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We have developed a straightforward electrochemical protocol for direct α-amidation and α-pyrazolation of N-alkoxy- and N-aryloxycarbonyl pyrrolidines with amides or pyrazoles. Unlike previously reported methods, this protocol does not require pre-prepared amidation reagents, thereby shortening the synthesis route and boosting atom economy. Various functional groups are tolerated, and the reaction proceeds at room temperature in only 2.5 h without assistance from chemical oxidants or catalysts. [ABSTRACT FROM AUTHOR]

The construction of C(sp3)−N bonds via direct N‐centered radical addition with olefins under benign conditions is a desirable but challenging strategy. Herein, we describe an organo‐photocatalytic approach to achieve anti‐Markovnikov alkene hydroamidation with sulfonyl azides in a highly efficient manner under transition‐metal‐free and mild conditions. A broad range of substrates, including both activated and unactivated alkenes, are suitable for this protocol, providing a convenient and practical method to construct sulfonylamide derivatives. A synergistic experimental and computational mechanistic study suggests that the additive, Hantzsch ester (HE), might undergo a triplet‐triplet energy transfer manner to achieve photosensitization by the organo‐photocatalyst under visible light irradiation. Next, the resulted triplet excited state 3HE* could lead to a homolytic cleavage of C4−H bond, which triggers a straightforward H‐atom transfer (HAT) style in converting sulfonyl azide to the corresponding key amidyl radical. Subsequently, the addition of the amidyl radical to alkene followed by HAT from p‐toluenethiol could proceed to afford the desired anti‐Markovnikov hydroamidation product. It is worth noting that mechanistic pathway bifurcation could be possible for this reaction. A feasible radical chain propagation mechanistic pathway is also proposed to rationalize the high efficiency of this reaction. [ABSTRACT FROM AUTHOR]

The construction of C(sp3)−N bonds via direct N‐centered radical addition with olefins under benign conditions is a desirable but challenging strategy. Herein, we describe an organo‐photocatalytic approach to achieve anti‐Markovnikov alkene hydroamidation with sulfonyl azides in a highly efficient manner under transition‐metal‐free and mild conditions. A broad range of substrates, including both activated and unactivated alkenes, are suitable for this protocol, providing a convenient and practical method to construct sulfonylamide derivatives. A synergistic experimental and computational mechanistic study suggests that the additive, Hantzsch ester (HE), might undergo a triplet‐triplet energy transfer manner to achieve photosensitization by the organo‐photocatalyst under visible light irradiation. Next, the resulted triplet excited state 3HE* could lead to a homolytic cleavage of C4−H bond, which triggers a straightforward H‐atom transfer (HAT) style in converting sulfonyl azide to the corresponding key amidyl radical. Subsequently, the addition of the amidyl radical to alkene followed by HAT from p‐toluenethiol could proceed to afford the desired anti‐Markovnikov hydroamidation product. It is worth noting that mechanistic pathway bifurcation could be possible for this reaction. A feasible radical chain propagation mechanistic pathway is also proposed to rationalize the high efficiency of this reaction. [ABSTRACT FROM AUTHOR]

An iron‐catalyzed protocol for the synthesis of 3‐amino‐3‐aminomethyl‐2‐oxindole heterocyclic structures is disclosed employing isatins and non‐nucleophilic N‐methoxybenzamides. This reaction class is associated with broad scope and tolerates numerous functionalities, such as fluoro, chloro, bromo, iodo, trifluoromethyl, nitrile, ester, ether, and alkenyl, including heteroaryl – thiophene, benzothiophene, carbazolyl, indolyl, eugenol, and polycyclic cholesterol moieties. Detailed mechanistic investigations reveal that the reaction proceeds via iron‐catalyzed N−O bond cleavage in N‐methoxybenzamides, generating formaldehyde and benzamide, and through the intermediacy of isatin‐ketimines and N‐(hydroxymethyl)benzamides. Overall, this amidation reaction involves one C−C and two C−N bond‐forming tandem processes, providing a range of β‐amino‐aminomethyl‐oxindoles (45 examples) in up to 88% yields. [ABSTRACT FROM AUTHOR]

A comprehensive vision has been promoted for straightforward oxidative amidation, deploying a majority of amines and aldehydes via a robust and novel nano-catalyst of W/Co@g-C3N4. This approach would yield the primary, secondary, and tertiary amides with excellent efficiency experiencing mild conditions, in which the environmentally benign oxidizing agent of TBHP was predominantly used, holding remarkable attributes such as cost-effectiveness as well as facile approachability. More specifically, simultaneously embedding of W and Co on the surface of g-C3N4 has been an integral part in effectually progressing direct operation of amidation reaction in comparison with pure g-C3N4. The most important point highlighted in this work is the productive contribution of materials choice in designing as well as manufacturing approaches with respect to new required products while giving the most extreme level of accessible quality and efficiency with the most reduced level of costs. Emphatically, a variety of extraordinary merits can be awarded to this as-prepared catalyst, such as notable activity, reasonable recyclability, sustainable nature, and easy work-up. Moreover, a simple process was conducted to synthesize W/Co@g-C3N4 evaluated by employing FT-IR, XRD, SEM, EDX, and TGA. Highlights: Nano-W/Co@g-C3N4 was introduced for the first time as a robust and efficient catalyst. Employing of tungsten and cobalt revealed a considerable shift in the catalytic performance of g-C3N4. Short reaction time as well as high yield with respect to the reported literatures for formation of amide bond through direct oxidative amidation. W/Co@g-C3N4 could be used in five consecutive runs without any significant drop in activity. [ABSTRACT FROM AUTHOR]

