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Graphene oxide (GO) was used as sorbent in dispersive solid phase extraction (DSPE) to enrich and extract some triazine herbicides from environmental water samples. It can form dispersed colloids in aqueous phase and provides rich functional groups for the formation of hydrogen bonding or π–π electrostatic interaction with benzene ring organic compounds containing oxygen and nitrogen functional groups. GO was synthesised by modified Hummers method and characterised with Fourier transform infrared (FT-IR) spectroscopy. As complete collection of GO after adsorption process is difficult task, in this established salt-assisted (SA)-GO-DSPE method, it was found to be aggregated and centrifuged in the presence of NaCl. The optimum value for main parameters that influenced extraction efficiency were investigated. Under the optimised conditions, low limits of detection (LODs) (0.12–0.80 ng mL −1), limits of quantification (LOQ) (0.4–2.68 ng mL −1), and good extraction recoveries (69.06–95.53%) were obtained for simultaneous extraction of simazine (SIZ), atrazine (ATZ), propazine (PRZ)) and prometryn (PRN). The relative standard deviations (RSD) of intraday (n = 6) and interday (n = 9) precisions were 2.54 to 5.84% and 4.38 to 8.56%, respectively. At the end, the applicability of the method was evaluated and target analytes were not detected in real samples. The proposed method is environment friendly and promising for trace analysis of pesticides including the target herbicides in environmental water samples. [ABSTRACT FROM AUTHOR]

BACKGROUND: Most Phalaenopsis cultivars have almost no aroma, with a few exceptions. Phalaenopsis presents significant challenges in fragrance breeding due to its weak aroma and low fertility. It is therefore necessary to identify the aroma components and key regulatory genes in Phalaenopsis cultivars like 'Orange Beauty', 'Brother Sara Gold', 'Purple Martin', 'H026', 'SK16', 'SX098', and 'SH51', to improve the aroma of the common Phalaenopsis. RESULTS: Floral aroma components were tested on nine Phalaenopsis species, using smell identification and headspace gas chromatography–mass spectrometry. The result showed that alcohols, esters, and alkenes were the key specific components in the different species and cultivar aromas and the aroma intensity and component content of cultivars with different colors were different. The main components of the floral aromas in Phalaenopsis were alcohols (including eucalyptol, linalool, citronellol, and 1‐hexanol), esters (including hexyl acetate, leaf acetate, and dibutyl phthalate), alkenes (including pinene and sabinene) and arenes (like fluorene). The transcriptome of flowers in the bud stage and bloom stage of P. 'SH51' was sequenced and 5999 differentially expressed genes were obtained. The contributions of the phenylpropionic acid/phenyl ring compound and the terpene compound to the aroma were greater. Sixteen genes related to phalaenopsis aroma were found. TC4M, PAL, CAD6, and HR were related to phenylpropanoid synthesis pathway. SLS, TS10, and P450 were related to the synthesis pathway of terpenes. TS10 and YUCCA 10 were involved in tryptophan metabolism. CONCLUSION: This is the first report on the floral aroma components and regulatory genes in Phalaenopsis. The proposed method and research data can provide technical support for Phalaenopsis breeding. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A straightforward, one-pot, three-component reaction between substituted aromatic aldehydes, 2- naphthol and 4- aminoantipyrine have been used to synthesis a series of new 4-(((2-hydroxynaphthalen1-yl) (phenyl) methylene) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one derivatives (A1- A5). This reaction was carried out with zirconyl chloride (ZrOCl2.8H2O) as an efficient catalyst under the condition of ultrasound irradiation. The fact that these derivatives have the potential to act as building blocks in the production of new compounds makes them very essential 4-(1-phenyl-1Hnaphtho[1,2-e] [1,3] oxazin-2(3H)-yl)- 1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one derivatives (A6, A7 and A8). Likewise, the MCRs that resulted in the formation of hetero cyclic compound (1,3-naphthoxazine) and included 4-aminoantipyrine, formaldehyde, and 2-naphthol in a mole ratio of 1:2:1 have been employed to generate 4- (1H-naphtho [1,2-e] [1,3] oxazin-2(3H)-yl)-2- phenyl-1, 5-dimethyl-1,2-dihydro-3H-pyrazol-3-one (A9). This reaction begins with the introduction of ZrOCl2-K2CO3 catalyst system and proceeds through condensation and cyclization. All produced compounds were analyzed through IR, 1H NMR, and 13C NMR spectra data to illustrate each of these distinct structures. Using the broth microdilution and disc diffusion method, the antibacterial and antifungal activities of the compounds were evaluated against Gram-positive, Gram-negative, in comparison to conventional medicines (Ampicillin, Ciprofloxacin and Amoxycilline). The synthesized compounds had a wide range of action, with MIC values of 200, 600 and 1000 µg/ml against the investigated bacteria, as determined by microbiological analysis. [ABSTRACT FROM AUTHOR]

Rate coefficients, k(T), for the gas‐phase OH radical reaction with decamethyltetrasiloxane ((CH3)3SiO[Si(CH3)2O]2Si(CH3)3, L4, k1), dodecamethylpentasiloxane ((CH3)3SiO[Si(CH3)2O]3Si(CH3)3, L5, k2), and decamethylcyclopentasiloxane ([–Si(CH3)2O–]5, D5, k3), and dodecamethylcyclohexasiloxane ([–Si(CH3)2O–]6, D6, k4) were measured using a pulsed laser photolysis—laser induced fluorescence absolute method over the temperature range 270–370 K. The obtained room temperature rate coefficients, with quoted 2σ absolute uncertainties, and fitted temperature dependence are (cm−3 molecule−1 s−1): k1295K=2.50±0.18×10−12,k1270−370K=1.707×10−13T/2984.45exp807/Tk2295K=3.12±0.32×10−12,k2295−370K=2.65±0.02×10−11exp−630±60/Tk3295K=2.02±0.12×10−12,k3270−370K=8.97×10−13T/2982.90exp248/Tk4297K=2.89±0.16×10−12,k4297−370K=3.13±0.05×10−11exp−717±119/T$$\begin{equation*} \hspace*{45pt} \def\eqcellsep{&}\begin{array}{rcl} {k}_1\left( {295\;{\mathrm{K}}} \right) &=& \left( {2.50 \pm 0.18} \right) \times {{10}}^{ - 12},\quad {k}_1\left( {270-370\;{\mathrm{K}}} \right)\\ & =& 1.707 \times {{10}}^{ - 13}{{\left( {{\mathrm{T}}/298} \right)}}^{4.45}\exp \left( {807/{\mathrm{T}}} \right)\\ {k}_2\left( {295\;{\mathrm{K}}} \right) &=& \left( {3.12 \pm 0.32} \right) \times {{10}}^{ - 12},\quad {k}_2\left( {295-370\;{\mathrm{K}}} \right)\\ &=& \left( {2.65 \pm 0.02} \right) \times {{10}}^{ - 11}\exp \left( { - \left( {630 \pm 60} \right)/{\mathrm{T}}} \right)\\ {k}_3\left( {295\;{\mathrm{K}}} \right) &=& \left( {2.02 \pm 0.12} \right) \times {{10}}^{ - 12},\quad {k}_3\left( {270-370\;{\mathrm{K}}} \right)\\ & =& 8.97 \times {{10}}^{ - 13}{{\left( {T/298} \right)}}^{2.90}\exp \left( {248/{\mathrm{T}}} \right)\\ {k}_4\left( {297\;{\mathrm{K}}} \right) &=& \left( {2.89 \pm 0.16} \right) \times {{10}}^{ - 12},\quad {k}_4\left( {297-370\;{\mathrm{K}}} \right)\\ & =& \left( {3.13 \pm 0.05} \right) \times {{10}}^{ - 11}\exp \left( { - \left( {717 \pm 119} \right)/{\mathrm{T}}} \right) \end{array} \end{equation*}$$The 2σ absolute rate coefficient uncertainty, for all compounds included in this study, is conservatively estimated to be ∼10% over the entire temperature range. The cyclic permethylsiloxanes were found to be less reactive than the analogous linear compound, while both linear and cyclic compounds show increasing reactivity with increasing number of CH3‐ groups. A structure activity relationship (SAR) parameterization for the permethylsiloxanes is presented. The estimated atmospheric lifetimes due to OH reaction for L4, L5, D5, and D6 are 5.2, 4.4, 6.8, and 5.2 days, respectively. [ABSTRACT FROM AUTHOR]

