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Starch is the main predominant food reserve in plants. Its characteristics stand out from other carbohydrates providing it with several industrial applications. However, the starch is chemically modified in order to improve and extend these aspects. The objective of this study was the characterization of unconventional starch from the modification by acetylation of white inhambu starch (Dioscorea trifida L.), in order to verify its possible applicability. Chemical, physicochemical, thermal, morphological, structural and technological properties were characterized. Chemical modification with acetic anhydride resulted in a low degree of acetyl group substitution, with 0.076. Starch was found to have high apparent amylose content and purity due to low ash, protein and lipid values. Thermogravimetric analysis of the modified starch showed stability in the temperature range from 120 to 255 °C, granule morphology showed spherical and smooth surface shapes ranging in size from 8.08 to 19.23 μm. The introduction of the functional group was confirmed by infrared spectroscopy at 1246 cm−1 and 1717 cm−1. The acetylation treatment presented high solubility index and, swelling power in relation to temperature and transparency of the paste in relation to time. It is concluded from the modification of white inhambu starch that its various characteristics may be intended for different segments of the food industry. [ABSTRACT FROM AUTHOR]

Acetolysis is an important stage in the sample treatment for pollen analysis. However, since 1998, acetic anhydride (CH3CO)2O, used for the acetolysis solution preparation, refers to precursors which turnover is limited in Russia and its use needs measures for special control. We suggest replacing acetic anhydride with propionic anhydride (CH3CH2CO)2O, for which there are no such limitations. The procedure of sample treatment with propionic anhydride is the same as one with acetic anhydride. Testing an acetolysis procedure using propionic anhydride on peat samples collected in the Kaluzhskie Zaseki State Nature Reserve shows the high efficiency of this chemical agent.

Considering the remarkable relevance of acetylated derivatives of phenols, alcohols, and aryl and alkyl thiols in different areas of biology, as well as in synthetic organic chemistry, a sustainable solvent-free approach to perform acetylation reactions is proposed here. Acetylation reactions are classically performed using excess of acetic anhydride (Ac2O) in solvent-free conditions or by eventually working with stoichiometric amounts of Ac2O in organic solvents; both methods require the addition of basic or acid catalysts to promote the esterification. Therefore, they usually lead to the generation of high amounts of wastes, which sensibly raise the E-factor of the process. With the aim to develop a more sustainable system, a solvent-free, stoichiometric acetylation protocol is, thus, proposed. The naturally occurring phenol, thymol, can be converted to the corresponding—biologically active—ester with good yields, in the presence of 1% of VOSO4. Interestingly, the process can be efficiently adopted to synthesize other thymyl esters, as well as to perform acetylation of alcohols and aryl and alkyl thiols. Remarkably, a further improvement has been achieved replacing Ac2O with its greener alternative, isopropenyl acetate (IPA).

An optimized multi-step synthesis of a new highly effective and low-toxicity derivative of o-benzoylaminobenzoic acid amides possessing anxiolytic activity is presented. Anthranylamide and propionic anhydride instead of acetic anhydride were used as starting materials. The number of synthetic steps did not increase as compared to the known method because the hydrolysis of anthranylamide proceeded in an alkaline medium, in which the Schotten–Bauman acylation was carried out. The preparation of 2-benzoylamino-N-[4-(4,6-dimethylpyrimidin-2-ylsulfamoyl)phenyl]benzamide in the final step was modified by replacing the polar aprotic solvent DMF by the less toxic and more environmentally friendly DMSO. Use of more accessible and cost-effective starting materials in combination with Schotten–Bauman acylation, which eliminated environmentally hazardous benzene, was advisable for production of the active pharmaceutical ingredient. The developed laboratory procedure could be successfully used to obtain other biologically active compounds of o-benzoylaminobenzoic acid and their cyclic derivatives. [ABSTRACT FROM AUTHOR]

In this study, nano fibers were obtained from wheat bran, corn cob and sunflower receptacle by using micro-fluidization and then esterified with fatty acids (C6, C12, C18, C18:1) in different degrees of substitution. Firstly, cellulosic material was treated with NaOH and then milled through the colloid mill and micro-fluidizer to obtain nano-cellulose fiber. Cellulose, lignin and water holding capacity analyzes were made in these fiber. It was determined that as the cellulose content of the samples increased, their water holding capacity increased. These fibers were esterified with different fatty acids in different degrees of substitution to obtain nanocellulose-fatty acid esters. In this way, nanocellulose-fatty acid esters with different hydrophilic and lipophilic groups were obtained (degrees of substitution 0,41-2,99). Increasing the reaction time and increasing the amount of fatty acid used ensured that the esterification reaction took place at a high rate. Products with the maximum degree of esterification were obtained after 300 minute at 90°C with an average of 2.45 acetyl groups and 0.55 fatty substituents per anhydroglucose unit. As a result, cellulose was esterified with different fatty acids and acetic anhydride in DMAc/LiCl medium at different degrees. [ABSTRACT FROM AUTHOR]

