Search

Comprehensive Summary: Indolizine is a nitrogen‐containing heterocycle with strong aromaticity, possessing a delocalized 10π‐electron system. Based on the indolizine scaffolds, numerous molecules with biological activity and organic functional materials have been synthesized. Since 2016, over 110 papers have been published on the synthesis of indolizine scaffolds, but the reviews on synthesizing indolizine scaffolds have been incomplete and not up‐to‐date. Herein, from the perspective of the structure of indolizine with the combination of pyrrole and pyridine ring, we focus on the construction of indolizine scaffolds through the diversity of starting substrates, including pyridine derivatives (N1‐substituted pyridinium salt derivatives, C2‐substituted pyridine derivatives, N1‐ and C2‐free substituted pyridine derivatives), pyrrole derivatives and unoriginal ring substrates. Furthermore, the corresponding reaction mechanisms of synthetic methodologies are also elaborated. Therefore, this review not only paves the way for indolizine synthesis but also provides insight into exploring new reaction modes for constructing nitrogen‐containing heterocycles. Key Scientists: Indolizine was discovered by Angeli in 1890 and first prepared by Scholtz in 1912 from α‐picoline and acetic anhydride. A general approach was developed by Chichibabin in 1927, that is of practical value for the preparation of 2‐alkyl‐ or 2‐arylindolizines. The Chichibabin reaction was the ring closure of quaternary pyridinium halides. At the begining of the 21st century, Basavaiah introduced a new dimension in the Baylis‐Hillman chemistry leading to a novel facile convenient methodology for synthesis of indolizine scaffolds in one‐pot operation. In 2010, Barluenga reported Cu(I)‐catalyzed regioselective [3+2] cyclization of unsubstituted pyridines toward alkenyldiazoacetates leading to functionalized indolizine derivatives, that was the first successful example of metal‐catalyzed cyclization of a π‐deficient heterocyclic system with alkenyldiazo compounds. In 2019 and 2022, Xi and Liu exploited the methods of non‐pyridine derivatives as starting materials to synthesize indolizines, respectively. In 2022, Guo developed an environmentally benign electrooxidative approach for constructing formyl‐ and acyl‐substituted indolizines. [ABSTRACT FROM AUTHOR]

AbstractVitamin E is an important fat soluble antioxidant, its acetate is the main derivative product of vitamin E. Using metal organic framework material ZIF-8 as a catalyst, vitamin E acetate (VEA) was prepared by catalyzing the esterification reaction of D-α-tocopherol and acetic anhydride in a solvent-free system. Firstly, the preparation conditions of metal organic framework materials were studied: different imidazole ligands, different zinc ion ligands, molar concentration ratio of Zn2+ to 2-methylimidazole(2-mIM), and preparation time. The results showed that the catalytic performance of ZIF-8 was optimal when Zn(CH3COO)2·2H2O was used as the zinc source, 2-mIM was used as the imidazole ligand, the molar concentration ratio of Zn2+ / 2-mIM was 1:20, and the preparation time was 1 hour. The yield of vitamin E acetate was 86.85%. The synthesis process of VEA was optimized by single factor experiments such as substrate molar ratio, reaction time, dosage of nano enzyme, reaction temperature and so on. The results showed that the yield of vitamin E acetate reached 96.31% under the optimal conditions of n (D-α-tocopherol) =1mmol, [n (D-α-tocopherol) : n (Acetic anhydride)] =1:15, reaction time 24 h, ZIF-8 dosage 0.05 g, reaction temperature 50 °C. [ABSTRACT FROM AUTHOR]

With the advancement of lightweight and high-strength fiber-reinforced composites, various chemical modification methods have been proposed to improve the compatibility between fiber and plastic matrix. Among these, acetic anhydride modification is particularly notable, but its low activity necessitates the use of hazardous agents and results in suboptimal mechanical properties after reinforcement. Herein, a solvent-free and recoverable esterification approach was developed to modify pulp fibers with propionic anhydride (PAF). Subsequently, the high-density polyethylene (HDPE) was reinforced at multiple levels through capacity addition, filling, and premixing. The results showed that the optimal mechanical properties and minimum coefficient of thermal expansion (CTE) of HDPE/PAF composites were achieved at a DS value of 0.40. Compared to the unmodified fiber-reinforced composites, propionylation not only improved the discoloration of HDPE/PAF composites but also enhanced its hydrophobicity, as evidenced by an increase in the water contact angle from 89.2° to 103.4°. Moreover, compared to the neat HDPE, the tensile strength and modulus increased by a factor of 2.4 and 3.3, respectively, surpassing the improvements reported for other acid anhydride modifications. These findings indicated that the PAF could be uniformly dispersed in the HDPE matrix through a dual network structure. The successful attempts to reinforce other polyolefin matrices and achieve kilogram-scale production have demonstrated the practicality and feasibility of this approach for industrial applications. [ABSTRACT FROM AUTHOR]

A novel strategy has been developed for the direct and regioselective ortho -acetoxylation of N -(2-benzoylphenyl)benzamides through C–H activation using a catalytic amount of Pd(OAc)2 (5 mol%) and a stoichiometric amount of PhI(OAc)2 in a mixture of acetic anhydride and acetic acid. By using this protocol, a new series of niclosamide derivatives was produced in good yields. This is the first report on the synthesis of niclosamide and its derivatives by means of C–H functionalization. This newly developed method offers several advantages such as high regioselectivity, operational simplicity, and good to excellent yields. It provides a short three-step process for the synthesis of niclosamide involving acid–amine coupling, ortho -acetoxylation through C–H activation, and deacylation. [ABSTRACT FROM AUTHOR]

The high value‐added utilization of the fluorinated silica slag (FSS) waste, an associated by‐product of the anhydrous HF production from the accompanying fluorine resources in phosphate ore, is of great importance, but it remains a challenge. In this work, the Mg modified and unmodified Hβ zeolites from FSS waste were successfully prepared by a green dry gel conversion crystallization method with tetraethylammonium hydroxide (TEAOH) as a structure‐directing agent (SDA). The in situ Mg modified Hβ zeolite (Mg−Hβ) shows much superior catalytic performance to unmodified (Hβ) and post Mg‐modified Hβ (Mg/Hβ) zeolites for acetylation of 2‐methoxynaphthalene (2‐MN) to 6‐acetyl‐2‐methoxynaphthalene (2,6‐AcMN), and the 40.2 % of conversion for 2‐MN with 66.3 % of selectivity for 2,6‐AcMN were achieved, ascribed to the high amount of B acidic sites and the promoted shape‐selective catalysis effect by higher surface area and volume of micropores. This work not only opens a new avenue for the high value‐added utilization of fluorinated silica slag waste, but also generates an efficient solid acid catalyst for the clean production of 2,6‐AcMN through the acetylation of 2‐MN with acetic anhydride. [ABSTRACT FROM AUTHOR]