The present study involves the synthesis of two energetic compounds that were synthesized by substitution reactions with 5-aminotetrazole. Notably, the representative energetic 2-fluoro-4,6-dinitro-N1,N3-di(1 h-tetrazol-5-yl)benzene-1,3-diamine (ZXC-91) exhibits good density (296 K, 1.807 g cm−3) and good detonation properties (D = 8490 ms−1, p = 31.0 GPa). Additionally, considering other advantages such as simple preparation, cheap raw material, good thermostability (Td = 262.2 °C), and insensitivity (IS = 15 J, FS= 144 N), compound ZXC-91 is an ideal insensitive high energy density materials (HEDMs) candidate. The present study involves the synthesis of two energetic compounds through substitution reactions with 5-aminotetrazole. Today, there is an emerging trend among scientists to incorporate tetrazole rings into energetic compounds. Similarly, the present study involves the synthesis of two energetic compounds that were also synthesized by substitution reactions with 5-aminotetrazole. Notably, the representative energetic 2-fluoro-4,6-dinitro-N1,N3-di(1 h-tetrazol-5-yl)benzene-1,3-diamine (ZXC-91) exhibits good density (296 K, 1.807 g cm−3) and excellent detonation properties (D = 8490 ms−1, p = 31.0 GPa). Additionally, considering other advantages such as simple preparation, cost-effective raw materials, excellent thermostability (Td = 262.2 °C), and insensitivity (IS = 15 J, FS= 144 N), compound ZXC-91 is an ideal insensitive high energy density materials (HEDMs) candidate. [ABSTRACT FROM AUTHOR]

Development of energetic materials with enhanced thermostability and diminished sensitivity is one of the main objectives of current research. In this work, an N,N-alkylidene bridge was used to synthesize a series of tricyclic heat-resistant fused ring compounds. The physical and chemical properties of newly synthesized compounds are verified and quantified through experimental and theoretical methods. The structures of all fused compounds were determined through single-crystal X-ray diffraction, elemental analysis, NMR spectroscopy, and IR spectroscopy. Among these compounds, 9-nitro-5,6-dihydrotetrazolo[1,5-a][1,2,4]triazolo[5,1-c]pyrazine (3) and 10-nitro-6,7-dihydro-5H-tetrazolo[1,5-a][1,2,4]triazolo[5,1-c][1,4]diazepine (4) exhibit excellent thermal stability with the decomposition temperatures higher than 300 °C (3: 301 °C and 4: 311 °C). Furthermore, compounds 3 and 4 are more insensitive in comparison with the applied heat-resistant material HNS (3: IS = 33 J, FS > 360 N; 4: IS > 40 J, FS > 360 N; HNS: IS = 5 J, FS = 240 N). Additionally, compound 3 displays significantly superior detonation properties compared to HNS (3: VD = 8021 m s−1, P = 25.8 GPa; HNS: VD = 7612 m s−1, P = 24.3 GPa). The potential of compound 3 as a heat-resistant material is demonstrated by these experimental and theoretical data. [ABSTRACT FROM AUTHOR]

Seasonings like garlic, ginger, and scallion provide spicy and masking flavor or aroma in vegetables. However, the method or technique used for drying these spices can affect the flavor profile. Therefore, this review focuses on vegetable seasonings like ginger, garlic, and scallion, the characteristic flavor of fresh and dehydrated vegetable seasoning, and how drying methods (freeze‐drying [FD], convective hot air drying [HAD], infrared drying, microwave drying [MW]), and other recent dryers (swirling fluidized bed [SFB], pulsed‐vacuum dryer, relative humidity‐convective dryer, etc.) affect the flavor profile of the common vegetable seasonings. HAD increases α‐zingiberene, reduces gingerol, and forms β‐citral and citral in fresh ginger. FD increased sesquiterpenes, retained terpenoids, sulfides, and other volatiles in fresh ginger, and did not produce new volatile compounds (VOCs) in garlic. SFB drying better preserves 6‐gingerol than FD and HAD. MW increases trisulfides and cyclic sulfur compounds in garlic. In general, drying, especially thermal drying reduces the VOCs in fresh garlic, ginger, and scallion and causes the formation of new VOCs. [ABSTRACT FROM AUTHOR]

Starting from (p‐tolylsulfinyl)ferrocene (1), a mixture of the complete series [CpFe{C5H5–n(SOTol‐p)n}] (n = 2–4) (2–4) in all regioisomers was obtained. After chromatographic separation, crystals of 1,2‐bis[(4‐methylbenzene)sulfinyl]ferrocene, 2a, and 1,3‐bis[(4‐methylbenzene)sulfinyl]ferrocene, 2b, both [Fe(C5H5)(C19H17O2S2)], as well as of 1,2,3‐tris[(4‐methylbenzene)sulfinyl]ferrocene, [Fe(C5H5)(C26H23O3S3)], 3a, and 1,2,3,4‐tetrakis[(4‐methylbenzene)sulfinyl]ferrocene ethyl acetate 0.75‐solvate, [Fe(C5H5)(C33H29O4S4)]·0.75C4H8O2, 4, could be isolated. Their molecular and crystal structures are compared with each other and also with the so far unreported structures of related 1,2‐bis(phenylsulfanyl)ferrocene, [Fe(C5H5)(C17H13S2)], 5, and 1,2,3,4‐tetrakis(phenylsulfanyl)ferrocene, [Fe(C5H5)(C29H21S4)], 6. In all the sulfinyl structures, the O atoms of the S=O groups are in equatorial positions, except for that in tetrasubstituted 4. All the arene rings of these compounds (except for one ring in 4) are in axial positions directed away from the Fe atom, mostly in a near perpendicular orientation with respect to the plane of the cyclopentadienyl ring. The main intermolecular interactions in the crystals are C—H...H—C, C—H...π and C—H...O, while C—H...S interactions are much less important, except for tetrasulfanyl compound 6. π–π interactions (intramolecular) are only important in compound 3a. Hirshfeld analysis shows that dispersion terms are dominant for the interaction energies of all six compounds. In general, the calculated total interaction energies increase with increasing number of substituents and are higher for the sulfinyl than for the sulfanyl groups. [ABSTRACT FROM AUTHOR]