A new series of pyrazolopyrazinoselenolotriazolopyrimidines was synthesized by a facile method based on condensation of 5‐amino‐3‐methyl‐1‐phenyl‐1H‐pyrazolo[3,4‐b]selenolo[3,2‐e]pyrazine‐6‐carbonitrile (3) with triethyl orthoformate followed by intramolecular cyclization with hydrazine to afford 7‐amino‐8‐imino‐3‐methyl‐1‐phenyl‐1,8‐dihydro‐7H‐pyrazolo[3″,4″:5′,6′]pyrazino[2′,3′:4,5] selenolo[3,2‐d]pyrimidine (5). The latter compound was utilized as a multipurpose precursor for the construction of other new triazoles fused to the pyrazolopyrazino‐ selenolopyrimidine moiety. Alternatively, acetylation and chloro‐acetylation of compound 3 using acetic anhydride and chloroacetyl chloride yielded the acetyl amino 11 and chloroacetamido 12 derivatives, respectively. Compound 12 underwent nucleophilic substitution upon reaction with morpholine to provide the morpholinyl acetamide 13. Furthermore, the pyrazolopyridoselenolopyrazine ring system 14 was synthesized by the reaction of the o‐amino‐carbonitrile 3 with malononitrile. Assignment of the chemical structures for the new compounds was confirmed depending on elemental and spectral techniques. On the other hand, most of the synthesized compounds revealed promising results against various bacterial and fungal strains. [ABSTRACT FROM AUTHOR]

An effective and direct synthetic strategy for a new series of functionalized mono-, bis-, and spiro[1,2,4]triazolo[1,5-a]pyridines from 1,2-diaminopyridine precursor has been described. Reaction of 1,2-diaminopyridine with ethyl orthoformate, acetic anhydride, maleic anhydride, carbon disulfide, or chloral hydrate under metal-free conditions afforded the desired triazolo[1,5-a]pyridine in good yield (62–76%). Furthermore, 1,2-diaminopyridine was converted to mono- and bis-[1,2,4]triazolo[1,5-a]pyridines via metal-free construction with decanoyl chloride, chloroacetyl chloride, terphthaloyl chloride, or diethyl succinate. Finally, spiro[[1,2,4]triazolo[1,5-a]pyridine and [1,2,4,3]triazaphospholo[1,5-a]pyridine derivatives were obtained via reaction of 1,2-diaminopyridine with cyclohexanone/pentanone in acetic acid or phosphorus pentasulfide in pyridine. This protocol aims to present some fundamental advances in the area of organic synthesis such as smart reaction conditions, improved yield, metal-free catalysts, no column purification, and no by-products, in addition to the broad functional scope. [ABSTRACT FROM AUTHOR]

A group of new substituted pyrimidine compounds, and their thiazolopyrimidines and 1,3,4-oxadiazolyl acyclic sugar derivatives have been synthesized as potential anti-cancer candidates. Oxadiazolyl-pyrimidine hybrid compounds have been synthesized by the reaction of thioacetohydrazide derivative with carbon disulfide and heterocyclization of sugar hydrazones with acetic anhydride. The synthesized products have been studied for their anticancer activity against human liver carcinoma (HepG-2) and human normal retina pigmented epithelium (RPE-1). The synthesized sugar hydrazine of D-glucose, its 1,3,4-oxadiazole acyclic nucleoside and arylidine derivative demonstrate high selective anti-cancer activity against liver cell line without side effects on normal cells. [ABSTRACT FROM AUTHOR]

2-Aminotetrahydro-4H-chromene-3-carbonitriles reacted with acetic anhydride in the presence of sulfuric acid to give isomeric substituted hexahydrochromeno[2,3-b]pyrimidin-4-ones in high yields. Pyridine ring fusion at the C3–C4 bond of the title compounds was accomplished by reacting 2-(2-amino-3-cyano-4H-chromen-4-yl)malononitrile with pyridin-2-amine under basic conditions. The products, substituted chromeno-[3,4-c]pyridinecarbonitriles, were found to exist as mixtures of amino and imino tautomers. The structure of the synthesized compounds and their isomer and tautomer ratios were determined by 1H and 13C NMR spectroscopy, including two-dimensional hetero- and homonuclear correlation experiments (1H–13C HMBC, 1H–13C HSQC, 1H–1H COSY). [ABSTRACT FROM AUTHOR]

A biodegradable poly(lactide) (PLA) plasticizer system derived from renewable feedstocks was deliberately designed with an ester structure identical to as many repeating units of the PLA matrix as possible for maximized compatibility, using two solvent-free one-pot synthetic routes, resulting in elastomeric performance as well as tunable plasticization. First, hydroxyl-ended lactide oligomers were precisely prepared with target molar mass values of 330–430 g mol−1 by controlled bulk ring opening oligomerization using 1-, 2-, and 3-arm initiators. They were subsequently esterificated with acetic anhydride to produce acetyl-terminated lactide oligomers (ALO) with enhanced thermal stability. Td,5% was increased by 23–43 °C and efficient biodegradation of 78–55% was achieved. The ALO series was added as plasticizers to PLA from 10 to 50 phr (9–33 wt%), and showed the ability to lower Tg,PLA to approximately 10–20 °C in DSC analysis and complete miscibility with PLA, as confirmed by visible or UV-vis transmittance, and SEM studies. The ALO had little contribution to changes in the PLA structure on SEC traces after the thermo-mixing process. The blends exhibited reasonable migration level, and controllable mechanical characteristics with ductile-to-elastomeric properties (E′ = 889–15 MPa, σy = 74–7 MPa, σb = 69–9 MPa, and εb = 13–658%), when compared to those of PLA. Interesting elastomeric behaviors were observed and then evidenced by stress relaxation moduli (2.4–9.8 MPa) and small residual strains (7–17%) after recovery tests, respectively. These results suggest that the ALO series can be practical "double green" and "dual performance" plasticizers for PLA. [ABSTRACT FROM AUTHOR]