A regioselective novel one-pot synthesis of heterocyclic purine derivative antiviral agent Ganciclovir in which initially guanine is treated with acetic anhydride in the presence of iodine (5%) to get diacetyl guanine intermediate, which undergoes in situ N-alkylation with AMDP in presence of catalytic acidic Amberlite IR-120 to get N-alkylated intermediate and finally deacetylation to get pure regioselective Ganciclovir, which is commercially viable and eco-friendly. We developed one-pot synthesis of antiviral drug Ganciclovir. Initially, Guanine is treated with acetic anhydride and iodine to yield diacetyl guanine 3. This intermediate then reacted with AMDP in the presence of acidic Amberlite IR-120 to obtain compound 5. Finally, deacetylation yields Ganciclovir 1, a commercially viable and eco-friendly process. [ABSTRACT FROM AUTHOR]

The gel skeletal reinforcement (GSR) method was applied at the preparation stage of β‐zeolite to prepare a novel hierarchical catalyst. A solution of hexamethyldisiloxane (HMDS) and acetic anhydride, a GSR reagent, was added to the mixture of colloidal silica, sodium aluminate, tetraethylammonium hydroxide, sodium hydroxide and water, and successive aging and hydrothermal treatment gave microporous β‐zeolite surrounded by mesoporous silica like core‐shell structure. Its properties were characterized by XRD, nitrogen adsorption and desorption, NH3‐TPD, TEM, and TG‐DTA measurements, and further characteristics of the catalysts produced were clarified by the catalytic cracking of n‐dodecane. The hierarchical structure of microporous zeolite and mesoporous silica was shown from GSR‐2.9HS−H‐Beta to GSR‐3.2HS−H‐Beta, where the molar ratio of HMDS and silica source of β‐zeolite was 2.9~3.2 : 100. It was found that in the catalytic cracking of n‐dodecane, the relative activity (the conversion per the amount of zeolite crystals) increased with the increase in mesopore volume and surface area. The result indicated that the introduction of mesopores was effective even in catalytic cracking of small molecule of n‐dodecane. [ABSTRACT FROM AUTHOR]

Carbyne free radicals (RC) are usually associated with high‐energy processes, thus research on their preparation, chemical reactivity, and prevalence under mild conditions is scarce. Recently, it was reported that metallo‐complexes containing CR ligands may undergo spontaneous degradation in aqueous solutions to produce free RC radicals. These highly reactive species may react with each other to form the corresponding alkyne and other products. The reaction of 1,1,1 halo‐carbo‐hydrates with Cr(II) ions also forms RC radicals under mild conditions. Herein, we report two additional synthetic routes that produce free RC radicals under mild conditions. First, the reaction between metallic zinc and acetic anhydride produces 2‐butyne and several other C2, C3, and C4 compounds. Isotopic‐labeling experiments indicate that the formation of 2‐butyne results from an inter‐molecular reaction in which two RC moieties from two acetic anhydride molecules combine in solution. In addition, the degradation of the tri‐molybdenum complex [Mo3(H3CC≡CCH3)(OAc)(H2O)2Br7], in which a 2‐butyne ligand is coordinated to the Mo3 framework in a μ3‐η2 (⊥) binding mode in aqueous solution produces several C2, C3, C4 and C5 molecules. This indicates the formation of free CH3C radicals by a homolytic cleavage of the carbon‐carbon triple bond. [ABSTRACT FROM AUTHOR]

A series of benzoquinoline-based heterocycles was synthesized using 2-((3-chlorobenzo[f]quinolin-2-yl)methylene)hydrazine-1-carbothioamide as a key material via condensation of 3-chlorobenzo[f]quinoline-2-carbaldehyde with thiosemicarbazide. The titled thiosemicarbazone scaffold was conducted with some carbon electrophilic reagents such as acetic anhydride, chloroacetyl chloride, chloroacetic acid, 2-bromo-1-(3-nitrophenyl)ethan-1-one, 2-chloro-N-phenylacetamide, and dimethyl but-2-ynedioate to obtain triazole thione, imidazolone, thiazolidinone, and thiazole derivatives. On the other hand, hydrazinolysis of thiosemicarbazone did not proceed as expected but it gave the azine derivative. The in vitro antitumor and antioxidant activity of the synthesized compounds were screened and revealed that triazole thione and thiazole derivatives were the most potent. [ABSTRACT FROM AUTHOR]

Acetic acid‐mediated three‐component double Friedel–Crafts alkylation reaction for the synthesis of α, α‐diaryl oxindole derivatives is demonstrated. The reaction is successful with various isatin, indole, and N, N‐disubstituted aniline derivatives. The efficiency of the reaction is further enhanced by a four‐component reaction of isatin, electrophiles and acetic anhydride for the synthesis of N‐acylated 3,3‐diaryl oxindole derivatives facilitated by dual activation of C3 and N1 acetylation in a single‐step. Various unsymmetrical and symmetrical 3,3‐diaryl oxindoles were prepared in single‐step MCR reaction under easy to operate reaction conditions. [ABSTRACT FROM AUTHOR]

L‐lactide (LA) is polymerized with ethyl L‐lactate or trifluoroethanol as initiators (LA/In = 30/1), and the resulting poly(L‐lactide) esters are acetylated with acetic anhydride. The acetylated PLA esters are mixed with SnOct2, dibutyltin bis(4‐chlorophenoxide), or dibutyltin bis(pentafluorophenoxide) in solution and crystallized at 120 °C. The doped crystals are annealed at 140 °C or at 160 °C for 7, 14, and 28 days, and the chemical modifications that occurred in the solid state are monitored by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) measurements. All catalysts promoted polycondensation, while no significant formation of cycles is observed. However, in the presence of SnOct2, disproportionation of chains occurred upon annealing at 120 or 140 °C, and crystallites consisting of extended chains with Mn values ≈3500 – 3600 and low dispersities (Ð < 1.5) are formed. [ABSTRACT FROM AUTHOR]