Nucleophilic phosphine-catalyzed annulations are recognized as practical and powerful tools for synthesizing various cyclic compounds. Phosphine acceptors play a key role in nucleophilic phosphine catalysis. The design and synthesis of new phosphine acceptors that are able to introduce new zwitterionic intermediates with new reactivities into phosphine-catalyzed annulations is highly desirable. We recently applied proton-shift principles in the design of new phosphine acceptors, and we synthesized several new acceptors. With the use of these acceptors, we have developed several novel phosphine-catalyzed annulation reactions. In this account, we present a brief introduction to the design and application of a series of acidic-hydrogen-tethered electron-deficient acceptors for phosphine-catalyzed annulation reactions, categorized according to the type of atom (N–H, O–H, C–H) to which the acidic hydrogen is bound. 1 Introduction 2 Phosphine Acceptors Tethered with an Acidic N–H Group 3 Phosphine Acceptors Tethered with an Acidic O–H Group 4 Phosphine Acceptors Tethered with an Acidic C–H Group 5 Conclusions [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Nitrenes, as neutral monovalent nitrogen‐centered molecular species, can insert into various bond or remove nitrogen atoms from amines. Nitrene assisted single‐atom skeletal editing, discovered decades ago, provides an efficient approach for the precise alteration of cyclic skeletons. In this review, we briefly summarize early studies on skeletal editing of cyclic frameworks involving nitrene species, and introduce several recent important advances systematically. [ABSTRACT FROM AUTHOR]

As part of a series of studies of hydrogen‐atom transfer or tautomerization reactions of imidic acid‐amide species, H${\text{H}}$─O${\text{O}}$─C${\text{C}}$═N${\text{N}}$─ ⇌O$\rightleftharpoons {\text{O}}$═C${\text{C}}$─NH${\text{NH}}$─, we report the rate constants for a set of 16 four‐membered cyclic compounds at low, 50–300 K, and high, 500–1500 K, temperatures. The compounds are labeled according to the two ring groups X and Y, which can be CH2${\text{CH}}_{2}$, NH, CH, N, O, or C(O) and which are at some remove from the reactive site. These rate constants are for both the direct reaction and for that mediated by an additional water molecule, which facilitates the hydrogen transfer reaction. In the latter case, we show that the rate of reaction from a pre‐reaction complex is rapid at temperatures down to 50 K and dominated by quantum mechanical effects as evaluated by small‐curvature and quantized‐reaction‐states tunneling. In addition, we present thermochemical data such as enthalpies of formation, entropies, isobaric heat capacities, and enthalpy functions for these largely unknown species, which span a range of compounds from β$\beta$‐propiolactone to 1,3‐diazetidine‐2,4‐dione. [ABSTRACT FROM AUTHOR]

π-Stacking is common in materials, but different π–π stacking modes remarkably affect the properties and performances of materials. In particular, weak interactions, π-stacking and hydrogen bonding often have a significant impact on the stability and sensitivity of high-energetic compounds. A fused [5,7,5]-tricyclic energetic compound with a conjugated structure has been designed and synthesized. 4 H -[1,2,5]Oxadiazolo[3,4- e ][1,2,4]triazolo[3,4- g ][1,2,4]triazepin-8-amine is obtained in 48% yield from 3-amino-4-carboxy-1,2,5-oxadiazole through an efficient two-step reaction. Owing to its layered planar structure and weak π interactions between layers, 4 H -[1,2,5]oxadiazolo[3,4- e ][1,2,4]triazolo[3,4- g ][1,2,4]triazepin-8-amine exhibits high thermal stability (Td = 318 °C), low sensitivity (IS = 40 J, FS = 360 N), and relatively excellent detonation performance (D = 7059 ms–1 , P = 20.2 GPa). This detonation performance is superior to that of the conventional explosive TNT. The developed procedure provides a new method for the synthesis of fused ring compounds. [ABSTRACT FROM AUTHOR]

The presented review systematizes and summarizes the data on the synthesis of pyrrolidine derivatives, which are precursors for obtaining drugs. Based on the analysis of published data, the most promising directions in the synthesis of biologically active compounds containing a pyrrolidine ring are identified. Stereoselective synthesis methods are classified based on the source of the pyrrolidine ring. The first group includes methods that use a pyrrolidine ring as the starting compound. The second group combines stereoselective methods of cyclization of acyclic starting compounds, which lead to optically pure pyrrolidine derivatives. [ABSTRACT FROM AUTHOR]

Cytochrome P450 monooxygenases are recognized as versatile biocatalysts due to their broad reaction capabilities. One important reaction is the hydroxylation of non-activated C–H bonds. The subfamily CYP153A is known for terminal hydroxylation reactions, giving access to functionalized aliphatics. Whilst fatty derivatives may be converted by numerous enzyme classes, midchain aliphatics are seldomly accepted, a prime property of CYP153As. We report here on a new CYP153A member from the genome of the mesophilic actinobacterium Gordonia rubripertincta CWB2 as an efficient biocatalyst. The gene was overexpressed in Escherichia coli and fused with a surrogate electron transport system from Acinetobacter sp. OC4. This chimeric self-sufficient whole-cell system could perform hydroxylation and epoxidation reactions: conversions of C6–C14 alkanes, alkenes, alcohols and of cyclic compounds were observed, yielding production rates of, e.g., 2.69 mM h−1 for 1-hexanol and 4.97 mM h−1 for 1,2-epoxyhexane. Optimizing the linker compositions between the protein units led to significantly altered activity. Balancing linker length and flexibility with glycine-rich and helix-forming linker units increased 1-hexanol production activity to 350 % compared to the initial linker setup with entirely helical linkers. The study shows that strategic coupling of efficient electron supply and a selective enzyme enables previously challenging monooxygenation reactions of midchain aliphatics. [ABSTRACT FROM AUTHOR]

A one‐pot, three‐component reaction of ethyl 5‐aminobenzofuran‐2‐carboxylate, arylglyoxals and cyclic 1,3‐dicarbonyl compounds in the presence of acetic acid as an organocatalyst in ethanol medium under reflux conditions provided a series of new 6H‐furo[3,2‐e]indole derivatives in good yields. [ABSTRACT FROM AUTHOR]