Rh-catalyzed three-component C(sp3)/C(sp2)–H activation has been achieved through a two-directing group strategy. This protocol provides a convenient and efficient pathway for the construction of diverse 8-alkyl quinoline derivatives in one-pot. Furthermore, mechanistic studies revealed that the first C–H amidation was significantly faster than the sequential C–H alkylation. [ABSTRACT FROM AUTHOR]

Amidation is a cornerstone for a plethora of industrially and biologically relevant molecules, yet conventional methods often suffer from inefficiency and poor atom economy. In response, we introduce boric acid-grafted biochar (BoAB) for the synthesis of amides from unactivated acids and amines under mild conditions. BoAB, derived from biomass, offers sustainability, and recyclability with its bifunctional design to produce amides in high yields across diverse substrates. The catalyst showed good turnover with minimal degradation over several reaction cycles. [ABSTRACT FROM AUTHOR]

This document provides a series of chemical data for various compounds, including their yields, physical properties, and spectroscopic data. The compounds described include N-(m-tolyl)benzamide, N-(p-tolyl)benzamide, N-(4-bromophenyl)-N,3-dimethylbenzamide, N-(4-bromophenyl)-N-methylfuran-2-carboxamide, N-methyl-N-(m-tolyl)furan-2-carboxamide, N-methyl-N-(m-tolyl)thiophene-2-carboxamide, N-(4-bromophenyl)-N-methylthiophene-2-carboxamide, N,N-diethylbenzamide, N-ethyl-N-phenylbenzamide, and (3,4-dihydroisoquinolin-2(1H)-yl)(phenyl)methanone. The data provided can be used by researchers studying these compounds for various purposes. [Extracted from the article]

Herein, multiple types of chiral Os(II) complexes have been designed to address the appealing yet challenging asymmetric C(sp3)−H functionalization, among which the Os(II)/Salox species is found to be the most efficient for precise stereocontrol in realizing the asymmetric C(sp3)−H amidation. As exemplified by the enantioenriched pyrrolidinone synthesis, such tailored Os(II)/Salox catalyst efficiently enables an intramolecular site‐/enantioselective C(sp3)−H amidation in the γ‐position of dioxazolone substrates, in which benzyl, propargyl and allyl groups bearing various substituted forms are well compatible, affording the corresponding chiral γ‐lactam products with good er values (up to 99 : 1) and diverse functionality (>35 examples). The unique performance advantage of the developed chiral Os(II)/Salox system in terms of the catalytic energy profile and the chiral induction has been further clarified by integrated experimental and computational studies. [ABSTRACT FROM AUTHOR]

Herein, multiple types of chiral Os(II) complexes have been designed to address the appealing yet challenging asymmetric C(sp3)−H functionalization, among which the Os(II)/Salox species is found to be the most efficient for precise stereocontrol in realizing the asymmetric C(sp3)−H amidation. As exemplified by the enantioenriched pyrrolidinone synthesis, such tailored Os(II)/Salox catalyst efficiently enables an intramolecular site‐/enantioselective C(sp3)−H amidation in the γ‐position of dioxazolone substrates, in which benzyl, propargyl and allyl groups bearing various substituted forms are well compatible, affording the corresponding chiral γ‐lactam products with good er values (up to 99 : 1) and diverse functionality (>35 examples). The unique performance advantage of the developed chiral Os(II)/Salox system in terms of the catalytic energy profile and the chiral induction has been further clarified by integrated experimental and computational studies. [ABSTRACT FROM AUTHOR]

A one‐pot protocol for the synthesis of amides has been developed by employing acetonitrile as nitrogen source and solvent. The reaction undergoes ring‐opening of cyclopropyl carbinols and in situ formation of homoallylic carbocation, which reacts with acetonitrile to give desired products. The substrate of this reaction is widely applicable and the desired products are obtained in moderate to good yields. [ABSTRACT FROM AUTHOR]

The article discusses a method for synthesizing amide bonds using deoxyfluorinated carboxylic acids and pyridinesulfonyl fluoride. The authors optimized the reaction conditions and explored the substrate scope, demonstrating the versatility and utility of their method. They also showcase the application of this methodology in the synthesis of a challenging ester-linked compound and a tetrapeptide. The research was supported by various funding sources, and there are no conflicts of interest to declare. This article provides valuable information for researchers in the field of medicinal chemistry and organic synthesis. [Extracted from the article]

AbstractGlutamine amidotransferases (GATs) catalyze the synthesis of nucleotides, amino acids, glycoproteins and an enzyme cofactor, thus serving as key metabolic enzymes for cell proliferation. Carbamoyl-phosphate synthetase, Aspartate transcarbamoylase, and Dihydroorotase (CAD) is a multifunctional enzyme of the GAT family and catalyzes the first three steps of the de novo pyrimidine synthesis. Following our findings that cellular GATs are involved in immune evasion during herpesvirus infection, we discovered that CAD reprograms cellular metabolism to fuel aerobic glycolysis and nucleotide synthesis via deamidating RelA. Deamidated RelA activates the expression of key glycolytic enzymes, rather than that of the inflammatory NF-κB-responsive genes. As such, cancer cells prime RelA for deamidation via up-regulating CAD activity or accumulating RelA mutations. Interestingly, the recently emerged SARS-CoV-2 also activates CAD to couple evasion of inflammatory response to activated nucleotide synthesis. A small molecule inhibitor of CAD depletes nucleotide supply and boosts antiviral inflammatory response, thus greatly reducing SARS-CoV-2 replication. Additionally, we also found that CTP synthase 1 (CTPS1) deamidates interferon (IFN) regulatory factor 3 (IRF3) to mute IFN induction. Our previous studies have implicated phosphoribosyl formylglycinamidine synthase (PFAS) and phosphoribosyl pyrophosphate amidotransferase (PPAT) in deamidating retinoic acid-inducible gene I (RIG-I) and evading dsRNA-induced innate immune defense in herpesvirus infection. Overall, these studies have uncovered an unconventional enzymatic activity of cellular GATs in metabolism and immune defense, offering a molecular link intimately coupling these fundamental biological processes. [ABSTRACT FROM AUTHOR]