A mild strategy was developed for efficient preparation of acetylsalicylic acid (ASA) from the acetylation of salicylic acid (SA) and acetic anhydride (AA) assisted ultrasonic over Y-immobilized cation exchange resin (Y-CER). With this strategy, an ASA yield of 95.2% was obtained. The results showed that the increased yield was due to Lewis acidic sites (LAS) combined with ultrasonic assistance. The process reduced the AA reagent feed while lowering the reaction temperature. The characterization results showed that metal Y species were dispersedly anchored on the CER surface through S-O-Y triple-dentate bonds, resulting in abundant LAS and stable catalytic activity. Comparative experiments revealed that LAS was more favorable for the formation of ASA than Bronsted acidic sites (BAS). Furthermore, a plausible mechanism for the acetylation of SA and AA by Y-CER has been proposed. This work provided a practical protocol for improving ASA yield and reducing acid wastewater discharge, with potential application prospects. [ABSTRACT FROM AUTHOR]

The aim of the current study is to modify water hyacinth fibre (WHF), which are then used to produce novel oil sorption polymers. Two synthetic materials were derived from acetylation by acetic anhydride using N-bromosuccinimide (NBS) as a catalyst and the graft co-polymerisation of butyl acrylate (BA) using 2,2′-azobisisobutyronitrile (AIBN) as an initiator. Physicochemical properties were comprehensively characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, contact angle, and thermogravimetric analysis. In the seawater/crude oil system, the best oil sorption capacity values of the raw WHFs and their acetylated-WHF and graft co-polymer WHF-g-BA were 7.46 g/g, 20.16 g/g, and 25.47 g/g, respectively. The sorption kinetic and isotherm studies exhibited that the oil sorption of the co-polymer WHF-g-BA is ruled by pseudo-second-order kinetic and Freundlich isotherm models. The reusability of the WHFs and their synthetic materials has reached 6 cycles of sorption/desorption, and this property of the co-polymer is always better than that of acetylated and original fibres. [ABSTRACT FROM AUTHOR]

A composite based on Fe3O4 nanoparticles, graphene oxide, and a ionic liquid (1-butyl-3-methylimidazolium-2-carboxylate) is proposed as a sorbent for the extraction of bisphenol A (BPA) from bottom sediments by matrix solid-phase dispersion (MSPD). The saturation magnetization of the synthesized sorbent is 34 emu/g. Grinding of bottom sediments and subsequent grinding with a sorbent was carried out in a ball mill. Some stages of MSPD were partially automated, in particular, the procedures of magnetic separation, BPA desorption, and sorbent regeneration. The recovery of BPA under the experimentally selected conditions (sorbent mass 0.5 g, time required to grind the sorbent 5 min) was 94%. The sorbent can withstand four sorption-desorption cycles without a loss of sorption capacity. To purify the matrix from interferents, washing with n-heptane was proposed. Bisphenol A was determined by gas chromatography–mass spectrometry after derivatization with acetic anhydride. The analytical characteristics of the method were established using model samples of bottom sediments artificially contaminated with BPA. The limit of determination using the developed method is 0.1 μg/kg, the linearity range of the calibration curve is 0.3–12 μg/kg (r2 = 0.994). As real samples for analysis, we used bottom sediments selected near the discharge of wastewater treatment plants in the city of Voronezh (Voronezh River and Don River). The BPA concentration in bottom sediments is 3.83–6.52 μg/kg. [ABSTRACT FROM AUTHOR]

A series of substituted 2-aminotetrahydroquinolinecarbonitriles have been synthesized by the three-component condensation of diaryl(hetaryl)methylidenecyclohexanones, malononitrile, and ammonium acetate. Factors responsible for the reaction selectivity and product formation pathway have been revealed. The reaction of aminoquinolinecarbonitriles with acetic anhydride under acidic conditions afforded substituted hexahydro-pyrimido[4,5-b]quinolinones. The structure of the synthesized compounds has been determined by IR and 1H and 13C NMR spectroscopy, including HSQC two-dimensional correlation technique. [ABSTRACT FROM AUTHOR]

Bulk heterojunction solar cells are among the most promising organic solar cells (OSCs). One of the two important parts of OSCs are acceptors, and the development of the design and synthesis of non-fullerene acceptors involves an electron-deficient heterocyclic central core and anchor acceptor malonitrile derivatives of 3-methylene-2,3-dihydro-1H-inden-1-ones. In this communication, an intermediate for the synthesis of this compound, 1-(dicyanomethylene)-3-hydroxy-1H-indene-2-carboxylic acid, was prepared by the Perkin reaction of 2-(3-oxoisobenzofuran-1(3H)-ylidene)malononitrile with tert-butyl acetoacetate in the presence of acetic anhydride and triethylamine. The structure of the newly synthesized compound was established by means of elemental analysis, high-resolution mass spectrometry, 1H NMR, 13C NMR and IR spectroscopy, and mass spectrometry. [ABSTRACT FROM AUTHOR]

A series of some new 1,3,4‐oxadiazole derivatives was synthesized. Hydrazide derivative 4 was reacted with some sugar aldehydes to give the corresponding sugar hydrazones 5 a–c. Acetylation of 5 a–c with acetic anhydride in pyridine, managed the per‐O‐acetyl derivatives 6 a–c while refluxing in acetic anhydride gave the corresponding 1,3,4‐oxadiazolines 7 a–c. On the other hand, 1,3,4‐oxadiazoles 8 a,b, 9, 10, 12, 14, and 15 were synthesized via the reaction of 4 with different reagents including p‐chlorobenzoic acid, nicotinic acid, methyl iodide, morpholine, phenyl isothiocyanate, potassium iodide, chloroacetyl chloride, and phosphorus oxychloride, respectively. The new compounds were assessed for their anticancer and antioxidant activities. Compounds 8 a,b, 10, and 12–15 displayed the most antioxidant activity. In addition, compounds 8 a, 8 b, and 13 showed strong cytotoxic activity. [ABSTRACT FROM AUTHOR]

The reaction of p-aminophenol with acetic anhydride under microwave irradiation in the presence of H-clinoptilolite was studied to continue the search for effective, economically favorable, and environmentally friendly methods for synthesizing acetaminophen (paracetamol). The proposed system, which provided a rapid synthesis of the most important drug with a high yield and purity, was demonstrated to be efficient. [ABSTRACT FROM AUTHOR]