A series of fluorescent carbazole‐coumarins exhibiting good photoluminescence quantum yields and thermally activated delayed fluorescence (TADF) properties have been designed and synthetized using computer‐aided density functional theory calculations. The TADF characteristics of the carbazole‐coumarins were systematically explored both in solution and in the solid state, utilizing poly(methyl methacrylate) (PMMA) as a matrix. The study revealed that the introduction of carbazole units onto the coumarin benzene ring led to compounds with thermally induced reverse intersystem crossing and delayed fluorescence. The study further demonstrated the potential utility of these compounds in practical applications by incorporating them into a Cmr‐PMMA‐based sensor for molecular oxygen detection. The resulting sensor exhibited promising performance, highlighting the adaptability and efficacy of the synthesized TADF‐carbazole‐coumarin compounds for reversible molecular oxygen sensing. [ABSTRACT FROM AUTHOR]

Bisphenols as an important industrial raw material has endocrine disruption, reproductive toxicity, and neurotoxicity. Laccase (Lac) has demonstrated excellent catalytic oxidation performance for phenolic compounds. Micro-nano bubbles (MNB) have been extensively used in wastewater treatment, and the high efficiency of MNB-assisted laccase (MNB-Lac) as a hybrid technique for removing bisphenols from water has been established. In this study, MNB-Lac system was used to degrade bisphenols including bisphenol A (BPA), bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), and bisphenol F (BPF). A comparative analysis was conducted to evaluate the degradation of individual and mixed bisphenols by MNB-Lac. The results indicated that the degradation effect on all individual bisphenols was superior. Notably, BPC consistently demonstrated higher selectivity in the mixed degradation process. In the mixed bisphenol degradation process, a distinct degradation sequence between BPE and BPF was observed. The affinity order of BPA and BPE was found to be inconsistent with their individual degradation order, and the degradation reaction was found to conform to second-order kinetics. By gas chromatography mass spectrometry detection, it was found that the degraded products of BPA, BPB, BPC, BPE, and BPF were ring and chain compounds, and the degradation pathways of the five substances were also maintenance ring structure and direct ring opening. The possible transformation relationship of mixed bisphenols during degradation by MNB-Lac was proposed. Moreover, the industrial application of MNB-Lac was evaluated by increasing the wastewater volume of BPA. [ABSTRACT FROM AUTHOR]

In recent years, Morita‐Baylis‐Hillman (MBH) carbonates have been extensively used in domino reactions for the synthesis of novel cyclic and acyclic compounds. This review highlights the progress made in the last decade in the synthesis of a series of compounds from an uncyclized reaction or annulation of MBH carbonates, which demonstrates that the excellent reactivity and high research value of MBH carbonates as representative substrates in organic synthesis. We hope the summary and understanding of the reactivity of MBH carbonates can inspire chemists to apply these substrates in the design of more efficient domino reactions, which will be beneficial for the organic synthesis and drug chemistry. [ABSTRACT FROM AUTHOR]

Xanthones, a class of polyketide derivatives characterized by a dibenzo‐γ‐pyrone core structure, are aromatic oxygenated cyclic compounds extensively found in nature. They are known for their diverse biological activities, including anti‐Alzheimer, antitumor, and antidiabetic properties, which have spurred extensive research into their therapeutic potential. One of the most significant challenges facing mankind currently is the development of antibiotic resistance in pathogenic microbes making microbial infections increasingly difficult to treat. The formation of biofilms enhances bacterial resistance to antibiotics, immune defenses, and environmental stresses. In this review, we have categorized xanthones, both of biological origin and synthesized, based on their structure and summarized the recent studies on their ability to inhibit Gram‐positive and ‐negative bacteria as well as the various underlying mechanisms that contribute to their microbicidal activity. These mechanisms include inhibition of virulence factors and biofilm formation, interaction with cell membranes, and interference with cell wall synthesis and DNA replication. In addition, we have listed the various methods involved in biofilm inhibition and the structure‐activity relationship of various xanthone molecules, highlighting how xanthone derivatives exhibit increased antibacterial activity. With the growing concern of antibiotic resistance, exploring natural compounds like xanthones to study their interaction with bacterial cells is crucial for identifying new treatment options. [ABSTRACT FROM AUTHOR]

In light of the small ring strain of five/six-membered cyclic ethers, constructing complex molecules via ring-opening reactions has consistently been a highly challenging topic in organic synthesis. Induced by Lewis acids, the charge redistribution in cyclic ethers forms oxonium ylide intermediates, thereby activating the C–O bond and subsequently facilitating nucleophilic attack for ring opening. In recent years, a variety of novel Lewis acids, encompassing those with new metal centers and frustrated Lewis pairs (FLPs), have been effectively utilized to induce the formation of oxonium ylides, offering a diverse array of methods for the ring opening of five/six-membered cyclic ethers. This review conveys the extensive application advancements of diverse Lewis acid types for cyclic ether ring-opening reactions over the past two decades, originating from the perspective of the classification of Lewis acids. Furthermore, the substrate applicability and chemical transformation efficiency of these Lewis acids in the ring-opening reactions of cyclic ethers have also been discussed herein. [ABSTRACT FROM AUTHOR]

New triheteroyclic compounds containing quinazolinone, thiophene, andthiadiazole /thiazolidinone structureswere synthesized and characterized by FT-IR, 1H–NMR, and13C–NMRspectral data. The new compounds' inhibitory activities on urease and acetylcholinesterase were assessed. All triheterocyclic compounds with thiadiazole ring have urease and acetylcholinesteraseinhibitory activities.Especially compound 5a; 3-[(5-(phenylamino)-1,3,4-thiadiazol-2-yl]methyl-2-(thiophen-3-ylmethyl)quinazolin-4(3H)-onehas the best urease inhibition result with 13.30 ± 0.15 µg/mL IC50 value, and it also has the best acetylcholinesterase inhibition with 20.30 ± 0.15 µg/mL IC50 value. [ABSTRACT FROM AUTHOR]

Few studies are concerned with the stabilization of polymers using natural polymeric polyphenols. There are no literature reports on the use of poly(flavonoids) produced by bio-chemical polymerization as stabilizers. The aim of the research was to analyse the stabilizing potential (anti-ageing UV) of poly(catechin) and poly(naringenin) in polymer compositions based on the thermoplastic elastomer of ethylene-norbornene copolymer (TOPAS Elastomer E-140). Poly(flavonoids) were obtained in a polymerization reaction with a cross-linking compound and then introduced into cyclic olefin copolymer TOPAS. For comparison, materials with monomeric catechin and naringenin were also prepared. The scope of research included the thermal analysis of the polymer compositions (Oxidation induction time OIT, Thermogravimetry TG), determination of carbonyl indices and ageing coefficients K (based on changes in mechanical properties) after UV ageing (400 h). In addition, the colour change after ageing of the samples was investigated. Samples containing polymeric forms of catechin and naringenin were more susceptible to degradation than samples with monomeric flavonoids. Inferior stabilizing properties of poly(flavonoids) were associated with steric hindrances and limited availability of hydroxyl groups to provide the antioxidant activity of the polymeric compounds. The work extends the literature data by providing an analysis of the stabilizing effect of synthetic poly(flavonoids) in polymer compositions. [ABSTRACT FROM AUTHOR]

