (DSSCs) have garnered significant attention due to their exceptional ability to convert solar energy into electricity at a relatively low cost. Novel organic photosensitizers (FZB1-FZB9) from the pyrazine-based aromatic dye (E)-3-(5-(2,3-bis(40-(diphenylamino)-[1,10-biphenyl]-4-yl)-7 (trifluoromethyl)quinoxalin-5-yl)thiophen-2-yl)-2-cyanoacrylic acid (TPPF) have been quantum chemically modeled for their application in dye-sensitized nanocrystalline TiO2 solar cells (DSSCs). The electrochemical and photovoltaic features of modeled dyes are investigated by performing DFT insights, i.e. FMOs, absorption maxima, DOS, TDM, NBO, exciton and binding energy, radiative lifetime analysis (ꚍ), electron-injection (ΔGinject) and regeneration analysis (ΔGdyeregen)@TiO2. FMO analysis confirmed the better electron injection as HOMO of designed dyes was found to be more positive than redox potential I/I3 (-4.8 eV), and the LUMO appeared more negative than the conduction band of TiO2 (-4.0 eV). The modeled photosensitizers exhibited red shift λmax from 338-494 nm with a lower energy gap from 5.62 eV in FZB (R) to 5.17 eV in FZB9. Bridging modification reduces the exciton and binding energy for designed dye FZB9 and FZB7 compared to reference FZB. The designed dyes appeared with a lower radiative lifetime of up to 1.32 than the reference dye of 1.63, better light harvesting efficiency (LHE), and the highest NBO charge on bridges of designed photosensitizers for enhanced light emitting efficiency. The investigated dyes exhibited more negative values for electron injection, i.e. −0.003 and the highest values of dye regeneration (ΔGregedyeregen) up to 11.717, which unveils innovative and effective injection of electrons toward semiconductor TiO2. Among all dyes, FZB8 proved best with the novel bridging modification that enables quick charge transfer as exhibited the lowest gap (5.17 eV), lowest excitation energy, better LHE, highest charge on LUMO and more negative electron injection (ΔGinject). The outcomes of this computational study confirmed that this research established a new benchmark for achieving novel and efficient photosensitizers, thus recommending them for future DSSC applications. [ABSTRACT FROM AUTHOR]

An organic cathode material for zinc-ion batteries shows a reliable proton transport mechanism. It uses a pyrazine ring as the energy storage unit and H+ as the shuttle ion, enabling high functionality utilization with rapid redox kinetics. [ABSTRACT FROM AUTHOR]

An unexpected nitro group displacement during a nitro-Mannich reaction led to the one-pot formation of the octahydro-2H-pyrazino[1,2-a]pyrazine core, representing the shortest access to date to this pharmacologically relevant heterobicyclic system. A mechanistic hypothesis is suggested and supported by specific experiments and HRMS analysis of reaction mixtures. [ABSTRACT FROM AUTHOR]

This study investigated the composition of the aroma substances and the physicochemical properties of lyophilized coffee produced from Ecuador Arabica and robusta coffee beans. In the present study, we propose a fast method of analyzing volatile compounds in coffee using the headspace solid phase extraction method (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). According to the results, 25 aroma compounds were detected in coffee, the most important of which are 2-acetylfuran, 2-furanmethanol, 2,3-dimethylpyrazine, 2,3,5-trimethylpyrazine, and 2-methoxy-4-vinylphenol. As is known, furans and pyrazines are associated with "roasted, cocoa, coffee, and hazelnut" odours. The most important organic acids detected in the study are citric, maleic, and succinic. [ABSTRACT FROM AUTHOR]

In this study, the volatile flavour compounds of baked potatoes from different cultivars were identified and analysed via headspace–gas chromatography–ion mobility spectrometry (HS-GC-IMS) together with principal component analysis (PCA). Totally, 89 signal peaks were detected, and 64 compounds were identified and classified into 25 aldehydes, 14 alcohols, 11 ketones, 5 esters, 2 furans, 1 pyrazine and others. Based on the signal intensity of the identified compounds, topographic plots and fingerprints were established to investigate the differences caused by cultivars. The main compounds including aldehydes, alcohols, ketones, esters, furan and pyrazine varied with cultivars; they were more abundant in B5 and B6 cultivars. Moreover, PCA and fingerprint similarity analysis clearly showed that these samples are independent and distinguishable. Results also showed that the GC-IMS technique might be helpful and useful in the rapid detection of volatile compounds in cooked potatoes and provide support for the domestic and industrial products. The obtained information could serve for breeding projects of new varieties with specific flavour profiles which comply with consumer demand. [ABSTRACT FROM AUTHOR]