The Friedel-Crafts acylation of furan to produce 2-acyl furan by using acetic anhydride is industrially important but it uses highly polluting liquid acids as catalysts. In this study, supported but modified heteropoly acids were used as heterogeneous catalysts in a solventless green process. Metal exchanged dodecatungstophosphoric acid (DTP) was loaded on three different supports, and its effect on acylation was evaluated. 20% w/w Chromium substituted DTP was supported on K-10 clay, SiO2, and ZrO2 using the incipient wetness impregnation method. Cr0.66-DK10 (dodecatungstophosphoric acid on K10) catalyst was found to have excellent activity for Friedel-Crafts acylation of furan. Under optimized condition, the catalyst to furan ratio was 9.6% which is significantly less as per prior art and it gave 88% conversion with 100% selectivity. The characterization of the synthesized catalyst was done using sophisticated techniques, namely, XRD, FT-IR, SEM, TEM, XPS, NH3-TPD, TGA, ICP/OES, and BET. The Eley-Rideal mechanism was used to fit the kinetic data. The apparent activation energy was 18.03 kcal/mol. The catalyst was robust and reusable. The reaction is green and clean because no chlorinated chemicals, reagents, solvent, and polluting catalysts were used. [ABSTRACT FROM AUTHOR]

Abstract Acetylation of softwoods has been largely investigated to increase the dimensional stability and biological resistance of wood. However, the knowledge of this technology has not been applied to tropical hardwood species up to date. The objective of this work was to study the effect of acetylation on nine tropical hardwood species, from forest plantations in Costa Rica, by applying acetic anhydride in three different treatment times (1 h, 2.5 h, 4 h), as well as to evaluate this by Fourier-Transform Infrared Spectroscopy (FTIR). Results showed that weight percentage gain (WPG) of wood varied from 2.2 to 16.8%, with Vochysia ferruginea species showing the highest WPG, and Gmelina arborea and Tectona grandis species exhibiting the lowest WPGs. Tropical woods such as Enterolobium cyclocarpum, Hieronyma alchorneoides and Samanea saman exhibited statistical differences among treatment times, whereas the rest of the species studied showed no significant differences. In general, the most effective acetylation time was 2.5 h for all the species. The ratio of intensity (RI) from the FTIR spectra was greater at the 1732 cm−1, 1372 cm−1 and 1228 cm−1 peaks for all tropical species, associated with lignin. A good correlation between the RI of those peaks and WPG was found; the same was also found between all RIs and each other. Meanwhile, RI associated to the hemicelluloses and lignin (1592 cm−1 and 1034 cm−1 peaks, respectively) showed no correlation with WPG, nor between each other or with the other RIs. Furthermore, it was suggested that RI at 1732 cm−1 (associated to acetyl groups C=O) can be considered as a reliable indicator of the degree of acetylation for tropical hardwood species. Finally, it was observed that tropical hardwoods having more suitable anatomical features, like larger vessel diameter, higher ray width and frequency, and lesser deposits such as gums and tyloses in the vessels, resulted in significantly higher WPGs.

A simple and efficient method for liquid-phase catalytic nitration of 1-nitronaphthalene with NO2 to 1,5-dinitronaphthalene under mild conditions has been developed. The results indicated that the sulfated zirconia (SO42−/ZrO2) as solid superacid catalyst exhibits superior catalytic performance with dioxygen and acetic anhydride. 93.8% conversion of 1-nitronaphthalene and 52.8% 1,5-dinitronaphthalene selectivity were achieved. Furthermore, the physicochemical properties of SO42−/ZrO2 were determined by XRD, Py-FT-IR, BET, FT-IR, Raman spectroscopy and ICP-OES technologies. The possible nitration reaction mechanism over SO42−/ZrO2 catalyst was proposed. The present work provides an easy-to-implement, mild and eco-friendly approach for the efficient preparation of valuable 1,5-dinitronaphthalene, which has extensive industrial application prospects. [ABSTRACT FROM AUTHOR]

The process of catalytic oxidation of toluene by ozone in the solution of a mixture «acetic anhydride-a strong acid» has been studied in the presence of compounds of transition metals. It is shown that the main oxidation products in the system Mn(Ac)2-(CH3CO)2O-H2SO4 at 20°C are benzylacetate and benzylidene diacetate with the yields of 39% and 29%, respectively. In the system CO(Ac)2-(CH3CO)2O-HA, the reaction is accompanied mainly by the formation of benzylidene diacetate (68.0%) and the yield of benzylacetate does not exceed 4.0%. The kinetic parameters of the main stages of the catalytic cycle were investigated. It was found that strong acids play a decisive role in increasing the activity of oxidized forms of the metal. Under the conditions of activation by strong acids, the reaction of methylbenzene with Me3+ occurs with a high degree of substrate conversion. It was found that the reduction of Me3+ in the reaction with the solvent becomes noticeable, along with the oxidation of toluene, with increasing the concentration of strong acids. It was stated that the selective oxidation of toluene under catalysis is initiated by the reaction with an oxidized form of the metal formed by the interaction of ozone with the catalyst. [ABSTRACT FROM AUTHOR]

Some of fused dihydrobenzo [4,5]imidazo [1,2-a] pyrmido [5,4-e] pyrmidin3(4H)-amine derivatives were synthesized, theses derivatives derived from 4- amino-2-(4-chloro or bromophenyl) -1,2-dihydropyrimido[1,2-a] benzimidazole3-carbonitrile (4 and 5), which prepared by reaction 1H-benzimidazol-2-amine (1) and p-chlorobenzaldehyde or p-bromobenzaldehyde (2) and malononitrile (3). These derivatives prepared by reaction compound (4 and 5) with with triethylorthoformate in presence acetic anhydride to give the products (6 and 7), then the products were reacted with aliphatic amines (hydrazine, methyl amine, ethyl amine, propyl amine and isobutyl amine) to give pyrimidine rings (8-17) respectively. All these derivatives characterization by FT-IR, 1HNMR spectra and physical properties. [ABSTRACT FROM AUTHOR]