Glycopolymers are functional polymers with saccharide moieties on their side chains and are attractive candidates for biomaterials. Postpolymerization modification can be employed for the synthesis of glycopolymers. Activated esters are useful in various fields, including polymer chemistry and biochemistry, because of their high reactivity and ease of reaction. In particular, the formation of amide bonds caused by the reaction of activated esters with amino groups is of high synthetic chemical value owing to its high selectivity. It has been employed in the synthesis of various functional polymers, including glycopolymers. This paper reviews the recent advances in polymers bearing activated esters for the synthesis of glycopolymers by postpolymerization modification. The development of polymers bearing hydrophobic and hydrophilic activated esters is described. Although water-soluble activated esters are generally unstable and hydrolyzed in water, novel polymer backbones bearing water-soluble activated esters are stable and useful for postpolymerization modification for synthesizing glycopolymers in water. Dual postpolymerization modification can be employed to modify polymer side chains using two different molecules. Thiolactone and glycine propargyl esters on the polymer backbone are described as activated esters for dual postpolymerization modification. [ABSTRACT FROM AUTHOR]

Pyridine‐borane complex was widely used as a reducing agent, but the exploration of such reagent as a catalyst for amidation of carboxylic acids are still unknown. Here we reported the first example of direct amidation of carboxylic acids catalyzed by pyridine‐borane complexes. This protocol features a low catalyst loading (0.2–10 mol %), broad substrate scope, good functional group compatibility, and affording the amides in high yields. [ABSTRACT FROM AUTHOR]

Furan heterocyclic compounds derived from renewable sources are popular versatile candidates for the production of multifunctional macromolecular materials. These compounds are also used as hydrophobilization monomers for reversible polyadducts or as versatile building blocks in Diels‐Alder reactions. In the present study, an efficient approach to chemoselective acylation of furfurylamine with a series of non‐preactivated monocarboxylic or dicarboxylic long‐chain fatty acids and some of their functionalized derivatives has been achieved via catalytic direct amidation in reversed micellar medium. A convenient and environmentally friendly method has been developed for furfurylamides via a dehydrative coupling reaction. For this purpose, a new cationic Brønsted‐type sulfonic acid catalyst containing a hexadecyl alkyl chain was synthesized and fully characterized. The present catalytic reaction produced the respective N‐furfurylamides materials in good to excellent yields. This study also confirms that the direct amidation of carboxylic acids with selected amine compounds can be successfully catalyzed by Brønsted acids. Its simplicity and high atom economy are the main advantages of this method. [ABSTRACT FROM AUTHOR]

The noticeable difference in the coefficient of thermal expansion (CTE) for polytetrafluoroethylene (PTFE) coatings and copper substrates is a major challenge for thermal debonding of the copper-clad laminate (CCL) in high-frequency communications. Theoretically, ceramic fillers with low CTEs in the coating can effectively reduce the gap, and there remains a trade-off between the dispersibility of fillers and the interfacial interactions with the polymeric matrix. Here, we propose a novel approach to prepare a pentafluorobenzoyl chloride (PFBC)-modified polydopamine (PDA) shell on silica particles by using amidation. Such modified particles perform excellent dispersion and exhibit diminished interfacial gaps in the PTFE matrix, which highly reduces CTE to 77 ppm/°C, accounting for only 48.1% of the neat coating. Moreover, the composite exhibits enhanced mechanical strength and toughness, and consequently suppresses thermal debonding in CCL under high-temperature conditions. Therefore, results present a promising potential for its use in the next-generation CCL of high-frequency communication devices. [ABSTRACT FROM AUTHOR]