The emergence of extensively drug-resistant Salmonella Typhi (XDR-S. Typhi) poses a grave public health threat due to its resistance to fluoroquinolones and third-generation cephalosporins. This resistance significantly complicates treatment options, underscoring the urgent need for new therapeutic strategies. In this study, we synthesized pyrazine carboxamides (3, 5a–5d) in good yields through the Suzuki reaction. Afterward, we evaluate their antibacterial activities against XDR-S. Typhi via the agar well diffusion method; 5d has the strongest antibacterial activity with MIC 6.25 (mg/mL). Moreover, in vitro Alkaline Phosphatase inhibitor activity was also determined; 5d is the most potent compound, with an IC50 of 1.469 ± 0.02 µM. Further, in silico studies were performed to find the type of interactions between synthesized compounds and target proteins. [ABSTRACT FROM AUTHOR]

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By employing the doorway-window (DW) on-the-fly simulation protocol, we performed ab initio simulations of peak evolutions and beating maps of electronic two-dimensional (2D) spectra of a polyatomic molecule in the gas phase. As the system under study, we chose pyrazine, which is a paradigmatic example of photodynamics dominated by conical intersections (CIs). From the technical perspective, we demonstrate that the DW protocol is a numerically efficient methodology suitable for simulations of 2D spectra for a wide range of excitation/detection frequencies and population times. From the information content perspective, we show that peak evolutions and beating maps not only reveal timescales of transitions through CIs but also pinpoint the most relevant coupling and tuning modes active at these CIs. [ABSTRACT FROM AUTHOR]

Covalent triazine frameworks (CTFs) are promising battery electrodes owing to their designable functional groups, tunable pore sizes, and exceptional stability. However, their practical use is limited because of the difficulty in establishing stable ion adsorption/desorption sites. In this study, a melt‐salt‐stripping process utilizing molten trichloro iron (FeCl3) is used to delaminate the layer‐stacked structure of fluorinated covalent triazine framework (FCTF) and generate iron‐based ion storage active sites. This process increases the interlayer spacing and uniformly deposits iron‐containing materials, enhancing electron and ion transport. The resultant melt‐FeCl3‐stripped FCTF (Fe@FCTF) shows excellent performance as a potassium ion battery with a high capacity of 447 mAh g−1 at 0.1 A g−1 and 257 mAh g−1 at 1.6 A g−1 and good cycling stability. Notably, molten‐salt stripping is also effective in improving the CTF's Na+ and Li+ storage properties. A stepwise reaction mechanism of K/Na/Li chelation with C═N functional groups is proposed and verified by in situ X‐ray diffraction testing (XRD), ex‐situ X‐ray photoelectron spectroscopy (XPS), and theoretical calculations, illustrating that pyrazines and iron coordination groups play the main roles in reacting with K+/Na+/Li+ cations. These results conclude that the Fe@FCTF is a suitable anode material for potassium‐ion batteries (PIBs), sodium‐ion batteries (SIBs), and lithium‐ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

The synthesis of substituted pyrazines from readily available methyl aryl/heteroaryl ketones and 1,2‐diamines was achieved using highly stable and reusable ferrite‐stabilized copper nanoparticles (Fe3O4‐CuO) as a catalyst. The reaction proceeds through a cascade imine formation–oxidative cyclization method under an oxygen atmosphere. The nanocatalysts were readily recovered and reused up to three consecutive cycles without any significant decrease in particle size, catalytic activity and reaction yield, as evidenced by analytical techniques such as transmission electron microscopy (TEM) and powder X‐ray diffraction (PXRD). The synthesized pyrazines exhibited photophysical behaviour, displayed large Stokes shifts, and were explored as fluorescent probes for the sensitive as well as selective "turn‐off" detection of iron with a limit of detection of 0.63 μM. The sensing method is also useful for the quantification of iron in spiked water samples. Furthermore, the application of luminescent pyrazines as fluorescent ink was successfully demonstrated. [ABSTRACT FROM AUTHOR]