1,2,3,4,5-pentathiepines (PTEs) are naturally occurring polysulfides of increasing scientific interest based on their identified pharmacological activities. Artificial PTEs with N-heterocyclic backbones are efficiently synthesized via mediation by a molybdenum–oxo-bistetrasulfido complex. A common feature of all precursor alkynes successfully used to date in this reaction is the presence of a –CH(OEt)2 group since the previously postulated mechanism requires the presence of one OEt– as the leaving group, and the second must become a transient ethoxonium moiety. This raised the question of whether there really is a need for two, maybe only one, or possibly even zero ethoxy substituents. This research problem was systematically addressed by respective variations in the precursor-alkyne derivatives and by employing one related allene species. It was found that the total absence of ethoxy substituents prevents the formation of PTEs entirely, while the presence of a single ethoxy group results in the possibility to distinctly functionalize the position on the resulting N-heterocyclic pyrrole five ring in the target compound. This position was previously exclusively occupied by an –OEt for all products of the molybdenum-mediated reaction. The allene was applied with similar success as precursor as with the related alkyne. The now-employable significant change in precursor composition gives access to a whole new PTE subfamily, allowing further modulation of (physico)-chemical properties such as solubility, and provides additional insight into the mechanism of PTE formation; it comprises a merely partial validation of the previous hypothesis. The new alkyne precursors and pentathiepines were characterized by a variety of instrumental analyses (NMR, mass spec, UV–vis) and in six cases (one alkyne precursor, one unexpected side product, and four PTEs) by single-crystal X-ray diffraction. Syntheses, isolation procedures, analytical data, and the impact of the findings on the previously proposed mechanism are described in detail herein. [ABSTRACT FROM AUTHOR]

A new cyclic natural compound formed by succinic acid and two alanine amino acid units was isolated from the Tetragonisca angustula honey extract. The chemical structure of 1 was established based on spectroscopic data analysis, including one- (1H and 13C NMR) and two-dimensional NMR techniques (1H-1H-COSY, HSQC and HMBC). A primary culture model previously infected with Neospora caninum was used to evaluate 1 for two time intervals (24 and 72 h), showing a reduction (40-56%) of the number of tachyzoites in the first 24 h and until 72 h, a dose-dependent reduction in parasite proliferation (25-50%). Glial cells treated with 1 did not demonstrate toxicity at concentrations up to 25 ug/mL. Treated and infected cultures showed an increase in NO when compared to control cells in 24 h and 72 h. In silico studies suggest that the new compound may affect DNA synthesis and impair -protein production. [ABSTRACT FROM AUTHOR]

Palladium‐catalyzed thioesterification of (aza)indole‐tethered aryl iodides, Mo(CO)6, and sulfonyl chlorides is reported. A series of C2 thioester‐group substituted indoline‐fused ring compounds are constructed by an intramolecular Heck cyclization and carbonylation chemistry involving N‐(2‐iodobenzoyl)indole. The salient features of this three‐component cascade sequence include the use of solid Mo(CO)6 as the carbon monoxide source and good functional group tolerance. [ABSTRACT FROM AUTHOR]

The reaction of diethyl 2,3-dicyanofumarate with carbo- and heterocyclic 1,3-dicarbonyl compounds resulted in a [3+3] annulation with the formation of condensed diethyl 2-amino-4-cyano-4H-pyran-3,4-dicarboxylates. The cascade transformation involved the Michael addition of the enol form of the CH acid to the double bond of diethyl 2,3-dicyanofumarate followed by the Thorpe–Ziegler cyclization. [ABSTRACT FROM AUTHOR]

An effective method has been developed for the synthesis of unique macrohetero[N,S]cycles 1,4,7(8,9,10,11,12,14)-trithia-2,9(10,11,12,13,14,16)-diazacycloalkane 1,1-dioxides by cyclothiomethylation of sulfonamide with bishydroxydithioalkanes and 1,3,6(7)-oxadithioalkanes in the presence of rare earth metal catalysts. A detailed conformational analysis of 1,4,7-trithia-2,9-diazacycloalkane 1,1-dioxide has been carried out, and the energetically most probable path of cyclic interconversion has been proposed. [ABSTRACT FROM AUTHOR]

Cyclopropenones, possessing Hückel aromaticity, are three-membered cyclic compounds that serve as ideal substrates for C-C bond activation. This paper provides a comprehensive summary of the organic chemical reactions involving cyclopropenones through the β-carbon elimination pathway, thus offering valuable references for the study of transition metal-catalyzed C-C bond activation reactions and the transformation applications of cyclopropenones. [ABSTRACT FROM AUTHOR]