Development of an environmentally friendly catalyst system is a highly attractive strategy for organic synthesis. In this work, a H-form mesoporous Beta (H-MBeta) zeolite with an irregular spherical particle shape was synthesized and was found to realize the direct amidation of styrene and nitriles for the synthesis of N-alkylated amides in the aqueous phase. This strong acidic H-MBeta catalyst exhibited superior activity and product selectivity compared with H-MBeta-0.3 and H-MBeta-1.0 zeolites obtained from the acid dealumination method. This was attributed to the presence of abundant strong Brønsted acid sites in the H-MBeta zeolite, which can induce the adsorption and activation of styrene through the C＝C bond interacting with protonic hydrogen, benefiting the formation of key intermediate carbocation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Wheat gluten (WG) containing gliadin and glutenin are considered the main allergens in wheat allergy as a result of their glutamine‐rich peptides. Deamidation is a viable and efficient approach for protein modifications converting glutamine into glutamic acid, which may have the potential for allergenicity reduction of WG. RESULTS: Deamidation by citric acid was performed to investigate the effects on structure, allergenicity and noodle textural properties of wheat gluten (WG). WG was heated at 100 °C in 1 m citric acid to yield deamidated WG with degrees of deamidation (DD) ranging from DWG‐25 (25% DD) to DWG‐70 (70% DD). Fourier‐transform infrared and intrinsic fluorescence spectroscopy results suggested the unfolding of WG structure during deamidation, and sodium dodecyl sulphate‐polyacrylamide gel electrophoresis showed molecular weight shifts at the 35–63 kDa region, suggesting that the deamidation mainly occurred on low molecular weight glutenin subunits and γ‐ gliadin of the WG. An enzyme‐linked immunosorbent assay of deamidated WG revealed a decrease in absorbance and immunoblotting indicated that the intensities of protein bands at 35–63 kDa decreased, which suggested that deamidation of WG might have caused a greater loss of epitopes than the generation of new epitopes caused by unfolding of WG, and thereby reduction of the immunodominant immunoglobulin E binding capacity, ultimately leading to the decrease in allergenicity. DWG‐25 was used in the preparation of recombinant hypoallergenic noodles, and the hardness, elasticity, chewiness and gumminess were improved significantly by the addition of azodicarbonamide. CONCLUSION: The present shows the potential for deamidation of the WG products used in novel hypoallergenic food development. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A simple protocol has been proposed for the visible light-induced aromatic amidation reaction to afford 3,4-dihydroquinolin-2(1H)-ones. The amidation proceeded smoothly without any photocatalyst at room temperature, and the desired products were obtained in 46–72% yields. [ABSTRACT FROM AUTHOR]

Summary: The Triticum monococcum cultivar Hammurabi has been considered a wheat with reduced gluten toxicity for intolerant people. To further reduce gluten toxicity, we tested two biotechnological treatments on Hammurabi flour, fermentation by endogenous microbiota and transamidation by microbial transglutaminase. After 1 day of fermentation, the detectable gluten content dropped to 51.4% ± 6.4% (R5‐ELISA). Interestingly, microbial hydrolysis did not change the content of the water‐insoluble gliadin fraction. Transamidation of Hammurabi caused a greater reduction of the native gluten to 33.5% ± 3.3% (P < 0.01) and changed its physical properties, as it became water soluble. Interestingly, only dough from transamidated Hammurabi flour could leaven, similarly to the untreated dough, while in fermented Hammurabi dough, the rising activity of the added yeast was inhibited. Baking analysis indicated no substantial difference between transamidated and untreated Hammurabi breads. Descriptive sensory analysis showed that darkness appearance parameters and texture parameters were significantly altered in transamidated bread. Importantly, the treatment did not influence wheaty flavour or cereal odour, two mainly expected organoleptic features. Our data may have important implications in the perspective of manufacturing innovative foods for people predisposed to or suffering from gluten intolerance. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Palladium‐catalyzed regioselective amination of unactivated alkene remains a challenge and is of great interest. Herein, a three‐component coupling of unactivated alkene, sulfonamide, and N‐halo compounds accessing vicinal haloamine has been conceived. This aminohalogenation represents a modular and regioselective strategy. The electrophilic halogenating agent enables regioselective anti‐Markovnikov aminopalladation and facilitates subsequent halogenation events. And this protocol is characterized by gram‐scale syntheses and late‐stage functionalizations. Of note, the recovered byproduct phthalimide allows for reusing by conversion to the starting material. [ABSTRACT FROM AUTHOR]

Mycobacterium marinum CAR (Mm CAR) is one of the most widely used CARs as the key enzyme for the synthesis of aldehydes, alcohols and further products from the respective carboxylic acids. Herein, we describe the first functionally secreted 131 kDa CAR and its isolated A-domain using Komagataella phaffii and a methanol-free constitutive expression strategy. Precipitated and lyophilized Mm CAR (500 µg) was isolated from the culture supernatant and showed no decrease in activity for piperonylic acid (80% conversion), even when stored for up to 3 weeks at 4°C. Lyophilized Mm CAR precipitate gave 48% yield of E/Z -nonanal-4-nitrobenzoyloxime from the reduction of nonanoic acid and in-situ derivatization with O -4-nitrobenzoyl-hydroxylamine. Furthermore, K. phaffii could successfully secrete the Mm CAR adenylation domain. Its activity was confirmed by the amidation of benzoic acid with n -hexylamine. Neither enzyme variant was glycosylated by the yeast. In summary, functional CAR can be secreted by K. phaffii and used for cell free conversion of carboxylic acids to various products. [Display omitted] • Active full-length Mm CAR and Mm CAR A-domain were secreted by Komagataella phaffii for the first time. • Mm CAR A-domain was active for amidation of benzoic acid with n-hexylamine. • Precipitated, lyophilized full-length Mm CAR can be stored without activity loss at 4°C for at least 3 weeks. [ABSTRACT FROM AUTHOR]

The transition metal‐catalysed C−H bond functionalization has emerged as a powerful tool for accessing numerous organic compounds in greener manner with step and atom economy. Remarkable progress has been made in the metal‐catalysed C−H bond functionalization during the past decades and the trend is continuing as new reactions are being added. In the transition metal‐catalysed C−H bond functionalization, a growing attention has been paid on ruthenium, particularly, the stable ruthenium(II) as it allows several C−H bond functionalization reactions to perform in water with high selectivity. The ruthenium‐catalysed C−H bond functionalization reactions, such as arylation, alkenylation, annulation, cyanation, amination and silylation just to mention some have been well documented in numerous published papers, book chapters and review articles. However, as ruthenium‐catalysed C−H functionalization has been growing rapidly, a comprehensive review is necessary from time to time to highlight the progress made in this ever expanding field. In view of this, the manuscript presents the ruthenium‐catalysed direct C−O, C−N and C‐halogen bond forming reactions involving aromatic C−H bond covering oxygenation, amination, amidation, imidation, nitration and halogenation reported from 2012 to 2022. [ABSTRACT FROM AUTHOR]