Summary: Proteins are commonly used ingredients to impart certain non‐nutritional properties to foods. Consequently, the industry is constantly seeking to enhance proteins that provide these attributes to food products. Therefore, the aim of this research was to extract the protein from sesame seeds and evaluate the effect of chemical modification through acylation with lauroyl chloride and acetic anhydride on functional properties (solubility index, emulsifying, foaming, swelling and water‐holding and oil‐holding capacity). Chemical modification was successfully demonstrated using FTIR spectroscopy and X‐rays. It was found that acylation with lauroyl chloride or acetic anhydride altered the physicochemical and functional properties, particularly at pH 10. Both reactions exhibited substitution degrees exceeding 20%. Chemical modification via acylation resulted in significant improvements in water and oil retention capacity, emulsifying activity and foaming activity. Thermal analysis revealed significant changes in the modified samples, altering their denaturation temperature, leading to the conclusion that chemical modifications through acylation with lauroyl chloride or acetic anhydride offer benefits in certain functional properties relevant to the food industry. They also represent an opportunity to diversify the application of a by‐product obtained from sesame oil extraction. [ABSTRACT FROM AUTHOR]

This paper presents a novel and reliable approach for the determination of tilmicosin residues in poultry muscle and pork via gas chromatography–tandem mass spectrometry after precolumn derivatization. The samples were subjected to a quick, easy, cheap, effective, rugged, and safe preparation method, solid-phase extraction, hydrogenation, gel chromatography separation, acid hydrolysis, and derivatization with pyridine and acetic anhydride. For the blank spiked samples at the limit of quantification, 0.5 times the maximum residue limit (MRL), the MRL, and 2.0 times the MRL, the recoveries were from 76.91 to 87.99% with a precision of 2.04–5.47%. The limits of detection and quantification were 2.3–4.4 and 6.2–9.8 µg kg−1, respectively. The protocol was validated and real samples analyzed to demonstrate its practical application. [ABSTRACT FROM AUTHOR]

The reaction of ethyl pyridine-2-ylcarbamate with phenacyl bromides in acetonitrile gave 2-aryl-1-(ethoxycarbonyl)-2-hydroxy-2-phenyl-2,3-dihydro-1H-imidazo[1,2-a]pyridine-4-ium bromides which were con--verted into 2-arylimidazo[1,2-a]pyridines by heating in acetic anhydride, followed by treatment with potassium carbonate. [ABSTRACT FROM AUTHOR]

BACKGROUND: Collagen is a biomedical material with good biocompatibility, low toxicity, low immunoactivity, and high cellular affinity. However, the defects such as hydrophilicity and poor thermal stability are the key technical problems that need to be solved urgently in biomedical, tissue engineering, and other applications. OBJECTIVE: To elaborate on the preparation method, characterization, and application progress of acylated collagen. METHODS: PubMed, X-mol, and CNKI databases were used to search the literature on acylated collagen preparation methods, characterization, and application. The search time was from January 1992 to May 2023. The English search terms were “acylated collagen, modified collagen, water-soluble collagen, acetic anhydride”. Chinese search terms were “acylated collagen, modified collagen, water-soluble collagen”. After an initial screening of all articles according to inclusion and exclusion criteria, 53 articles with high relevance were retained for review. RESULTS AND CONCLUSION: (1) The preparation of acylated collagen is mainly obtained by the acylation reaction of acid anhydride, and the reaction sites are mainly ε-amino and N-terminus-amino of collagen, and the reaction environment of acylation reaction needs to be carried out in an alkaline environment. (2) Succinic anhydride is the preferred reactant of acylated collagen. Carbonic anhydride, citric anhydride, and bifunctional modifiers with acylation ability have been excavated in recent years to meet various requirements, but it is still limited to laboratory preparation; complex preparation process is difficult to industrialize, and follow-up research is needed to continuously improve. (3) The characterization methods of acylated collagen are similar to those of collagen, but there is still a lack of standards for the water-soluble characterization of acylated collagen. (4) In recent years, acylated collagen has been gradually used in the preparation of lenses, hydrogels, and dressings, as well as cosmetic raw materials. However, there is still little research on the application of acylated collagen, and there is a lack of complete in vivo experiments to verify the practicality of acylated collagen. [ABSTRACT FROM AUTHOR]

Diboradiazene compounds, derived in one step from the boron‐mediated reduction of dinitrogen (N2), were treated separately with sulfur and acetic anhydride, providing heterocyclic compounds that are BN isosteres of thiophene and 1,3‐oxazole, respectively. These simple reactions represent the final steps in two‐step routes to complex heterocycles from N2 that both circumvent the need for transition metal reagents and completely bypass the traditional intermediate ammonia. [ABSTRACT FROM AUTHOR]

BACKGROUND: Starch is the main component of quinoa seeds. However, quinoa starch has poor solubility in cold water and poor mechanical resistance and is easily aged, which limit its application. Therefore, modification of its structure to improve its functional properties is necessary. RESULTS: This research used acetic anhydride and sodium trimetaphosphate to modify the structure of starch molecules and investigated their influence on bread quality. The results showed that both esterification and crosslinking prevented the aggregation behavior of starch molecules. Moreover, they both decreased the gelatinization enthalpy change and relative crystallinity of the starch. Compared with native starch, modification significantly decreased the gelatinization temperature from 57.01 to 52.01 °C and the esterified starch exhibited the lowest enthalpy change with a 44.2% decrease. Modified starch increased the specific volume and decreased the hardness and chewiness of bread. Modification did not influence the moisture content in bread but impacted the water retention capacity, depending on the degree of modification. Low and medium degrees of modification improved the water retention capacity during storage. By contrast, a high degree of modification (10 g kg−1 crosslinking agent) decreased the water retention capacity. The dually modified quinoa starch (esterified and crosslinked) showed no influence on the textural properties of bread. CONCLUSION: This study demonstrated that both esterification and crosslinking significantly improved the functional properties of quinoa starch. Crosslinked or esterified quinoa starches have the potential to improve the textural properties of bakery products. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The mechanochemical hydrogenation of 4-nitrophenol was examined in a ball mill reactor. Hydrogen gas flows through the reactor at ambient temperature and pressure in the presence of Pd/C catalyst and acetic anhydride. Under optimized conditions, simultaneous hydrogenation and acetylation in one pot increased paracetamol selectivity by avoiding undesirable side reactions of 4-aminophenol. Side product formation was further reduced through a novel bubbler configuration allowing for the delivery of acetic anhydride vapor to the reaction vessel. Ball mill results were compared to traditional stirred tank hydrogenations in a Parr reactor and shown to have superior yield and process mass intensity. [ABSTRACT FROM AUTHOR]