This Perspective analyses the perfluoroalkylation reactions by electron donor‐acceptor (EDA) complexes since 2018, while summarizes, in Tables 123, the vast majority of representative perfluoroalkylation reactions of various classes of organic compounds by EDA complexes and halogen‐bonding interactions. Numerous intriguing reaction methodologies and valuable synthetic instances have emerged. We aim to delve into these new examples comprehensively, while also contemplating the future directions in the field. Subsequent sections will elaborate on the perfluoroalkylation of (hetero)aromatic compounds, carbon‐carbon multiple bonds, perfluoroalkylation of carbonyl compounds, and perfluoroalkylation of isocyanides, covering their synthetic scope and mechanistic insights. 1 Table: Perfluoroalkylation reactions of (hetero)aromatic compounds by EDA complexes.: Entry Substrate Complex Reaction conditions Product Ref. 1 [13] 2 [46] 3 RFI (3 equiv.) KOH (1.5 equiv.) Blue LEDs H2O, Ar, 20 h [47] 4 TEEDA (3 equiv.) CFL (25 W) THF, r.t. RF−I (3 equiv.) [48] 5 ICF2CO2Et (1.3 equiv.) Na2CO3 (1.5 equiv.) DMSO (3 mL) Ar, rt. 427 nm LED, 16 h [49] 6 TMG (2.5 equiv.) RF−I (2.5 equiv.) 23 W CFL, MeCN/Hexf (5 : 1) [42,50] 7 TMG (2.5 equiv.) RF−I (2.5 equiv.) 23 W CFL, MeCN [51] 8 Umemoto's reagent (2 equiv.) N‐methylmorpholine (2.5 equiv.) DMF, r.t. [52] 9 Cs2CO3 (2 equiv.) RF−I (3 equiv.) white light H2O (3 equiv.) DMF, r.t. 2 h [53] 10 4.5 W 450 nm laser CaCl2, MeNO2, 0 °C [3] 11 RF−I (1.5 equiv.) t‐BuONa (2 equiv.) DMF Green LEDs [54] 12 or EDA complex I−Rf (2.1 equiv.) TMEDA (2 equiv.) or DBU (2 equiv.) Blue LEDs 24 W [55,56] 13 TFE/water (1 : 1) (0.2 M) CF3SO2Na Blue LEDs r.t. 12 h [84] 2 Table: Perfluoroalkylation reactions of carbon‐carbon multiple bonds and constrained cyclic compounds by EDA complexes.: Entry Substrate Complex Reaction conditions Product Ref. 1 Bu4NCl, Hg lamp (6 W) RF−I (1.2 equiv.) CH3OH, 1.5 h r.t, Ar [39] 2 RFI (3 equiv.) KOH (1.5 equiv.) Blue LEDs H2O, Ar, 20 h [47] 3 [57] 4 DIPEA or TMEDA or DBU or TEEDA ........CF3I CF3−I (3 equiv.) Base (2 equiv.) MeCN or DMF or THF CFL, 25 W with DIPEA, TMEDA or TEEDA; with DBU [48,58,59] 5 Bn2NH MeCN RF−I Blue LED, r.t. [60] 6 Base, Blue LEDs DMF or THF [61] 7 I−RF H2O/toluene=9 : 1 Blue LEDs, 65 °C, 12 h [41] 8 K3PO4 (3 equiv.) RF−I (3 equiv.) CuCl (10 mol%) TMSNCS (3 equiv.) CH3CN (2 mL) Violet LEDs (24 W) Ar, 4 h [37] 9 RF−I (3 equiv.) Diphenylacetaldehyde (10 mol%) Pyrrolidine (40 mol%) DIPEA (2 equiv.) DCE (2.5 mL); O2 (0.8 eq.); Ar White LEDs (2.5 W); 24 h [44,62] 10 DIPEA,DMA Ar (trace air) Blue LEDs, rt. 36–72 h [63] 11 TMEDA Blue LEDs n‐C4F9I DMSO air, 24 h RT [64] 12 K3PO4 (2 equiv.) DABCO (1.2 equiv.) hυ (400 Watt) 50 °C CnF2n+1I (1.8 equiv.) [65–67] 13 Blue LEDs DCE, r.t. [27] 14 2,4,6‐trimethylpyridine MeCN, 60 °C Togni's reagent [68] 15 PMDETA (2 equiv.) DMSO (2 mL) N2, Blue LEDs [69] 16 Blue LEDs [70,71] 17 MeCN (0.2 M) with less than 1 % water CF3SO2Na (1 mmol) Blue LEDs [84] 3 Table: Perfluoroalkylation of carbonyl compounds, isocyanides and hydrazones.: Entry Substrate Complex Reaction conditions Product Ref. 1 [72,73] 2 RF−I (0.2 mmol) cis‐catalyst M (20 mol%) 2,6‐lutidine (1.2 equiv.) Blue LEDs, Et2O (0.7 M) ‐10 °C, 20 h [74] 3 white light RF−I [75] 4 phase transfer catalyst Cs2CO3, C6H5Cl/8F18 (2 : 1), 25 °C, RF−I [32] 5 ambient light C4F9−I NaOH (4.1 equiv.) MeCN, R.T. [76] 6 RFI (3 equiv.) KOH (1.5 equiv.) Blue LEDs THF, Ar, 36 h [47] 7 RF−I (2 equiv.) TMEDA (2 equiv.) THF (2 mL) Blue LEDs (25 W) 30 °C, N2 [77] 8 TEEDA (1.5 equiv.) CFL (25 W) THF I−C4F9 [48] 9 Bn2NH Blue LEDs MeCN, RT RF−I [78] 10 TMG (1.5 equiv.) ambient light MeCN, RT I−RF [79] 11 Imidazole (3 equiv.) MeCN, RF−I (2 equiv.) r.t. [80] [ABSTRACT FROM AUTHOR]

3-Methyl indanones are key synthetic building blocks for a variety of natural and useful synthetic compounds. Their synthesis is exceedingly difficult. Herein, we described a palladium (II) mediated intramolecular one-pot redox-relay cyclization of aromatic homoallylic alcohols to cyclic keto compounds. This catalytic system enabled direct conversion of homoallylic alcohols to corresponding indanones (3-methyl-1-indanones). Homoallylic alcohols were synthesized by reacting allyl magnesium bromide with corresponding aromatic aldehydes. The optimized reaction yielded up to 88% 3-methylindanones. Our findings enabled us to device a plausible mechanism for this one pot reaction. [ABSTRACT FROM AUTHOR]

As part of a series of studies of hydrogen‐atom transfer or tautomerization reactions of imidic acid–amide species, H─O═C─N─⇌O═C─N─H${\rm H\bond O\dbond C\bond N\bond} \rightleftharpoons {\rm O\dbond C\bond N\bond H}$, we report the rate constants for a set of 24 five‐membered cyclic compounds at low, 50–300 K, and high, 500–1500 K, temperatures. These rate constants are for both the high temperature direct reaction and for that mediated by an additional water molecule which facilitates the hydrogen transfer reaction at low temperatures. In the latter case we show that the rate of reaction from a pre‐reaction complex can be rapid at temperatures down to 50 K on a 1 ms timescale and is dominated by quantum mechanical effects as evaluated by small‐curvature and quantised‐reaction‐states tunnelling. In addition, we present thermochemical data such as enthalpies of formation, entropies, isobaric heat capacities and enthalpy functions for these largely unknown species which span a range of compounds from pyrolidinone to oxo‐tetrazoles. [ABSTRACT FROM AUTHOR]

Unsaturated cyclic terpenes often exhibit instability due to the proximation of C=C bonds in the cyclic skeleton, leading to nonenzymatic degradation. In this study, the crystalline sponge (CS) method was employed for the X‐ray conformational analysis of a minute amount of oily and cyclic terpene compound, (+)‐germacrene D‐4‐ol, which was produced by a terpene synthase OILTS under in vitro conditions. The CS method revealed a reactive conformation of the cyclic terpene with proximal double bonds. Under weakly acidic in vivo conditions, OILTS gave four pseudo‐natural products or artifacts. The CS method also elucidated the structures of these degraded compounds, proposing a degradation mechanism triggered by the transannular reactions. [ABSTRACT FROM AUTHOR]

A comprehensive study of the different classes of cycloaddition reactions ([3+2], [2+2], and [2+1]) of SO2 to acetylene and ethylene has been performed using density functional theory (DFT) and composite wavefunction methods. The [3+2] cycloaddition reaction, that was previously explored in the context of the cycloaddition of thioformaldehyde S‐methylide (TSM) to ethylene and acetylene, proceeds in a concerted way to the formation of stable heterocycles. In this paper, we extend our study to the [2+2] and [2+1] cycloadditions of SO2 to acetylene, which would produce 1,1‐oxathiete‐2‐oxide and thiirene‐1,1‐dioxide, respectively. One of the main conclusions is that cyclic 1,1‐oxathiete‐2‐oxide can open through a relatively easy breaking of the SO single bond and rearrange toward sulfinyl acetaldehyde (SA). The SA molecule can easily undergo several internal rearrangements, which eventually lead to sulfenic acid and sulfoxide derivatives of ethenone, 1,2,3‐dioxathiole, and CO plus sulfinylmethane. The most probable path, however, produces 2‐thioxoacetic acid, whose derivatives (or those of the corresponding acetate) are usually obtained by Willgerodt–Kindler‐type sulfuration of acetates. This product can in turn decompose, leading to the final products CO2 and H2CS. Comparison of this decomposition path with that of 2‐amino‐2‐thioxoacetic acid shows that the process occurs through different H‐transfer processes. [ABSTRACT FROM AUTHOR]