Wood is an increasingly important material in the sustainable transition of societies worldwide. The performance of wood in structures is intimately tied to the presence of moisture in the material, which directly affects important characteristics such as dimensions and mechanical properties, and indirectly its susceptibility to fungal decomposition. By chemical modification, the durability of wood in outdoor environments can be improved by reducing the amount of moisture present. In this study, we refined a well-known chemical modification with acetic anhydride and showed how the spatial distribution of the modification of Norway spruce (Picea abies (L.) Karst.) could be controlled with the aim of altering the wood-water interactions differently in different parts of the wood structure. By controlling the reaction conditions of the acetylation it was possible to acetylate only the cell wall-lumen interface, or uniformly modify the whole cell wall to different degrees. The spatial distribution of the acetylation was visualised by confocal Raman microspectroscopy. The results showed that by this targeted acetylation procedure it was possible to independently alter the wood-water interactions in and outside of cell walls. The cell wall-lumen interface modification altered the interaction between the wood and the water in cell lumina without affecting the interaction with water in cell walls while the uniform modification affected both. This opens up a novel path for studying wood-water interactions in very moist environments and how moisture distribution within the wood affects its susceptibility towards fungal decomposition. [ABSTRACT FROM AUTHOR]

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

Pyrazolo [3,4-d]pyrimidin-4-amine are found most active molecules are synthesized by propanedinitrile, diethoxymethoxyethane and acetic anhydride and boiled at 180 degrees & yielded good products Ethoxy methylidene propanedinitrile which was then boiled and reacted with phenyl hydrazine and yielded 5-amino-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbonitrile and good percentile which then reacted with concentrated sulphuric acid and yielded 5-amino-1-phenyl-4,5-dihydro-1H-pyrazole-4-carboxamide and cyclysed with ester methyl chloro acetate and polymerised the pyrimidine ring the keto functional group on the molecules further chlorinated with phosphorous oxy chloride and yielded with good results 6-(chloromethyl)-1-phenyl-1,5-dihydro-4H-pyrazolo[3,4 -d]pyrimidin-4-one which further reacted with amines are substituted chlorines with amines groups. The antioxidant activity of the molecules was determined by free radical scavenging assay by in vitro method called DPPH assay. All the compounds (A1-A10) were found active in SOD assay procedure. In vivo anti oxidant activity evaluation of antioxidant activity using azathioprine induced oxidative stress in rats, superoxide dismutase: Superoxide dismutase is class of enzyme that catalyze the dismutation of superoxide into oxygen and hydrogen peroxide. It is an important antioxidant defence in nearly all cells exposed to oxygen. Superoxide dismutase activity was estimated in tissue homogenate with help of pure bovine superoxide dismutase standard and compounds A1was highly effective with anti oxidant activity. [ABSTRACT FROM AUTHOR]

Cascade catalysis allows multiple chemical steps to occur in a well-defined sequential manner without the isolation of reaction intermediates, and has been applied for the efficient preparation of natural products, pharmaceuticals and agrochemicals, with the preparation of organic functional dyes having been rarely explored. In the present study, light rare-earth elements are found to catalyse cascade reactions from simple aromatic substrates and acetic anhydride to give luminescent pyrylium salts with yields up to 50% under mild conditions. The cascade reactions have been coupled to supramolecular assembly to form aqueous pyrylium nanoparticles that can function as protein labels. [ABSTRACT FROM AUTHOR]

Herein, synthesis of a new series of pyrano[2,3-d]pyrimidine scaffolds is presented. Ethyl 6-amino-4-(4-chlorophenyl)-5-cyano-2-methyl-4H-pyran-3-carboxylate has been reacted with formamide, formic acid, urea, thiourea, semicarbazide, and thiosemicarbazide to give six new pyrano[2,3-d]pyrimidine derivatives in moderate to high yields (48–78%). Acylation and intramolecular cyclization of pyran with carbon disulfide, ethyl cyanoacetate, acetic anhydride, or chloroacetyl chloride has resulted in formation of the corresponding desired bicyclic pyrimidine derivatives. The chloromethyl derivative was subjected to nucleophilic substitution by its reaction with morpholine, piperidine or aniline resulting in the corresponding 2-substituted pyrimidine derivatives in good yields. [ABSTRACT FROM AUTHOR]

In continuation of our search for pharmacologically potent benzofuran compounds, we undertook the synthesis of 5- chloro-2-hydroxy benzonitrile (2) from 5-chloroslicylaldehyde (1) by treating with acetic anhydride and sodium ethoxide. We get biologically active benzofurans and their derivatives. When compound 2 was treated with chloroacetone, yielded compound 3. Then the compounds 4 and chalcones 5a-e were prepared by treating compound 3 with aqueous sodium hydroxide and substituted aldehyde, respectively. Compound 5a was converted into compound 6a by treating with acetic anhydride. All newly synthesized compounds have been characterized by IR, ¹HNMR, and Mass spectral data. All the extracts were screened for antimicrobial activities against various pathogenic microorganisms and exhibited appreciable activities compared with standard drugs. [ABSTRACT FROM AUTHOR]

Opening of the 1,6-anhydro bridge in levoglucosenone by the action of acetic anhydride in the presence of ZnCl2 afforded diastereoisomeric 1,6-di-O-acetyl-3,4-dideoxy-α/β-D-glycero-hex-3-enopyranos-2-uloses, and alcoholysis of the resulting diacetates in methanol, ethanol, and propan-2-ol in the presence of p-toluenesulfonic acid, camphor-10-sulfonic acid, ZnCl2, and HCl was studied. Their methanolysis in the presence of CSA gave methyl 3,4-dideoxy-α/β-D-glycero-hex-3-enopyranosid-2-uloses that are precursors to purpurosamine C and (+)-frontalin. [ABSTRACT FROM AUTHOR]