The present study demonstrates the influence of small portion (20 %) of organic co‐solvent (DMSO/THF/ACN/MeOH) in mixed aqueous media (80 % water) in controlling the size, quantum yield and life time of the through space charge transfer assemblies (TSCT) of pentacenequinone derivative (TPy‐PCQ‐TPy). Among various solvent systems [H2O : DMSO (8 : 2), H2O : THF (8 : 2), H2O : ACN (8 : 2) and H2O : MeOH (8 : 2)] examined, highly emissive (Φf=12 %) and nano‐sized assemblies having long life time (3.11 ns) were formed in H2O : DMSO (8 : 2) solvent system. The solvent dependent differences in the size and excited state properties of TPy‐PCQ‐TPy assemblies are reflected in their photosensitizing behaviour in different solvent systems. Backed by excellent photosensitizing properties, TPy‐PCQ‐TPy assemblies smoothly catalyse the photoamidation reactions between unactivated/activated aldehydes and secondary amine under mild reaction conditions (visible light irradiation, aerial atmosphere, room temperature) in H2O : DMSO (8 : 2) solvent mixture. The as prepared assemblies of TPy‐PCQ‐TPy also exhibit high potential to catalyse the oxidation of benzyl alcohols to aromatic aldehydes, thus, generating a possibility to use aromatic alcohols as the starting material in photoamidation reactions. The real time application of TSCT assemblies has also been demonstrated in gram scale transformation of aromatic aldehydes to aromatic amides and photooxidation of benzyl alcohol to aromatic aldehyde. [ABSTRACT FROM AUTHOR]

Cilia are microtubule-based cellular projections that act as motile, sensory, and secretory organelles. These structures receive information from the environment and transmit downstream signals to the cell body. Cilia also release vesicular ectosomes that bud from the ciliary membrane and carry an array of bioactive enzymes and peptide products. Peptidergic signals represent an ancient mode of intercellular communication, and in metazoans are involved in the maintenance of cellular homeostasis and various other physiological processes and responses. Numerous peptide receptors, subtilisin-like proteases, the peptide-amidating enzyme, and bioactive amidated peptide products have been localized to these organelles. In this review, we detail how cilia serve as specialized signaling organelles and act as a platform for the regulated processing and secretion of peptidergic signals. We especially focus on the processing and trafficking pathways by which a peptide precursor from the green alga Chlamydomonas reinhardtii is converted into an amidated bioactive product—a chemotactic modulator—and released from cilia in ectosomes. Biochemical dissection of this complex ciliary secretory pathway provides a paradigm for understanding cilia-based peptidergic signaling in mammals and other eukaryotes. [ABSTRACT FROM AUTHOR]

An environmentally benign, transition metal- and base-free, iodine-promoted atom-economical protocol for the synthesis of the privileged isoquinolone scaffold via regioselective intramolecular iodoamidation of alkynes under mild conditions has been developed. The present synthetic approach being metal, additive, and solvent-free adheres to the principles of green chemistry, as it tends to minimize waste production. The synthesized product contains an iodo as well as a free –OH group that is readily accessible for subsequent transformation to afford biologically relevant compounds. [ABSTRACT FROM AUTHOR]

The production of catalytic materials from large-scale wastes represents an interesting way of sustainability which is largely untapped resource. The 'waste into treasure' turning strategy provides a possible way for synthesis of nanomaterial, having diverse environmental and industrial applications, in an eco-friendly way. Egg shell is abundantly available, cost-effective and renewable, possessing unique hierarchically porous structure which has been widely investigated in the field of adsorption, energy as well as catalysis. Herein, we are reporting a rationally fabricated LaCoO3 supported egg shell (LaCoO3/ES, LCES) using waste egg shell as template. The synthesized material was characterized using different techniques and used as nanocatalyst. The LaCoO3/ES catalyzed the reduction of 4-nitophenol (4-NP) to less toxic 4-aminophenol (4-AP) and methyl orange into its reduced less hazardous and decolorized product with high efficiency. Amides were also synthesized using base and solvent-free conditions via grinding showing increased catalytic performance. Therefore, the results obtained support a synergistic effect between cobalt and lanthanum ions that enhanced the catalytic activity for both reduction and amidation of esters. In the amidation series, a new product, namely N1, N3-bis(4-methylbenzyl) malonamide, was also synthesized. In addition, we were also able to successfully grow a single crystal of one of the compounds such as N-benzyl-2-cyanoacetamide and confirmed by Single Crystal X-ray Crystallography. [ABSTRACT FROM AUTHOR]