The significant medicinal and pharmacological facts about chromenes (benzopyran) nucleus prompted us to focus on constructing unique chromenes with biological value. New chromene derivatives 2–15 were synthesized, and their antibacterial effectiveness was studied. The reaction of the 2-amino-4H-chromene derivative 1 with a variety of reagents such as acetic anhydride, formic acid, chloroacetyl chloride, cyclopentanone, ethyl acetoacetate, diethyl malonate, aldehydes, and isatin produced derivatives 2–13. Compound 1 was also treated with aromatic amines such as p-toluidine and/or benzene-1,4-diamine with formaldehyde, yielding derivatives 14 and 15, respectively; spectral techniques were used to confirm the predicted structures of all compounds. The antibacterial activity of the recently synthesized compounds was assessed against two types of bacteria, Bacillus subtilis and Escherichia coli. There is encouraging antibacterial activity in compounds 5 and 7. [ABSTRACT FROM AUTHOR]

The objectives of this study are to investigate the structural and physicochemical properties of a novel acetylated lotus seed starch (LSA). LSA is successfully prepared using an aqueous phase method. Fourier transform infrared spectroscopy (FTIR) proves that a carbonyl C=O vibration at 1737 cm−1 are due to the introduced acetyl groups. X‐ray diffraction (XRD) indicates that the acetylation treatment does not change the crystal structure, but reduces the relative crystallinity of starch. Scanning electron microscopy (SEM) shows that the surface of LSA with 12% of acetic anhydride (LS‐12A) becomes the roughest. Moreover, compared with lotus seed starch (LS), the particle size, transparency, swelling power, and solubility of LSA are increased to 18.01 ± 0.66 µm, 15.30% ± 0.30%, 9.59 ± 1.78 g g−1, and 6.06% ± 0.99% at 55 °C with the additional content of acetic anhydride. However, differential scanning calorimetry (DSC) shows that the melting enthalpy of LSA decreases compared with LS. This work provides some theoretical basis for the study and development of acetylated starch. [ABSTRACT FROM AUTHOR]

A novel series of 1,3,4-oxadiazole derivatives of mefenamic acid was obtained by reacting hydrazones of mefenamic acid with anhydrous acetic anhydride. The mefenamic hydrazones were obtained by reacting different substituted aldehydes with mefenamic acid hydrazide. All the compounds were characterized by spectral data and elemental analysis. Molecular docking studies of all the compounds were performed against COX-1/COX-2 enzymes. Compound 4 and compound 10 were found to have the highest potential to bind with COX-1 while compound 3, compound 6, and compound 10 were found to have the highest potential to bind with COX-2 enzyme. [ABSTRACT FROM AUTHOR]

This report expresses a sustainable methodology for the in situ synthesis of Ag nanoparticles (NPs) adorned carboxymethyl lignin (CML) functionalized Fe3O4 nanocomposite (Fe3O4@CML/Ag) and its subsequent chemical and biological applications. Structural and physicochemical features of such novel material was evaluated through a number of analytical techniques like FT-IR, FE-SEM, TEM, EDS, XRD, ICP and VSM. The nanomaterial was a competent catalyst towards the N-acylation of diverse amines using acetic anhydride at solvent-free conditions. The material was isolated by magnet and reused for 8 consecutive times. Furthermore, the material was employed in the biological evaluation of anti-oxidant properties by DPPH method as well as the anticancer studies of against HT-29 and Caco-2 colon cell lines following MTT method. The DPPH assay afforded a significant IC50 value that suggested the material to have good anticancer properties. Interestingly, % cell viability of the malignant cell lines was found to decrease dose-dependently over Fe3O4@NaLS/Ag nanocomposite. MTT assay afforded the corresponding IC50 values to be 395.4 μg/ml and 287.3 μg/ml respectively against the two cell lines. The absorbance rate was evaluated at 545 nm, which represented toxicity on normal cell line (CHO) even up to 2000 μg/mL. [ABSTRACT FROM AUTHOR]

BACKGROUND: Wheat bran is rich in dietary fiber (DF), particularly insoluble dietary fiber (IDF). Although the benefits for human health following the consumption of these DFs have been documented, the lower water retention capacity (WRC) and other properties still limit the applications of DF. Therefore, the current research investigated the impact of acetylation on the changes in the corresponding physicochemical and functional properties of DF. RESULTS: The current results indicated the acetylated group restricted the alignment of the molecular chains, which led to an increased amorphous phase in the fiber structure, followed by an enhanced thermal sensitivity and a reduced crystallinity as evidenced by X‐ray diffraction (XRD). Moreover, the acetylation of the IDFs enhanced the cholesterol absorption capacity, but the corresponding antioxidant capacity and cation exchange capacity were reduced, which might be due to the partial loss of the phenolic compounds onto the polysaccharides during the modification. Interestingly, a lower degree of substitution (DS) of the IDF achieved from water‐acetic anhydride modification led to a higher WRC and water swelling capacity (WSC). In contrast, a higher DS from acetic anhydride modification demonstrated a greatly improved in vitro hypoglycemic performance of the IDF, including α‐amylase inhibitory activity and glucose dialysis retardation index (GDRI), compared to the other samples. CONCLUSION: This study highlights a new approach to modify the functionality of IDFs via acetylation and the design of a novel IDF with hypoglycemic activity. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A phosphine, base and additive free cross-coupling of arylboronic acid is reported via C–O bond cleavage of acetic anhydride using a switchable ferrocene functionalized n-heterocyclic carbene (NHC) palladium complex. The novel redox active catalytic system afforded the corresponding arylketones with good to excellent yields. [ABSTRACT FROM AUTHOR]

Functionalized ionic liquids (FILs) are efficient ILs for the protection of various functionalities such as aldehydes, phenol, and alcohols with acetic anhydride under neat conditions. The attracted rising interest and the subject of active research in the field of catalysis is the variety of expanded applications and yet reports on ILs are still quickly increasing. This work reports a sulfonic acid functionalized ionic liquid is an environmentally friendly, easy handling, and reusable ionic liquid catalyst for the protection of aldehydes and phenols. The catalyst was characterized with different spectroscopic techniques which indicates the fabricated IL is matching with the reported methods. The catalyst can be recycled up to eight times without substantial loss in activity. Furthermore, no chromatographic separations were needed to obtain the desired products. [ABSTRACT FROM AUTHOR]