Cellulose acetate is one of the most important cellulose derivatives and commercially mainly produced using the Acetic Acid Process, in which overstoichiometric amounts of acetic anhydride and concentrated acetic acid are used to obtain cellulose triacetate. A subsequent partial hydrolysis is necessary to achieve evenly substituted cellulose acetates with lower degrees of substitution. Homogeneous acetylations in ionic liquids or other cellulose dissolving solvent systems often offer milder conditions and the possibility of a one-step synthesis of cellulose acetates with lower degrees of substitution by simply adjusting the equivalents of the acetylation agent. Here, we show an efficient homogeneous cellulose acetylation process without the need of any additional catalyst or activation step using the DBU/CO2 switchable solvent system. Vinyl acetate was used as a more benign acetylation agent under mild conditions and straightforward recyclability of all employed components was demonstrated with high recycling ratios (87.0–98.9%). Less cellulose backbone degradation compared to a cellulose acetate sample synthesized by the Acetic Acid Process from the same cellulose source was shown by size exclusion chromatography (Mn = 35 kDa vs. 12 kDa), which resulted in improved mechanical properties of solvent casted foils. Other homogeneous procedures reported so far (e.g. in ionic liquids) reached lower degrees of substitution, needed additional catalysts, proved to be less advantageous in terms of recycling, or required more reactive acetylation agents. Our results thus demonstrate a cellulose acetylation method with full focus on sustainability, efficiency, and applicability, resulting in an E-factor of 1.92 for the overall process. [ABSTRACT FROM AUTHOR]

An efficient and one-pot procedure is described for the synthesis of a variety of derivatives of 1,2-dihydrobenzo[f]chromen-3-ones and 3,4-dihydrochromen-2-ones under solvent-free conditions via a pseudo-four-component domino reaction of acetic anhydride, aryl aldehydes, glycine-based dithiocarbamates, and phenols/naphthols in the presence of l-proline and H4[Si(W3O10)4].xH2O as green catalysts. All products were made under the green strategy for the synthesis of corresponding products with excellent yields (up to 94%) and diastereoselectivity. [ABSTRACT FROM AUTHOR]

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

One of the main drawbacks which limit the utilisation of bamboos is its high moisture intake. To prevent excessive dimensional changes and improve moisture properties of bamboo, Bambusa vulgaris was chemically treated with acetic-anhydride without co-solvent. Weight gain (WPG), Bulking coefficient (BC), Rate of reaction (RR), Volumetric Swelling (VS) and Anti-swelling Efficiency (ASE) as well as changes in VS and ASE upon long term water soaking and weight loss to leaching (WL) were determined to evaluate the influence of acetylation on the moisture properties. The results indicated no significant effect of reaction temperature and time on the WPG, BC, VS and ASE of the acetylated bamboo while reaction time had significant influence on RR and WL. None of the acetylated bamboo samples had more than 3.67% WPG and 54.69% ASE. The maximum values of ASE of acetylated bamboo was 54.69% at 2.79 WPG, 100oC and 90 minutes while the lowest 13.08% was recorded at 2.89% WPG, 140oC and 30 mins reaction times. Reaction temperature had no influence on the initial and final volumetric swelling and final anti-swelling efficiency of the modified bamboo samples but reaction time had significant effect on initial ASE. Volumetric swelling of modified and unmodified samples increased from 8.47 to 18.58% and from 9.42% to 43.22% respectively within 7 days water soak period. Acetic anhydride form chemical bonds that were stable to solvent extraction in B. vulgaris. Acetylating at 120°C for 30 and 60 minutes is suitable for B. vulgaris to positively influence its sorption properties. [ABSTRACT FROM AUTHOR]

A systematic design and optimization method for vinyl acetate/acetic acid/acetic anhydride ternary system separation processes is proposed. Herein, four separation schemes including the conventional distillation, the inter‐column mechanical vapor recompression heat pump distillation (IMVRHP), the double mechanical vapor recompression heat pumps distillation (DMVRHPs), and DMVRHPs with heat exchange network (DMVRHPs‐HEN) are conducted. The optimal separation process is determined by minimizing the total annual cost (TAC) and CO2 emission. As a result, the three designed mechanical vapor recompression heat pump distillation (MVRHP) processes show better performance in all aspects than conventional distillation process. Specifically, the DMVRHPs‐HEN scheme saves 89.75% of the CO2 emission and 0.09% of the TAC compared with conventional distillation process. More important, the TACs of DMVRHPs‐HEN are decreased by 22.21% and 57.69% compared with those of conventional distillation process when the payback period is 5 and 8 years, respectively. This research is expected to provide theoretical guidance for the energy saving scheme of vinyl acetate/acetic acid/acetic anhydride ternary system. [ABSTRACT FROM AUTHOR]

The title ketenyl­idene, [Au3(C2O)(C26H35O2P)3](C2F6NO4S2), was obtained upon exposure of [2-(di­cyclo­hexyl­phosphino)-2′,6′-dimeth­oxy-1,1′-biphen­yl]gold(I) bis­(tri­fluoro­methane­sulfon­yl)imide to acetic anhydride at elevated temperature. The ketenyl­idene bridge caps the tri-gold cluster. The title compound has provided crystals that upon analysis represent the first tri-gold ketenyl­idene with atomic distances indicative of bonding inter­action between the gold atoms. [ABSTRACT FROM AUTHOR]