Novel chalcones containing a carbazole ring were prepared through the condensation process between 9-ethyl-3-carbazolecarboxaldehyde and 2-acetyl-5-bromothiophene and 3-acetyl-2,5-dimethyl thiophene by the Claisen-Schmidt method, and heterocyclic pyrazoline rings, were also synthesised using hydrazine and its derivatives. The compounds were identified using IR spectroscopy, 13C-NMR, and 1 H-NMR techniques. Chalcones exhibit significant anticancer activity, particularly against colon cancer cells. In a study involving three cancer cell lines, A-549 (lung cancer), MCF-7 (breast cancer), and HCT-116 (colon cancer), chalcones demonstrated the highest efficacy against HCT-116 cells. Specifically, compound L2 showed an IC-50 of 0.58 μM, and compound Lb had an IC-50 of 0.6 μM. Additionally, derivatives of chalcones and heterocyclic pyrazoline ring compounds were also tested for their anticancer potential. A comparative analysis revealed that chalcones were more effective against colon cancer cells, with compound L10 displaying an IC-50 of 37.38 μM and compound L20 an IC-50 of 6.00 μM. [ABSTRACT FROM AUTHOR]

fter reviewing a number of researches that demonstrate the effectiveness of a number of compounds containing the acetylenic amine group as antimicrobials and antiproliferative activity, our goal is to prepare new acetylenic amine derivatives from the compound 2-(2-((2,6- dichlorophenyl)amino)phenyl)acetic acid using the Mannich reaction by the react salt of a carboxylic acid with propargyl bromide to produce the compound (prop-2-yn-1-yl 2-(2-((2,6- dichlorophenyl)amino)phenyl)acetate) (1), which was refluxed with a number of secondary amines and formaldehyde in presence of the copper chloride as a catalyst to obtain 7 compounds (4-(dialkylamino)but2-yn-1-yl 2-(2-((2,6-dichlorophenyl)amino)phenyl)acetate)(2-8). The physical and spectral properties of the prepared compounds were measured, and the bioassay conducted for some substances by investigating their antibiotic activity. The two compounds (1,2) were also selected to test their anticancer activity against one of its types, a breast cancer cell line (MCF-7), using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using multiple concentrations compared to the normal cell line (WRL-68). The previous results showed the effect of the two compounds on the cancer cell line more than its effect on the normal cell line, the results showed significant differences (p≤0.0001) by calculating the (IC50) when treating compounds (1,2) for MCF-7 cancer cells at (250,300) µg/ml and for normal cells at (983,1292) µg/ml respectively. It is believed that the reason for its effectiveness is because contains acetylenic amine in compound (1) in addition to morpholine ring in compound (2), which research has proven to be effective in multiple medicines. Some pharmacokinetic activities of the prepared compounds have been predicted to support the discovery of new drugs using the Swiss ADME website. [ABSTRACT FROM AUTHOR]

The present work reports experimental data on the thermal conductivity of the four hydrocarbons cyclohexane, n-decane, n-hexadecane, and squalane in the liquid state at ambient pressure up to temperatures of 353.15 K. Absolute measurements were performed with a steady-state guarded parallel-plate instrument (GPPI) with an average expanded (coverage factor k = 2) measurement uncertainty of 2 %. For the linear alkanes n-decane and n-hexadecane as well as the cyclic compound cyclohexane, the measured thermal conductivities agree with reference correlations in the literature, indicating the reliability of the technique used for the study of fluids with relatively low thermal conductivities and weak absorption of radiation. For the first time, experimental data are determined for the long-branched alkane squalane between (278 and 353) K, which cannot be accurately represented with estimation methods commonly used in the literature. In summary, the present measurement results confirm the existing database for representative linear and cyclic hydrocarbons and provide first experimental thermal conductivities for squalane. [ABSTRACT FROM AUTHOR]

This article discusses the synthesis, characterization, molecular docking, and antibacterial properties of tetrahydrobenzo[a]xanthene-11-ones. It highlights the use of multicomponent reactions (MCRs) in drug synthesis, which offer economic and ecological benefits. The article presents an efficient and environmentally friendly protocol for synthesizing these compounds and evaluates their antimicrobial activities. Molecular docking simulations were performed to analyze the interactions between the compounds and bacterial DNA-gyrase, and the results showed that the compounds interacted with the enzyme through hydrophobic interactions and hydrogen bonds. The synthesized compounds showed moderate antibacterial activity and could be potential starting points for the development of new compounds. [Extracted from the article]

This article explores the use of 2,2'-bipyridine as a catalyst for the synthesis of 2-amino-4H-pyrans through a one-pot multicomponent reaction. The catalyst was found to be effective, providing high yields of the products, short reaction times, and mild reaction conditions. The catalyst was also shown to be reusable, maintaining its catalytic activity even after multiple runs. The method was compared to other reported methods and found to offer advantages such as shorter reaction times and higher yields. The article includes detailed information on the procedure and characterization of the synthesized compounds and was supported by the University of Guilan Research Council. [Extracted from the article]

A series of pyrrolo[3,2‐f]quinoxaline derivatives have been obtained by a three‐component domino reaction of quinoxalin‐6‐amine, arylglyoxal monohydrates, and cyclic 1,3‐dicarbonyl compounds in ethanol medium at 80°C catalyzed by acetic acid. The notable features of this synthesis are excellent regioselectivity, operational simplicity, relatively mild reaction conditions, and good yields. [ABSTRACT FROM AUTHOR]

We studied the effects of some nitrogen-containing, heterocyclic, and cyclic compounds on the rate of oxidative deamination of polyamines and putrescine in tissues with a high proliferation rate. For this purpose, the specific activities of the main enzymes of polyamine oxidative degradation — spermine oxidase (SMO), polyamine oxidase (PAO), and diamine oxidase (DAO) were determined using a cell-free test system from regenerating rat liver. The compounds methyl 2-(5-formylfuran-2-yl)benzoate and 2,7-bis-[2-(diethylamino)ethoxy]-9H-fluoren-9-one (and in the form of dihydrochloride) showed mainly activating effect on oxidative degradation of putrescine, spermidine, and spermine, which indirectly indicates their antiproliferative effect. Nitrogen-free compounds inhibited this process, thus exhibiting potentially carcinogenic properties. Correlations were calculated for activity of DAO, PAO, and SMO with 5 topological indices: Wiener (W), Rouvray (R), Balaban (J) in the Trinaistich modification, detour (Ip), and electropy (Ie). The highest dependence was noted for DAO and the Balaban index (R=-0.55), for PAO and the detour index (R=0.78), and for SMO and the electropy index (R=0.53). The remaining dependencies showed insignificant correlation strength. [ABSTRACT FROM AUTHOR]

This article discusses the synthesis of 7a-substituted pyrrolizidine derivatives through stereocontrolled anionic cyclization. The derivatives have potential therapeutic applications and the authors describe a new route for their synthesis using proline derivatives and epichlorohydrin. The compounds were successfully synthesized with controlled stereochemistry and characterized using spectroscopic techniques. The text provides detailed information on the reactions, yields, physical properties, and spectroscopic data of the compounds, making it a valuable resource for researchers studying organic chemistry and chemical synthesis. [Extracted from the article]