The conjugation of biomolecules to quantum dots has recently gained attention in the field of bionanotechnology. Graphene quantum dots (GQDs) have been employed in various sensing applications due to their tunable fluorescence, controllable size, low cytotoxicity, and high biocompatibility. In this work, sulfur-doped graphene quantum dots (S-GQDs) were conjugated to glucose oxidase (GOx) for the potential detection of glucose. Fluorescent S-GQDs were synthesized via one-step pyrolysis of citric acid and thioglycolic acid at 200 °C. S-GQDs were conjugated to GOx using the carbodiimide/succinimide (EDC/NHS) coupling reaction, followed by purification via centrifugal ultrafiltration. Fluorescence spectroscopy, UV-Vis absorption spectroscopy, and transmission electron microscopy were employed to characterize the S-GQDs and S-GQD-GOx conjugates. The S-GQDs obtained had an average diameter of 49.8 ± 7.4 nm (n = 12) and emitted strong blue fluorescence (λem = 460 nm) when excited with 365-nm UV light. Trinder's assay was used to assess the catalytic activity of free GOx and the S-GQD-GOx conjugates. The S-GQD-GOx conjugates consistently showed significantly greater catalytic activity compared to free GOx. The results obtained open avenues for the fabrication of a sensitive fluorescent GQD-based glucose probe in the future. [ABSTRACT FROM AUTHOR]

We developed intramolecular carboxyamidations of alkyne‐tethered O‐acylhydroxamates followed by either thermally induced spontaneous or 4‐(dimethylamino)pyridine‐catalyzed O→O or O→N acyl group migration. Under iron‐catalyzed conditions, the carboxyamidation products were generated in high yield from both Z‐alkene and arene‐tethered substrates. DFT calculations indicate that the iron‐catalyzed carboxyamidation proceeds via a stepwise mechanism involving iron‐imidyl radical cyclization followed by intramolecular acyloxy transfer from the iron center to the alkenyl radical center to furnish the cis‐carboxyamidation product. Upon treatment with 4‐(dimethylamino)pyridine, the Z‐alkene‐tethered carboxyamidation products underwent selective O→O acyl migration to generate 2‐acyloxy‐5‐acyl pyrroles. Thermal O→N acyl migration occurs during carboxyamidation if the Z‐alkene linker contains an alkyl or an aryl substituent at the β‐position of the carbonyl group. On the other hand, the arene linker‐containing compounds selectively undergo O→N acyl migration to generate N‐acyl‐3‐acylisoindolinones, and the corresponding O→O acyl migration forming isoindole derivatives was not observed. [ABSTRACT FROM AUTHOR]

This article discusses two separate studies on the diastereoselective cross-dehydrogenative coupling reactions of amides with diarylmethanes. The first study focuses on the use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as an oxidant, while the second study explores the use of a chiral-auxiliary technique. Both studies demonstrate the successful synthesis of various products with high yields and diastereoselectivities. The findings provide valuable insights into the development of efficient approaches for these reactions, and further research is being conducted to explore the scope of other nucleophiles in this reaction. [Extracted from the article]

This article discusses the synthesis of ynamides, a class of N-alkynyl compounds, through various catalytic reactions. The authors highlight the importance of ynamides in the synthesis of nitrogen-containing scaffolds and summarize existing methods for their synthesis. They also present their own research on the direct catalytic addition of terminal alkynes to azodicarboxylates to produce ynehydrazides, which can then be converted into ynamides. The authors propose potential future directions for further research in this field. [Extracted from the article]

Efficient NNN‐pincer type bis(imino)pyridine ligand based zinc(II) catalyzed intermolecular amidation of benzylic hydrocarbons with sulfonamides has been developed. The zinc complexes were synthesized by the reaction of bis(imino)pyridine ligand with zinc(II) precursors such as Zn(OAc)2 ⋅ 2H2Oand ZnBr2. The structure of the bis(imino)pyridine‐Zn(OAc)2 complex was characterized by single crystal X‐ray diffraction. The zinc(II)‐bis(imino)pyridine complexes were utilized as catalysts for the intermolecular amidation of benzylic C(sp3)−H bond in the presence of N‐bromosuccinimide (NBS) as an oxidant. A broad range of substrates delivered the products in moderate to good yields. This protocol provides the synthesis of various amides viaC−H activation. [ABSTRACT FROM AUTHOR]

An efficient strategy towards stereoselective amidation of alkynes is reported. The given method features operational simplicity, excellent functional group tolerance, broad substrate scope and fast kinetics to furnish Z-enamides. Moreover, the method was successfully applied for the facile synthesis of the natural products lansiumamide A, lansiumamide B and Z-alatamide. Notably, DMSO plays two vital roles: hydrogen source and solvent. [ABSTRACT FROM AUTHOR]

Borane-pyridine acts as an efficient (5 mol%) liquid catalyst, providing improved solubility for the direct amidation of a wide range of aromatic and aliphatic carboxylic acids and amines to form secondary and tertiary carboxamides. Tolerance of potentially incompatible halo, nitro, and alkene functionalities has been demonstrated. [ABSTRACT FROM AUTHOR]

A rhodium-catalyzed C–H selective amination of 2,4-diarylquinazolines has been developed with the commercially available N -fluorobenzenesulfonimide as the amino source. This approach offers a unique route for direct C–H amidation and demonstrates remarkable functional group tolerance and regioselectivity. [ABSTRACT FROM AUTHOR]

Oxindoles are prevalent structures in natural products and pharmaceutically active molecules. To support structure–activity‐relationship (SAR) studies in a medicinal chemistry program, we developed a straightforward and scalable synthesis route to 1‐aminoethyl oxindole building blocks harboring various types of substituents. Our strategy relies on an intramolecular Buchwald–Hartwig amidation of a 2‐bromophenylacetic amide precursor. The cyclization substrates can be prepared from readily available benzaldehydes by ortho‐selective C(sp2)−H bromination followed by homologation to the corresponding phenylacetic acid derivatives. The process was optimized to allow for preparation of 246 g of one representative example. [ABSTRACT FROM AUTHOR]