In response to the pressing demand for acetic anhydride gas detection, this study introduces a novel gas sensor for precisely detecting acetic anhydride concentrations. The optimum conditions for the synthesis of cobalt hydroxyfluoride/cobalt oxide (CHFCO) heterojunctions with good acetic anhydride gas sensitivity were determined by carefully adjusting the calcination time, hydrothermal time and ammonium fluoride content. The best performing composite CHFCO sensor with porous rod particles was tested at 180 ℃ and achieved a response rate of 260 for 100 ppm acetic anhydride gas, with response and recovery times of 60 and 40 s, respectively. In comparison to other prepared sensors, the detection response for acetic anhydride was improved by a factor of 4.30–23.63. Moreover, the CHFCO sensor reliably detected acetic anhydride at a concentration of 500 ppb, exhibiting a response value of 1.56. Notably, the sensor demonstrated great selectivity, moisture resistance, and stability. The findings highlight the significant enhancements in gas-sensitive performance to acetic anhydride achieved by the abundant hydroxyl bonds on the surface of CHFCO heterojunction, the presence of fluorine ions, and the modulation of the band gap. These results provide valuable insights for the advancement of acetic anhydride gas sensors based on CHFCO heterojunction. • Controlled synthesis of porous rod-like Co(OH)F/Co 3 O 4 heterojunction. • The sensor exhibits a high gas response of 260 at 180 °C for 100 ppm acetic anhydride. • The sensor has good selectivity and stability with detection limits as low as 500 ppb for acetic anhydride. • The combination of the catalytic activity of Co(OH)F and the adsorption properties of Co 3 O 4 produced a synergistic effect. [ABSTRACT FROM AUTHOR]

Oligonucleotide therapeutics are generally prepared via solid-phase synthesis, and many impurities derived from the synthesis process are present in crude oligonucleotides. Among the various impurities typical of oligonucleotide synthesis, shortmers, which lack a few residues from the desired oligonucleotide therapeutics, are difficult to remove using conventional high-performance liquid chromatography (HPLC) purification because they have similar structures and physical properties to the desired oligonucleotide. In this study, we developed a simple purification method for oligonucleotide therapeutics. In our strategy, the retention of shortmers on the reversed-phase HPLC column was increased by using a highly lipophilic phosphoramidite, which is a reagent for 5′-end modification of oligonucleotides, instead of acetic anhydride during solid-phase synthesis, and only the target oligonucleotide could be eluted from a reversed-phase HPLC pretreatment column. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to improve the properties of wood flour (WF)/poly(lactic acid) (PLA) 3D-printed composites, WF was treated with a silane coupling agent (KH550) and acetic anhydride (Ac2O), respectively. The effects of WF modification and the addition of acrylicester resin (ACR) as a toughening agent on the flowability of WF/PLA composite filament and the mechanical, thermal, dynamic mechanical thermal and water absorption properties of fused deposition modeling (FDM) 3D-printed WF/PLA specimens were investigated. The results indicated that the melt index (MI) of the specimens decreased after WF pretreatment or the addition of ACR, while the die swell ratio increased; KH550-modified WF/PLA had greater tensile strength, tensile modulus and impact strength, while Ac2O-modified WF/PLA had greater tensile modulus, flexural strength, flexural modulus and impact strength than unmodified WF/PLA; after the addition of ACR, all the strengths and moduli of WF/PLA could be improved; after WF pretreatment or the addition of ACR, the thermal decomposition temperature, storage modulus and glass transition temperature of WF/PLA were all increased, and water absorption was reduced.

Demand of clean water is always a major concern due to continuous use of toxic pesticides and herbicides to overcome food scarcity. In Asian countries, wide use of ionizable 2,4-D herbicide has worsen problem due to its less binding ability with soil and can easily contaminate drinking water that causes potential risks to humans and environment. The present research focused on synthesis of amino-factionalized coordination complexes using imidazole-based amino benzoic acid ligands for remediation of acidic 2,4-D herbicide. Coordination complexes characterized with FTIR, 1H-NMR, elemental analysis, thermogravimetric analysis, powder XRD, and BET revealed successful incorporation of functionalized groups with high thermal stability and surface area that make them suitable for adsorption experiments. Batch adsorption experiments conducted at different temperature conditions depicted the spontaneous physisorption process (− ∆G) having endothermic nature (∆H, ∆S). The removal efficiency of the amino-functionalized coordination complex is found to be higher (73%) compared to non-functionalized (35%) and acetic anhydride-functionalized coordination complex (42%). Kinetic studies supported pseudo 2nd-order kinetics with three phases of adsorption depicted by intra-particle diffusion model. Amino-functionalized complexes favored Langmuir isotherm while Freundlich isotherm is best fitted for non-functionalized complexes. The synthesized adsorbents were also proven to be effective for removal of herbicide from irrigated wastewater with average percent removal of 56% for amino functionalized, acetic anhydride functionalized (23%), and non-functionalized (20%). [ABSTRACT FROM AUTHOR]