Five chromone and a-pyronochromone derivatives have been synthesized by reaction of ohydroxyacetophenones and o-acetylhydroxycoumarins with anhydride acetic and sodium acetate as a catalyst. Then, these derivatives reacted with some aromatic aldehydes and received fourteen new bis(arylidenes). Furthermore, the intermediate product resulting from the reaction of 3-acetyl-7-methoxy-2-methylchromone and p-hydroxybenzaldehyde was successfully isolated and identified as 7-methoxy-2-methyl-3-[(2'E)-3'-(phydroxyphenyl)- prop-2'-enoyl]chromone. The antioxidant activity of all compounds was evaluated. The results show that 2-(4-hydroxystyryl)-3-((E)-3-(4-hydroxyphenyl)prop-2-enoyl)-7-methoxychromone has the highest antioxidant activity in tested compounds with inhibition of 88.48% at 50 µg/mL. [ABSTRACT FROM AUTHOR]

In this paper, we present the synthesis of new selenoloquinoxaline derivatives starting from 2‐chloroquinoxaline‐3‐carbonitrile 1. The compound 1 was subjected to a reaction with selenium metal in the presence of NaBH4 as a reducing agent in ethanol, under a nitrogen atmosphere. This reaction resulted in the formation of the sodium salt of 3‐cyanoquinoxaline‐2‐selenolate, which was subsequently reacted with α‐halogenated carbonyl compounds in situ. This reaction produced a series of newly synthesized 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐substituents. Ethyl 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐carboxylate 3a was hydrolyzed by sodium hydroxide to give the corresponding sodium salt 9. This salt was then refluxed with acetic anhydride to produce oxazinone compound 10. The reaction of compound 10 with ammonium acetate afforded pyrimidoselenolo[2,3‐b]quinoxaline derivative 11. Compound 11 was then chlorinated using phosphorous oxychloride to give the corresponding chlorocompound. [ABSTRACT FROM AUTHOR]

This study was the first-ever attempt to apply MIL-68 (Ga) in developing an analytical method. The method extracts and preconcentrates some parabens from mouthwash and hydrating gel samples. The variable extraction parameters were optimized, and the figures of merit were documented. Avogadro software was used besides discussing intermolecular interactions to clarify the absorption process. ComplexGAPI software was also exploited to assess the greenness of the method. After the derivatization of the parabens using acetic anhydride in the presence of sodium carbonate, sodium chloride was added to the solution and vortexed to dissolve. A few milligrams of MIL-68 (Ga) were added into the solution and vortexed. Centrifugation separated the analyte-loaded absorbent, which was treated with mL volume of methanol through vortexing for desorption aim. A few microliters of 1,2-dibromoethane were merged with the methanolic phase and injected into a sodium chloride solution. One microliter of the extracted phase was injected into a gas chromatograph equipped with a flame ionization detector. High enrichment factors (200–330), reasonable extraction recoveries (40–66%), wide linear ranges (265–30,000 µg L−1), and appreciable coefficients of determination (0.996–0.999) were documented. The applicability of dispersive solid phase extraction for extracting polar analytes, imposing no additional step for performing derivatization, the capability of MIL-68 (Ga) for the absorption of both derivatized and non-derivatized parabens, the use of only 10 mg absorbent, and one-pot synthesis besides no high temperature or long reaction time in the sorbent provision are the highlights of the method. [ABSTRACT FROM AUTHOR]

A new series of benzoquinoline-based heterocycles was synthesized utilizing the building block synthon, 2-((3-chlorobenzo[f]quinolin-2-yl)methylene)hydrazine-1-carbothioamide via the condensation of 3-chlorobenzo[f]quinoline-2-carbaldehyde with thiosemicarbazide. The titled thiosemicarbazone scaffold was conducted with some carbon-centered electrophilic reagents such as acetic anhydride, chloroacetyl chloride, chloroacetic acid, 2-bromo-1-(3-nitrophenyl)ethan-1-one, 2-chloro-N-phenylacetamide, and dimethyl but-2-ynedioate to achieve triazolethione, imidazolone, thiazolidinone, and thiazole derivatives. In turn, the hydrazinolysis of this substrate did not proceed as expected but it afforded the azine derivative. The antioxidant activity screening of the produced compounds revealed that thiazole and triazolethione derivatives were the most potent. [ABSTRACT FROM AUTHOR]

Hierarchical Beta zeolites with interconnected intracrystalline mesopores and high structural stability are highly attractive for catalytic applications involving bulky reactants. Here, by introducing a suitable amount of polydiallyldimethylammonium chloride into the initial synthesis system, micron-sized Beta zeolite crystals with abundant hierarchical porosity (Beta-H) were hydrothermally synthesized. The sample named Beta-H_1 exhibited very high catalytic activity and durability for the Friedel–Crafts acylation of anisole with acetic anhydride. A 92% conversion rate of acetic anhydride could be achieved after 1 h of reaction in a fixed bed reactor, and 71% conversion still remained after 10 h, much better than the rate for conventional Beta zeolite (which decreased rapidly from 85% to 37% within 10 h). The enhanced catalytic performance of Beta-H zeolites could be mainly attributed to the relatively lower strong acid density and the faster transport rate of the hierarchical zeolites. In addition, Beta-H showed high structural stability and could be easily regenerated via high-temperature calcination without obvious loss in catalytic activity, demonstrating its great potential for catalytic applications in the industrially important Friedel–Crafts acylation process. [ABSTRACT FROM AUTHOR]

In order to improve process safety, product purity, and production efficiency in the synthesis of N-n-butyl-N-(2-nitroxy-ethyl)nitramine (BuNENA), a two-stage continuous flow microreactor system was constructed by sequentially connecting the self-designed heart-shaped channel microreactor and the caterpillar microreactor. n-Butylethanolamine was used as the raw material, nitric acid and acetic anhydride were used as the nitrating agents. The results showed that when the flow rate of n-butylethanolamine was 1.00 mL.min− 1, the temperature of the heart-shaped channel microreactor was 10 ℃, the temperature of the caterpillar microreactor was 35 ℃, the molar ratio of ZnCl2 to n-butylethanolamine was 2%, the molar ratio of nitric acid to n-butylethanolamine was 2.4, and the molar ratio of ZnCl2 to n-butylethanolamine was 2.4, the result was best. Under the conditions, the reaction time was shortened to 300 s, the purity of BuNENA was up to 98.1%, and the yield was 87.1%. [ABSTRACT FROM AUTHOR]