Transamidation of acetamide with primary methylamine and benzylamine for secondary amide formation has been examined at the M06‐2X(SMD)/6‐311++G(2df,2p)//M06‐2X(SMD)/6‐31+G(d) level. Two alternative mechanisms are taken into account involving non‐covalent catalysis by hydrogen‐bonding (Path I) and covalent catalysis via hydroxamic acid formation (Path II). In Path I, hydroxylamine hydrochloride activates acetamide through hydrogen bonding in favor of nucleophilic attack of methylamine/benzylamine, while in Path II the initial nucleophilic attack of hydroxylamine generates the intermediate hydroxamic acid for subsequent aminolysis. In Path I and Path II, N‐path and O‐path are considered, where proton shifts to NH2 or via carbonyl oxygen with OH group generated for leaving NH3, respectively. Our computational results manifest that Path II via O‐path is more favorable with lower free energy barriers of 21.9 (ammonia‐mediated), 22.7 (methylamine‐mediated) and 23.0 kcal mol−1 (hydroxylamine‐mediated) than Path I for methylamine as nucleophile. The ammonia‐mediated Path II via O‐path for benzylamine as nucleophile is still the most favorable pathway, with a free energy barrier of 22.1 kcal mol−1. The preference of Path II over Path I is rationalized by NBO analysis. Our theoretical results give useful insight to design more effective catalysts for activating the carboxamide in the future. [ABSTRACT FROM AUTHOR]

Amide bond construction has garnered significant interest in recent decades due to amides being one of the most prevalent functional groups among bioactive molecules. Out of the thirty‐seven new drugs approved by the FDA in 2022, eleven are small molecules containing at least one amide bond. Additionally, there are nineteen large molecules approved as new drugs, some of which have peptide structures, and therefore, also bear amide bonds. In recent years, multiple teams have embraced the challenge of developing more efficient methods for amide bond formation. This dedication has led to numerous publications appearing monthly in prestigious journals, showcasing significant advancements in this field. The primary goal of this review is to present the most viable strategies for constructing the amide bond. It is crucial to differentiate between amide bond formation and amide synthesis; hence, the focus is on describing specific methods for forming new C(O)−N bonds. In particular, this review concentrates on the methods developed within the last six years. There is a particular emphasis on new approaches that consider the thought process when selecting the starting materials and functional groups. This approach ensures coverage of all the most common chemical transformations that yield new amide bonds. [ABSTRACT FROM AUTHOR]

Herein we disclose a palladium‐catalyzed procedure for the transamidation of structurally diverse amides with amines based on the use of molecular oxygen as palladium‐activating agent. The reaction, which is scalable and amenable for the preparation of enantioenriched compounds, is carried out in a bio‐degradable solvent often used as a fuel additive, diethyl carbonate. As a result of the 10−4 mol% of catalyst required, final products are isolated containing palladium impurities in a concentration of 0.1 ppm. Two kinetically different mechanistic pathways are proposed for this reaction on account of a number of experiments such as kinetic curves, TEM images, catalyst poisoning experiments, UPLC‐ESI‐MS identification of intermediates and EPR spectra of reaction crude. [ABSTRACT FROM AUTHOR]

Three‐component tandem Ritter and Mannich reactions were developed for one‐pot arylation and acyl protected amination of isatin. The acid catalyzed reaction produced wide variety of 3‐aryl‐3‐amidooxindoles directly from commercially available isatin. The C3 functionalization of isatin is affected by condensation with electron rich arenes and nitriles or amides with concomitant C−C and C−N bonds formation. Substituted isatins, different nucleophiles (cyclic and acyclic N, N‐disubstituted arylamines), aliphatic nitriles, and amides expanded the scope of the reaction. The reaction is simple, general, efficient and can switch the amidation substrate from nitriles in Ritter reaction to amides in Mannich reaction. [ABSTRACT FROM AUTHOR]

The endo- and exo-N-heterocyclic carbene precursors based on camphor were prepared diastereoselectively in five synthetic steps starting from (1S)-(+)-ketopinic acid. The obtained N-heterocyclic carbene precursors were investigated in an asymmetric benzoin reaction. All new compounds were fully characterized, and the absolute configurations were determined via X-ray diffraction and NOESY measurements. [ABSTRACT FROM AUTHOR]

The formation of amide bonds is an important process since this linkage is an essential component in proteins, pharmaceuticals, and other medicinally and biologically significant molecules. Recently, it was demonstrated that germylamines R3GeNR'2 were useful reagents for the conversion of acid fluorides to amides. This transformation occurs readily at room temperature and has a low activation energy. In the present study, the versatility of this amidation reaction with aryl acid fluorides is investigated. A series of thirteen acid fluorides with various substituents on the aromatic ring were reacted with the germylamine Ph3GeNMe2 and twelve of these were converted to the corresponding amides in high yields, the exception being 1,4‐benzenedicarbonyl difluoride. The germylamines Bun3GeNMe2 and Pri3GeNMe2 also could be used for this interconversion, and both of these species successfully converted 1,4‐benzenedicarbonyl difluoride to the corresponding amide. In addition, the crystal structure of Ph3GeNMe2 is reported. This represents one of only three crystallographically characterized germylamines. The synthesis and 19F NMR characterization of three fluorogermanes R3GeF (R=Bun, Pri, and Mes) are also reported herein. [ABSTRACT FROM AUTHOR]