High‐efficiency and long‐lifetime near‐infrared (NIR) organic light‐emitting diodes (OLEDs) are rarely reported. Herein, three efficient NIR Ir(III) complexes 1–3 are developed with specially designed cyclometallated ligands based on pyrido[3,4‐b]pyrazine and oriented substitutions along the Ir─N bond axis. Electron‐deficient pyrazine ring effectively stabilizes LUMO energy, leading to significant emission bathochromic shift. Importantly, for complexes 2 and 3, oriented substitutions along the direction of the Ir─N bond axis considerably enhance the horizontal emitting dipole orientation ratio up to 90%. Their OLEDs demonstrate high maximum external quantum efficiencies (EQEs), negligible efficiency roll‐offs, superior radiance, and long lifetimes. The maximum EQEs and radiances of devices are 9.84% and 158 W Sr−1 m−2 at 725 nm for 1, 6.98% and 14.03 W Sr−1 m−2 at 760 nm for 2, and 12.49% and 18.94 W Sr−1 m−2 at 735 nm for 3, respectively. The device lifetime LT97 at 10 mA cm−2 is 453 h for complex 2, which sets a champion lifetime for NIR‐OLEDs. This work demonstrates that pyrido[3,4‐b]pyrazine is a desired building block for robust NIR emitting Ir(III) complexes, providing a superior paradigm to combine high efficiency, negligible roll‐off, and long device lifetime simultaneously toward practical applications. [ABSTRACT FROM AUTHOR]

The market for fine-flavor cocoa provides significant benefits to farmers. However, identifying the sensory qualities of chocolate under specific environmental conditions and measuring how its chemical compounds may be affected by climate differences and postharvesting practices remain a challenge. This study investigates how fermentation time and agroclimatic conditions in Colombia's fine cocoa-producing region of Arauca influence the sensory profile and volatile compound composition (volatilome) of chocolate derived from cocoa beans. Sensory evaluation was conducted on chocolates fermented for 48, 72, 96, and 120 h, revealing that fermentation time critically affects the development of fine-flavor attributes, particularly fruitiness and nuttiness. The optimal fermentation period to enhance these attributes was identified at 96 h, a duration consistently associated with peak fruitiness under all studied climatic conditions. Analysis of 44 volatile compounds identified several key aroma markers, such as acetoin, 1-methoxy-2-propyl acetate, and various pyrazines, which correlate with desirable sensory attributes. These compounds exhibited varying amounts depending on fermentation time and specific agroclimatic conditions, with a 96 h fermentation yielding chocolates with a higher quantity of volatile compounds associated with preferred attributes. Our findings highlight the complex interaction between fermentation processes and agroclimatic factors in determining cocoa quality, providing new insights into optimizing the flavor profiles of chocolate. [ABSTRACT FROM AUTHOR]

π‐Conjugated materials are highly attractive owing to their unique optical and electronic properties. Covalent organic frameworks (COFs) offer a great opportunity for precise arrangement of building units in a π‐conjugated crystalline matrix and tuning of the properties through choice of functionalities or post‐synthetic modification. With this review, we aim at summarizing both the most representative as well as emerging strategies for the synthesis of π‐conjugated COFs. We give examples of direct synthesis using large, π‐extended building blocks. COFs featuring fully conjugated linkages such as vinylene, pyrazine, and azole are discussed. Then, post‐synthetic modification methods that result in the extension of the COF π‐system are reviewed. Throughout, mechanistic insights are presented when available. In the context of their utilization as film devices, we conduct a concise survey of the prominent COF layer deposition techniques reported and their aptness for the deposition of fused aromatic systems. [ABSTRACT FROM AUTHOR]

The applicability of SNH and click reactions in the series of 2-amino-5-bromomethyl-3-(ethoxycarbonyl)pyrazine 1-oxide and its derivatives for the synthesis of distant analogs of folic acid and fluorophores was studied. The target products were synthesized in the yields up to 81%, and their structures were proved by 1H NMR spectroscopy and mass spectrometry. [ABSTRACT FROM AUTHOR]