In this research, the ionic liquid 4-methylpyridinium chloride grafted on nanoporous Ni/zeolite-Y was fabricated in several steps. Firstly, the nanocomposite of nickel-zeolite–Y (Ni@ZY) was prepared from the exchange-metal reaction of nickel (II) chloride with zeolite-NaY. This nanomaterial was then reacted consecutively with trimethoxysilyl propyl chloride and 4-methylpyridine to obtain nanocomposite of Ni/[(MPy)+Cl−]@ZY. Then, Fe3O4 nanoparticles were produced inside the functionalized zeolite pores with the use of ultrasonic waves to prepare a multi-functional and magnetically 4-methylpyridinium ionic liquid-nickel nanosystem (Ni/[(MPy)+Cl−]@ZY-Fe3O4). Its structure was identified and confirmed by various analyses including: FT-IR, FE-SEM, TEM, EDX, XRD, TGA, VSM and N2 adsorption–desorption (BET). To evaluate the catalytic performance, it has been successfully employed as a nanocatalyst, in facile Erlenmeyer synthesis of 4-arylidene-2-phenyl-5(4H) oxazolones (azlactones) through the multi-component reaction of benzoyl chloride, glycine, arylaldehydes and acetic anhydride under mild conditions. The presence of basic ionic liquid (4-methylpyridinium chloride), Lewis acid (Ni2+) on the solid surface of nanoporous (multifunctional) and the easy separation of the nanocatalyst from the reaction medium by an external magnet are the most distinguished advantages of this procedure. These points can be beneficial and effective in the catalytic processes. Some other advantages of the present process are high product yields, high-speed reaction rate, application of nanotechnology in the catalytic process, catalyst recyclability, low cost and non-toxicity. [ABSTRACT FROM AUTHOR]

Using salicylic acid and acetic anhydride as raw materials, silica gel as a catalyst, and microwave technology as an optimization method, the university organic chemistry teaching experiment of 'Preparation and Characterization of Acetylsalicylic Acid' was improved. Through the experiment, the impact of factors such as microwave power, reaction time, and raw material ratio on the final yield was explored. The optimal experimental conditions were determined as follows: silica gel with a particle size of 100-200 mesh, 0.25 g in quantity, 60 s reaction time, 70 °C reaction temperature, 500 W microwave power, and a molar ratio of acetic anhydride to salicylic acid of 2 : 1. The average yield was approximately 68.0%. Compared to the conventional heating method for the preparation of acetylsalicylic acid, microwave-assisted synthesis offers advantages such as simplicity, shorter reaction time, higher product yield, fewer impurities, and environmental friendliness. Introducing this microwave experiment into undergraduate organic chemistry laboratory teaching can broaden students' horizons, enrich experimental teaching content, and further improve the teaching level. [ABSTRACT FROM AUTHOR]

To alleviate the global warming, it is necessary to transform carbon dioxide (CO2) into carbon monoxide (CO) through an expedient and resultful approach. In this work, a novel kind of Schiff base-cobalt ion complexes (CHE-Co) was constructed with 5-chorosalicylaldehyde, acetylglycine, acetic anhydride and CoCl3·6H2O as raw materials. It was discovered that CHE-Co exhibits outstanding photocatalytic activity to reduce CO2 to CO (selectivity: 91%) in an H2O/CH3CN solution (V:V = 1:4) under the irradiation of a LED-simulated solar lamp (λ > 400 nm, 90 mW cm–2). Under the optimized conditions, the yield of CO photo-catalytically reduced from CO2 can reach 15.92 μmol, with TON value of 1592 and TOF value of 159.2 h−1. The photo-catalytic mechanism of CHE-Co was proposed that CHE-Co with a positive Eonset can drive electrons shift from excited-state photosensitizer [Ru(phen)3]2+* to CHE-Co via a single-molecule rate control reaction. [ABSTRACT FROM AUTHOR]

Chemical modification of starch from the chayote root (Sechium edule Jacq) is carried out with lauric acid and acetic anhydride. The modified starch is characterized by Fourier‐transform infrared spectrometry (FTIR), X‐ray diffraction (XRD), and Differential Scanning Calorimetry (DSC) and used to formulate edible films. The developed edible films are characterized based on their physicochemical and mechanical properties. The physicochemical and functional properties of starch are affected by the incorporation of the acyl and acetyl group. Both starches exhibit a significant decrease in solubility. Starch modified by the incorporation of the acyl group (lauroyl) has higher thermal stability than starch modified by the incorporation of the acetyl group. The first shows an increase in emulsifying and foaming capacity, as well as water‐ and oil‐retention capacity, while the second exhibits adequate edible film‐forming properties. The edible films develop with modified starch with acetyl group has a homogeneous surface and exhibit a higher percentage of elongation at break when they are stored at a water activity of 0.561. In accordance with the above, it is concluded that the chayote root starch modified has physicochemical and functional properties that indicate their potential utility in the food industry. [ABSTRACT FROM AUTHOR]

The present work describes an efficient and convenient synthesis of a library of novel 1, 2-bis- (tetrasubstituted-benzylidene) hydrazine an analogue (3-7) 1,2-bis (3-methoxy-2-hydroxybenzlidene) hydrazine (3) and 1,2-bis (6-bromo-3-methoxy 2-hydroxybenzylidene) hydrazine (4), were obtained via opening of ester coumarin derivatives (1 and 2) with hydrazine hydrate under reflux. Diazotization of compound 4 with aryldiazonium chloride led to the formation of 1,2-bis (6-bromo-5-arylazo-3-methoxy-2-hydroxybenzylidene) hydrazine (6a,b). Acetylation of compounds 4 and 6a with acetic anhydride afforded the corresponding 1,2-bis (6-bromo-5-substituted-3-methoxy-2-acetoxy benzylidene) hydrazines (5 and 7). The cytotoxicity screening of some synthesized 1,2-bis (tetra substituted benzylidene) hydrazines (4-7) against breast cancer cell lines (MCF-7), and it was found several active compounds. Meanwhile compound 5 exhibited cytotoxic activity compared to reference drug. The DNA flow cytometry on MCF-7 cells of compound 5 was determined, it was found to cause G2/M phase arrest and induce apoptosis in all G1/M phases. In addition, compound 5 has been tested in other trials against aromatase inhibitors and tyrosinase inhibitors. [ABSTRACT FROM AUTHOR]