Synthesis of ethyl 7-hydroxy-1-azacoumarin-3-carboxylate (3) was developed using ethyl-7-hydroxy coumarin-3-carboxylate and ammonium solution as the key synthons. Condensation of ethyl 7-hydroxy-1-azacoumarin-3-carboxylate with ammonium acetate and aniline to give N-substituted-7-hydroxy-1-azacoumarin-3-carboxamides (7-Hydroxy -1-azacoumarin-3-carboxamide (4) and N-phenyl 7-Hydroxy-1-azacoumarin-3-carboxamide (5)). Bromo derivative (N-phenyl 6, 8-dibromo-7-hydroxy-1-azacoumarin-3-carboxamide (6)) was obtained from halogenation of compound N-phenyl 7-Hydroxy-1-azacoumarin-3-carboxamide (5) with bromine in glacial acetic acid. N-phenyl-2,5-diacetoxy-6, 8-disubstituted-Quinoline-3-carboxamides (N-phenyl 2,7-diacetoxy-Quinoline-3-carboxamide (7) and N-phenyl 2,7-diacetoxy-6,8-dibromo-Quinoline-3-carboxamide (8)) were prepared via the acetylation of compounds 5 and 6 with acetic anhydride. Five compounds 4–8 were evaluated in vitro against more than one human tumor cell lines. Among the selected compounds, 6 showed the best in vitro cytotoxicity against the human cancer cell line; MCF-7 (with IC50 = 10.12 μM). In addition, cell cycle analysis of compound 6 demonstrated cell cycle arrest at G2/M phase and Pre-G1 apoptosis. [ABSTRACT FROM AUTHOR]

BACKGROUND Applications of chemical and enzymatic methods of esterification have been limited by low selectivity of chemical catalysts and low productivity and high cost of enzymes. The objective of this study was to produce eugenol esters with high productivity and selectivity using a microwave technique without adding any catalyst or solvent. Specific focus was given to reaction temperature and molar ratio to establish the kinetics and mechanism of eugenol auto‐catalytic acylation using microwave radiation. RESULTS: Reaction conversion was observed to increase in response to higher temperatures. The optimum molar ratio of eugenyl/acetic anhydride was 1:6, while the optimum molar ratio of eugenyl/butyric anhydride was 1:4.5. A high degree of selectivity (of over 97%) occurred under all conditions of the reaction. Based on modelling studies, it can be concluded that the intended reaction follows second‐order kinetics for both eugenyl acetate and eugenyl butyrate. Microwave heating at 70 °C led to an increase of rate constant by 3.71‐ and 3.83‐fold for eugenyl acetate and eugenyl butyrate, respectively, as compared to the conventional method. This was associated with a decrease in the activation energy (4.38% for eugenyl acetate and 3.11% for eugenyl butyrate) and an increase in the frequency factor (42.31% for eugenyl acetate and 49.84% for eugenyl butyrate) and entropy (4.71% for eugenyl acetate and 5.22% for eugenyl butyrate) as a result of using microwave radiation. CONCLUSIONS: The microwave technique can be considered as a green, low‐cost and quick process for auto‐catalytic production of eugenol esters. © 2020 Society of Chemical Industry (SCI) [ABSTRACT FROM AUTHOR]

Several non‐hydrolytic sol–gel syntheses involving different precursors, oxygen donors, and conditions have been screened aiming to selectively produce mesoporous t‐ZrO2 or m‐ZrO2 with significant specific surface areas. The in situ water formation was systematically investigated by Karl Fisher titration of the syneresis liquids. XRD and nitrogen physisorption were employed to characterize the structure and texture of the ZrO2 samples. Significant amounts of water were found in several cases, notably in the reactions of Zr(OnPr)4 with ketones (acetone, 2‐pentanone, acetophenone), and of ZrCl4 with alcohols (benzyl alcohol, ethanol) or acetone. Conversely, the reactions of Zr(OnPr)4 with acetic anhydride or benzyl alcohol at moderate temperature (200 °C) and of ZrCl4 with diisopropyl ether appear strictly non‐hydrolytic. Although reaction time and reaction temperature were also important parameters, the presence of water played a crucial role on the structure of the final zirconia: t‐ZrO2 is favored in strictly non‐hydrolytic routes, while m‐ZrO2 is favored in the presence of significant amounts of water. 1H and 13C NMR analysis of the syneresis liquids allowed us to identify the main reactions responsible for the formation of water and of the oxide network. The morphology of the most interesting ZrO2 samples was further investigated by electron microscopy (SEM, TEM). [ABSTRACT FROM AUTHOR]

• New data of kinetics of hydrolysis of acetic anhydride. • Effects of strong-acid catalyst and inhibitory effects of salts studied and modeled. • Isoperibolic calorimetric technique very simple and reliable. • Kinetic parameters determined and compared with the literature • Good agreement with experimental data. The effect of strong acid (hydrochloric acid) catalyst and salts (sodium chloride and potassium chloride) on the kinetics of the hydrolysis of acetic anhydride was studied using a simple isoperibolic calorimetric technique. The apparent second-order rate constant was observed to increase linearly with the increase in the strong acid concentration, suggesting the occurrence of a non-catalytic and an acid-catalyzed reaction route. The kinetic parameters for the non-catalytic route and for the acid-catalyzed route were determined. The effect of salt concentration causes a decrease in the effective rate constant over the range of variables studied. Sodium and potassium chloride presented practically the same negative effect on the hydrolysis kinetics. [ABSTRACT FROM AUTHOR]

A novel and facile synthesis of Iclaprim was reported. Started from trimethoprim (TMP), the amino-protection and Friedel–Crafts acetylation with acetic anhydride were simultaneously completed in CH2Cl2 with SnCl4 as catalyst. The Knoevenagel condensation of 2,4-diamino-5-(2-acetyl-3-hydroxy-4,5-dimethoxybenzyl)pyrimidine with cyclopropyl carboxaldehyde followed by the intramolecular Michael addition in the buffer system (pyrrolidine and acetic acid) installed the key framework (chromanone 13). The dehydration was catalyzed by H2SO4 so that the formation of 5-cyclopropyl-2,3-dimethoxy-4,5,6,6a,7,12-hexahydronaphtho[1,8-bc]pyrimido[5,4-f]azepin-9-amine, an impurity of Iclaprim reported at the first time, could be minimized. In the end, Iclaprim was obtained in a total yield of 21%. [ABSTRACT FROM AUTHOR]