Asparagine deamidation is a post-translational modification (PTM) that converts asparagine residues into iso-aspartate and/or aspartate. Non-enzymatic asparagine deamidation is observed frequently during the manufacturing, processing, and/or storage of biotherapeutic proteins. Depending on the site of deamidation, this PTM can significantly impact the therapeutic's potency, stability, and/or immunogenicity. Thus, deamidation is routinely monitored as a potential critical quality attribute. The initial evaluation of an asparagine's potential to deamidate begins with identifying sequence liabilities, in which the n + 1 amino acid is of particular interest. NW is one motif that occurs frequently within the complementarity-determining region (CDR) of therapeutic antibodies, but according to the published literature, has a very low risk of deamidating. Here we report an unusual case of this NW motif readily deamidating within the CDR of an antibody drug conjugate (ADC), which greatly impacts the ADC's biological activities. Furthermore, this NW motif solely deamidates into iso-aspartate, rather than the typical mixture of iso-aspartate and aspartate. Interestingly, biological activities are more severely impacted by the conversion of asparagine into iso-aspartate via deamidation than by conversion into aspartate via mutagenesis. Here, we detail the discovery of this unusual NW deamidation occurrence, characterize its impact on biological activities, and utilize structural data and modeling to explain why conversion to iso-aspartate is favored and impacts biological activities more severely. [ABSTRACT FROM AUTHOR]

Deamidation, a common post-translational modification, may impact multiple physiochemical properties of a therapeutic protein. MEDI7247, a pyrrolobenzodiazepine (PBD) antibody–drug conjugate (ADC), contains a unique deamidation site, N102, located within the complementarity-determining region (CDR), impacting the affinity of MEDI7247 to its target. Therefore, it was necessary to monitor MEDI7247 deamidation status in vivo. Due to the low dose, a sensitive absolute quantification method using immunocapture coupled with liquid chromatography–tandem mass spectrometry (LBA-LC-MS/MS) was developed and qualified. We characterized the isomerization via Electron-Activated Dissociation (EAD), revealing that deamidation resulted in iso-aspartic acid. The absolute quantification of deamidation requires careful assay optimization in order not to perturb the balance of the deamidated and nondeamidated forms. Moreover, the selection of capture reagents essential for the correct quantitative assessment of deamidation was evaluated. The final assay was qualified with 50 ng/mL LLOQ for ADC for total and nondeamidated antibody quantification, with qualitative monitoring of the deamidated antibody. The impact of deamidation on the pharmacokinetic characteristics of MEDI7247 from clinical trial NCT03106428 was analyzed, revealing a gradual reduction in the nondeamidated form of MEDI7247 in vivo. Careful quantitative biotransformation analyses of complex biotherapeutic conjugates help us understand changes in product PTMs after administration, thus providing a more complete view of in vivo pharmacology. [ABSTRACT FROM AUTHOR]

A one-pot synthesis approach to access sulfonamide-containing derivatives of dibenzo[1,4]thiazepine using primary amines and 2-[(2-nitro-4-sulfamoylphenyl)sulfanyl]benzoic acid as precursors was developed. The approach is based on a sequence of amidation steps and the subsequent tandem of the Smiles rearrangement and denitrocyclization reaction. The resulting tricyclic systems showed pronounced activity as inhibitors of bovine carbonic anhydrase isoform II. [ABSTRACT FROM AUTHOR]

Synthetic methodologies based on cycle expansion reactions have proven to be highly effective in delivering valuable medium‐sized cycles and macrocycles. A primary method of ring expansion relies on intramolecular transamidation reactions. These reactions typically employ N‐aminoalkyl and N‐aminoacyl derivatives of lactams and their analogues as starting materials, yielding a diverse spectrum of unique nitrogen‐containing heterocycles. This Review aims to provide a comprehensive analysis of the research outcomes related to intramolecular transamidation reactions that lead to cycle expansion. This will offer the reader a perspective on the potential applications of such reactions in generating novel and intriguing types of heterocyclic systems. [ABSTRACT FROM AUTHOR]

We present a solvent-free thermo-mechanochemical approach for the direct coupling of carboxylic acids and amines, which avoids activators and additives. Detailed analysis of the reactions by ex situ and in situ monitoring methods led to the observation, isolation, and characterisation of multicomponent crystalline intermediates that precede the formation of amides. We applied our methodology for the quantitative synthesis of the active pharmaceutical ingredient moclobemide. [ABSTRACT FROM AUTHOR]

An efficient ex‐situ method for the amidation of carboxylic acids mediated by CDI has been disclosed herewith. This metal‐free strategy is performed at ambient temperature and can be applied effectively for late‐stage modification of amino acids and APIs. [ABSTRACT FROM AUTHOR]

The synthesis of N‐pyridinylamides has been realized by particularly efficient technologies via bimetallic organic (Co/Fe‐MOF) catalyzed oxidative amidation between 2‐aminopyridine and benzaldehyde. The C−N bond was formed with the presence of a catalyst (Co/Fe‐MOF) as a Lewis acid and the oxidant as DTBP. The oxidative amidation reaction was conducted in 1,4‐dioxane at 120 °C with a wide range of substrates producing the corresponding amide products in good to 94 % yields. Experimental results illustrated that This accessibly offers a significant improvement over the earlier successful attempts in forming N‐pyridinyl amides. The Co/Fe‐MOF material was synthesized by solvothermal methods with the salt mixture of Fe(NO3)3.9H2O and Co(NO3)2.6H2O. The material was determined by modern analytic methods like X‐ray diffraction (XRD), Fourier‐transform Infrared spectroscopy (FT‐IR), Scanning Electron Microscope (SEM), and N2 adsorption/desorption isotherms. [ABSTRACT FROM AUTHOR]