Objective: The present contribution describes a novel approach for obtaining steroid derivatives of the iso-type from sapogenins for drug discovery. Methodology: Diastereomeric 23-acetyl-spirostanols were prepared by acetolysis of smilagenin (4) (25R) using boron trifluoride diethyl etherate in acetic anhydride followed by treatment of the epimeric epoxycholestene obtained (6 or 9) under basic hydrolysis. Higher regioselectivity was attained in the presence of ZnCl2 in acetic anhydride. Results: Acetolysis of smilagenin (4) (25R) using boron trifluoride diethyl etherate in acetic anhydride afforded 20-α-methyl epoxycholestene 6 as the major product, two furostene derivatives (7 and 8), as well as the new 20-β-methyl epoxycholestene 9. Increased regioselectivity for the acetolysis of smilagenin (4) was observed using ZnCl2 in acetic anhydride affording 6 in 90% yield. Subsequent treatment of the epimeric epoxycholestene (6 or 9) under basic hydrolysis afforded two new diastereomeric 23-acetyl-spirostanols 14 and 15. The structures of all compounds were established using 1D and 2D NMR techniques. Conclusions: Formation of the two diastereomeric 23-acetyl-spirostanols (14 and 15) from epimeric epoxycholestenes 6 and 9 with KOH/EtOH proceeds with high stereospecificity. The configuration at C-20, C-22, C-23, and C-25 for the new iso-type 23-acetyl-spirostanol 15 was established by X-ray crystal analysis as 20R, 22R, 23S, and 25R. In addition to the above, the X-ray of 15 was analyzed and compared with the crystallographic data of sarsasapogenin acetate (16), smilagenin (4) and 23-acetyl-sarsasapogenin (17). [ABSTRACT FROM AUTHOR]

Formic acid, activated by acetic anhydride and a base, was employed as a CO surrogate to deoxygenate nitroarenes to nitrosoarenes, a reaction catalyzed by a palladium/phenanthroline complex in the homogeneous phase. Nitrosoarenes were trapped by conjugated dienes to give 3,6‐dihydro‐2H‐[1,2]‐oxazines. The latter were then transformed into N‐arylpyrroles employing CuCl as the catalyst. The reaction was designed to give the best results for pyrroles lacking any substituent in the 2 and 5 positions, which are difficult to produce employing most pyrrole syntheses. [ABSTRACT FROM AUTHOR]

Among oxygen-containing heterocyclic compounds such as coumarin and azacoumarin derivatives, the scaffold has become an important construction motif for developing new drugs. Coumarin and its derivatives possess many types of biological activities and have been reported to show significant cytotoxic activity. N-(6,8-disubstituted coumarin-3-yl)benzamides (8a-c) namely (3-N-(benzoyl) aminocoumarin-6-ylmethyl acetate (8a); N-[6-(1-acetylpyrazol-3-yldiazineyl) coumarin-3-yl] benzamide (8b); N-(8-methoxy-6-bromo-coumarin-3-yl) benzamide (8c), were synthesized via a cyclocondensation reaction of 5-(chloromethyl)-2-hydroxybenzaldehyde (3), 5-(pyrazol-3-yl-diazineyl)-2-hydroxybenzaldehyde (4), and 5-bromo-3-methoxy-2-hydroxybenzaldehyde (5) with N-benzoylglycine (7), in good yield. Treatment of compound 8c with ammonia in the presence of anhydrous potassium carbonate to yield N-(5-bromo-8-methoxy-1-azocoumarin-3-yl) benzamide (9). Compound (9) was acetylated with acetic anhydride to give N-(2-acetoxy-5-bromo-8-methoxyquinolin-3-yl) benzamide (10). N-(substituted coumarin and azacoumarin-3-yl) benzamides (8-10) were tested for their in vitro cytotoxic activity against (HepG2) cell line. Furthermore, DNA flow cytometry investigation over HepG2 cells indicated that compound 8a demonstrated arrest at G1/S stages of the cell cycle and induction of apoptosis by rising pre-G1 stage. Compound 8a displayed a significant tubulin polymerization inhibition. [ABSTRACT FROM AUTHOR]

The 2-[2-(1-(4-chlorophenyl)ethylidene]hydrazineyl-1,3-thiazolidin-4-one (V) compound was synthesized via the condensation of thiosemicarbazone derivatives (III) with chloroacetyl chloride which gave a 1,3-disubstituted thiourea derivative (IV) as an intermediate compound, this was followed by cyclization of (IV) in situ boiling ethanol solvent in the presence of anhydrous potassium carbonate. The treatment of thiazole derivative (V) with 4-hydroxybenzaldehyde yielded the corresponding 2,5-disubstituted-1,3-thiazolidin-4-one (VI). Compound (VI) was reacted with 4-chlorophenacyl bromide that afforded 5-(4-hydroxybenzylidene)-2-(1,2-disubstituted) hydrazineyl-1,3-thiazolid-in-4-one (VIII). Acetylation of compounds (VI) and (VIII) with acetic anhydride formed acetyl derivatives (VII) and (IX). The structures of synthesized compounds were characterized and confirmed based on spectroscopic methods and microanalytical method (elemental analysis). It was found that most of the 1,3-thiazole derivatives (V–IX) showed enzyme activity, while compound (VIII) exhibited an excellent activity with IC50 value (4.22 μM) for α-amylase. Also, compound (VIII) gave a good inhibitory activity against free radical scavenging (DPPH), DPP-4, and human breast cancer (MCF-7). Based on the achieved results, it was suggested that compound (VIII) acts as a vital structure for the development of the most potent α-amylase inhibitors. [ABSTRACT FROM AUTHOR]

Application of bioisostere plays an important role in drug discovery. α‐Aminoboronic acid is the familiar bioisostere of α‐amino acid. Developing reactions for the synthesis of a wide variety of α‐aminoboronic acid is one important task for synthetic chemistry. Herein, we report the development of nucleophilic C‐borylation chemistry for N‐arylimines catalyzed by nickel. The reaction proceeds through the insertion of a borylnickel species into the C=N bond to afford the corresponding α‐aminoboronate, which was isolated as acetamide after trapping with acetic anhydride. N‐Benzyl imine is also tolerated by the developed reaction. [ABSTRACT FROM AUTHOR]