Acetylated cellulose nanocrystals (ACNC) were prepared by surface modifying cellulose nanocrystals (CNC) with acetic anhydride (AA). By adding ACNC into biodegradable poly(butylene succinate-co-butylene adipate) (PBSA), ACNC/PBSA composites were prepared via a melt blending method. The structure and morphology of the ACNC were analyzed by Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction (WAXD) analysis, field emission scanning electron microscopy (FE-SEM) and contact angle measurements. The results showed that the CNC were successfully modified by acetic anhydride, while maintaining their original nanosize rod shape of CNC and showing obvious hydrophobicity. SEM images of the ACNC/PBSA composites indicated that the ACNC were homogeneously dispersed in the composites. With increasing ACNC content, the crystalinity, melt viscosity and decomposition starting temperature increased gradually. In addition, the tensile strength of the ACNC/PBSA composites showed a maximum value at a ACNC content of 3.0%, which was 26.3% higher than for pristine PBSA but the elongation at break was 20% lower than for pristine PBSA. [ABSTRACT FROM AUTHOR]

There is an increasing interest in substituting current packaging films with biologically-derived films without compromising mechanical properties and hydrophobicity. In this work, the esterified galactomannan (E -GM) films with good hydrophobicity, excellent oxygen barrier performance and high tensile mechanical strength were synthesized using anhydride esterification method prior to film formation. The hydrophobicity, mechanical properties, barrier properties, thermal stability and ultraviolet absorption of the prepared films were determined to fully investigate the features of galactomannan-based films. The results indicated that GM films can be successfully obtained by esterification. Compared to neat GM film, E -GM-1.5 film (acetic anhydride to GM of 1.5:1) achieved the highest degree of esterification (0.05), hydrophobicity (107°) and mechanical strength (92.0 MPa). In addition, the esterified GM films had lower toxicity for macrophages cells. The prepared E-GM films may provide more opportunities for further advancement and applications in the development of food packaging from natural resources. [ABSTRACT FROM AUTHOR]

The effect of phosphorus-containing catalysts, namely phosphorous acid, phosphoric acid, diethyl hydrogen phosphite, and 1-hydroxyethane-1,1-diyldiphosphonic acid (HEDP), in the synthesis of tetraacetylglycoluril by acylation of glycoluril with acetic anhydride at 140°C has been studied. The use of 4 equiv of phosphorous or phosphoric acid with respect to glycoluril has been found to be the most appropriate for achieving the maximum yield (95–98%), and specific effect of HEDP leads to N-acetylation–deacetylation of substrates. The positive effect of phosphorus acids on the formation of tetraacetylglycoluril may be related to not only their catalytic action but also the ability to solubilize the substrate. [ABSTRACT FROM AUTHOR]

(Benzimidazol-2-yl)-7-hydroxycoumarin and N-(2-hydroxyphenyl)-7-hydroxycoumarin-3-carboxamide have been synthesized by the condensation of ethyl 7-hydroxycoumarin-3-carboxylate in acetic acid. Acetylation with acetic anhydride and halogenation with bromine in acetic acid's presence of the previous compounds has yielded the corresponding acetoxy and dibromo derivatives. The synthesized molecules that contain coumarin ring have been evaluated for their activities against breast cancer and they have shown good in vitro antiproliferative activities against a human breast cancer line (MCF-7). The results have shown that 3-(benzimidazol-2-yl)-7-acetoxycoumarin had a significant cytotoxic effect compared to the standard DOX (doxorubicin) drug. [ABSTRACT FROM AUTHOR]

6-O-Acetylated derivatives of D-hexopyranosides are valuable intermediates in synthetic carbohydrate chemistry. We have developed a new simple procedure for selective acetylation of the primary hydroxyl group in methyl D-hexopyranosides consisting in treatment with a mixture of acetic anhydride and acetic acid at 50°C. As a result, corresponding 6-acetates were formed in 40–50% yield. [ABSTRACT FROM AUTHOR]

Cyclin-dependent kinase 2 (CDK2) is a critical protein kinase entangled in the cell cycle regulation. The irregular activity of CDK2 is correlating with cancer development and metastasis. Here structural resemblance of pyrazolopyrimidines to purines prompted the investigation of their chemical significance and their anticancer activity. Several new pyrazolopyrimidine compounds were obtained from 5-amino-3-(cyanomethyl)-1H-pyrazole-4-carbonitrile 1, which was initially reacted with acetic anhydride at refluxed to form 2-(4-imino-6-methyl-1,4-dihydropyrazolo[3,4-d][1,3]oxazin-3-yl)acetonitrile 2 and N-(4-cyano-3-(cyano methyl)-1H-pyrazole-5-yl)acetamide 3. The affinity of compound 2 towards nucleophiles was studied by its reaction with various primary aromatic amines to furnish the newly pyrazolo[3,4-d] pyrimidines 4a-c. The reaction of 2-(4-imino-6-methyl-1,4-dihydropyrazolo[3,4-d][1,3]oxazin-3-yl) acetonitrile 2 with hydrazine hydrate gave pyrazolopyrimidine 5 which condensed with aromatic aldehydes to form pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives 6a-d. All possible tautomers of 2-(4-imino-6-methyl-1,4-dihydropyrazolo[3,4-d][1,3]oxazin-3-yl) acetonitrile 2 were studied by DFT (density functional theory) and the constancy of compounds 4 over compounds 3 was discussed and established by quantum mechanics. [ABSTRACT FROM AUTHOR]