This article explores the use of cyanophosphates as synthetic intermediates in the transformation of benzaldehydes into benzonitriles. The researchers found that certain benzaldehydes reacted with tetrabutylammonium azide to form aromatic nitriles, while ketone or aliphatic aldehyde cyanophosphates resulted in the formation of tetrabutylammonium ethyl phosphates. The study also investigated the effects of reaction conditions on the transformation process. The document provides detailed information on the synthesis and characterization of various cyano(phenyl)methyl diethyl phosphate compounds, including their isolation methods and spectroscopic data. Additionally, the document includes chemical data for other compounds, such as tetrabutylammonium 3-(tert-Butyldimethylsiloxy)-17-cyanoestra-1,3,5(10)-trien-17-yl Ethyl Phosphate and 3-nitrobenzonitrile, along with their synthesis and purification methods. The authors express gratitude to their colleagues for their support and assistance. [Extracted from the article]

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Since the discovery of metal-catalyzed azide–alkyne cycloadditions, 1,2,3-triazoles have been widely used as linkers for various residues. 1,2,3-Triazole is an aromatic five-membered cyclic compound consisting of three nitrogen and two carbon atoms with large dipoles that absorb UV light. In the past decade, we have been working on the synthesis of dense triazole polymers possessing many 1,2,3-triazole residues linked through a carbon atom in their backbone as a new type of functional polymer. Recently, we reported that stereoregular dense triazole uniform oligomers exhibit a circular dichroism signal based on the chiral arrangement of two neighboring 1,2,3-triazole residues. In this study, to investigate the chiral conformation of two neighboring 1,2,3-triazole residues in stereoregular dense triazole uniform oligomers, density functional theory (DFT) calculations were performed using 1,2,3-triazole diads with different substitution positions and conformations as model compounds and compared with our previous results. [ABSTRACT FROM AUTHOR]

A Cu‐catalyzed vinylation method for alkenyl ethers has been developed. In this strategy, both chain and cyclic alkenyl ether substrates were applicable, and the target products were obtained in up to 95% yields and with the E/Z selectivities of >98:2. Furthermore, we have successfully applied this method to directly vinylate the C‐2 position of protected glucals, offering a valuable tool for their functionalization. Moreover, through the utilization of alkenyl alcohols as substrates, we accomplished a 1,2‐alkenyloxylation of alkenyl double bond, enabling the synthesis of functionalized cyclic ether compounds with five or six‐membered rings. [ABSTRACT FROM AUTHOR]

This article provides an overview of recent advancements in quinoline-based macrocycles, which are large ring-shaped compounds with various applications. The focus is on nitrogen-containing macrocycles, such as porphyrins, and their functional properties, including photophysical characteristics, host-guest chemistry, and catalytic reactions. The authors specifically discuss three quinoline-based macrocycles: TriQuinoline (TQ), oxa-TriQuinoline (o-TQ), and TEtraQuinoline (TEQ), examining their structures, synthesis, and properties. The article also explores potential applications of these macrocycles in DNA intercalation, catalytic dehydrogenative oxidation, and gem-difluoroalkenylation reactions. Furthermore, the article delves into the synthesis and properties of tetrameric quinoline macrocycles (TEQ), which have a rigid saddle-shaped structure and can form metal complexes with transition metal cations. The authors also discuss modifications of TEQ and its fluorescence properties. Additionally, the article touches on larger quinoline-based macrocycles with bridges and their synthesis, highlighting their potential applications in organometallic chemistry and supramolecular chemistry. Overall, the chemistry of quinoline macrocycles is an evolving field with opportunities for further research and applications. [Extracted from the article]

This article discusses the synthesis and characterization of various 1-thiaphenalene derivatives using a radical approach and photoredox catalysis. The reaction involves the intermolecular cyclization of 1-naphthalenesulfonyl chlorides and alkynes under mild conditions, resulting in high product diversity and broad functional-group tolerance. The authors provide a plausible reaction mechanism and experimental details for the synthesis of specific compounds, which were characterized using techniques such as NMR, HRMS, and IR spectroscopy. This information can be valuable for researchers studying these compounds or related topics. [Extracted from the article]

Musks, the foundation of many perfumes, as well as other ingredients of perfumes, were critical objects of study for establishing theoretical concepts about large ring chemical compounds and polymerization in the 1920s and 1930s. Because fragrance chemistry has been underdeveloped in the historiography, doubtless partly because it has become associated with the feminine, this has been ignored in the historiography. This essay highlights the strategic importance of perfume research, looking in particular at the work of Leopold Ružičkač, 1939 Nobel laureate in chemistry who had close ties to the fragrance industry, and Wallace Carothers at DuPont, whose well-known work on polymerization was intimately concerned with large ring compounds, including musk, and which indeed led to DuPont producing a synthetic musk in the 1930s. [ABSTRACT FROM AUTHOR]

Summary: Fermentation of yellow maize using different inocula yields mahewu products with varying compositions. Comprehensive analysis of the metabolites influencing distinctive characteristics of mahewu from sorghum malt (YMSM); wheat (YMW), malted millet (YMMM) and malted yellow maize (YMYM) inocula was investigated using an untargeted gas chromatography high‐resolution time‐of‐flight mass spectrometry (GC‐HRTOF‐MS)‐based metabolomics. Metabolites in mahewu from different inocula included phenols, fatty acid methyl ester (FAME), benzenes, amides, amines, cyclic compounds, fatty acid ethyl esters (FAEEs), esters, ketones and vitamins which differentiated metabolites identified in raw yellow maize (RYM). Principal component analysis (PCA) showed that the mahewu and related inocula were distinguished across PC1 and PC2. The OPLS‐DA result further intensifies the significant (P ≤ 0.05) metabolite causing variations among samples. This study serves as the first report into the metabolome of yellow maize mahewu from different inocula, serving as a foundation for the quality control of mahewu products for further research. [ABSTRACT FROM AUTHOR]

The application of polyesters as food contact materials is an alternative to epoxy resin coatings, which can be a source of endocrine migrants. By using high-pressure liquid chromatography/electrospray ionization–mass spectrometry (HPLC/ESI-MS) with cone voltage-induced fragmentation in-source, a number of polyester-derived migrants were detected in the extracts of inner coatings of metallic cans. The polyester-derived migrants were detected in each inner coating of fish product-containing cans (5/5) and in one inner coating of meat product-containing can (1/5). They were not detected in the inner coatings of vegetable/fruit product-containing cans (10 samples). The respective detected parent and product ions enabled differentiation between cyclic and linear compounds, as well as unambiguous identification of diol and diacid units. Most of the detected compounds, cyclic and linear, were composed of neopentyl glycol as diol and two diacid comonomers, namely isophthalic acid and hexahydrophthalic acid. The other detected oligoesters were composed of neopentyl glycol or propylene glycol and adipic acid/isophthalic acid as comonomers. The compounds containing propylene glycol as diol were found to be exclusively linear cooligoesters. On the basis of abundances of [M+Na]+ ions, the relative contents of cyclic and linear oligoesters were evaluated. [ABSTRACT FROM AUTHOR]