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International Symposium "The Environment and the Industry", 26-27 September 2019, Bucharest, Romania, pp. 89-90

A simple and efficient method for the synthesis of 3-oxopropanenitriles from variously substituted heterocyclic compounds via direct electrophilic cyanoacetylation is described. A series of heterocyclic 3-oxopropanenitriles (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k) have been synthesized using mixed anhydride (acetic or trifluoroacetic anhydride:cyanoacetic acid) in the presence of Mg(ClO4)2·2H2O as catalyst. This method can be extended also for the cyanoacetylation of electron poor aromatic compounds.

Methods for generating tert-alkyl organoboron species are in high demand as they are invaluable intermediates for the synthesis of quaternary carbon centres. Herein we report investigations into generation of tert-alkyl organoboron species using imidoyl chlorides as reagents in the organoboron cyanidation reaction. Although alkenyl side-products predominate in particularly hindered cases, tert-alkyl organoboron species can be successfully generated for less hindered examples.

This study describes a simple, efficient, and environmentally benign procedure for synthesizing a novel series of 13 N-(pyrimidinyl)-N-(1H-benzo[d]imidazolyl)amines, from the cyclocondensation reaction of (benzo[d]imidazolyl)guanidine with 4-alkoxy-4-alkyl(aryl/heteroaryl)-1,1,1-trifluoroalk-3-en-2-ones or 2,2,2-trifluoro-1-(2-methoxycyclohexen-1-en-1-yl)ethanone. The (benzo[d]imidazolyl)guanidine precursor was earlier obtained from the reactions of cyanoguanidine with o-phenylenediamine. The trifluoroacetylated enol ethers were synthesized from the trifluoroacetylation reaction of enol ethers or acetals with trifluoroacetic anhydride. The main reactions were performed in pure refluxing water as the solvent (1–24 h), without catalysts, and the corresponding new N-(pyrimidinyl)-N-(1H-benzo[d]imidazolyl)amines were obtained at good to excellent yields (60–90 %). Subsequently, N-alkylation reactions were performed to obtain tertiary amines and to increase the solubility of the amines.

Three compounds 1-3 containing methyl-sufanyl, sufinyl, or sulfonyl groups are strong inhibitors of glycogen synthase kinase 3β (GSK-3β), an enzyme associated with Alzheimer's disease. We labeled 1-3 with (11)C for a positron emission tomography (PET) brain imaging study. A novel thiophenol precursor 4 for radiosynthesis was prepared by reacting sulfoxide 2 with trifluoroacetic anhydride. [(11)C]1 was synthesized by reacting 4 with [(11)C]methyl iodide in 52 ± 5% radiochemical yield (n = 5, based on [(11)C]CO2, corrected for decay). Oxidation of [(11)C]1 with Oxone® produced [(11)C]2 and [(11)C]3, respectively. PET with [(11)C]1 and [(11)C]3 showed 2 fold higher brain uptake of radioactivity in a mouse model of cold water stress in which GSK-3β expression was increased, than in the controls.

Electron-rich thiophenes were trifluoroacetylated by trifluoroacetic anhydride with different nitrogen bases in dichloromethane at room temperature in good yields. Trifluoroacetylation without a base gave significantly lower yields. Trifluoroacetylation of electron-rich thiophenes

Intramolecular Friedel–Crafts acylation reactions of 2-arylphenoxyacetic acids are accomplished using trifluoroacetic anhydride or trifluoromethanesulfonic acid at 0 °C or room temperature. Depending on the reaction conditions, dibenzoxepines or arylcoumaranones are obtained in good yields and with high selectivities (83–100%). Plausible mechanistic pathways for the selective formation of the different reaction products are discussed.

Fully substituted pullulan (PL) esters with carbon number of acyl group (n) of 2–14 were prepared in carboxylic acid/trifluoroacetic anhydride (TFAA) system. Thermal properties of PL esters were analyzed by differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). The decomposition temperatures of the PL esters were higher than that of neat PL. DSC measurements revealed that the PL esters did not exhibit melting peaks, indicating that PL esters were amorphous. The glass transition temperatures (Tgs) of PL esters increased from 35 °C for PL myristate (PLMy, n = 14) to 174 °C for PL acetate (PLAc, n = 2) as the chain length decreased. WAXD diffractogram of the PL esters showed the reflection at small-angle region, indicating alignment of the PL main-chain caused by side-chains which are extended perpendicular to the main-chain. Colorless and transparent PL ester films were obtained by solvent casting and melt-pressing method. DMA analyses indicated a β-relaxation of alkyl side-chains below room temperature. Tensile strength of the PL ester films decreased with increase in alkyl carbons from 23.4 MPa for PLAc to 1.4 MPa for PLMy. The elongation at break of the PL esters increased with increase in alkyl carbons from 8% for PLAc to 1090% for PLMy. The PL esters exhibited extremely high elongation at break. PL esters could be electrospun into nanofibers.

Mixed paramylon esters prepared from paramylon (a storage polysaccharide of Euglena), acetic acid, and a long-chain fatty acid by one-pot synthesis using trifluoroacetic anhydride as a promoter and solvent were shown to have thermoplasticity. Size exclusion chromatography indicated that the mixed paramylon esters had a weight average molecular weight of approximately 4.9-6.7×10(5). Thermal analysis showed that these esters were stable in terms of the glass transition temperature (>90°C) and 5% weight loss temperature (>320°C). The degree of substitution of the long alkyl chain group, a dominant factor determining thermoplasticity, was controlled by tuning the feed molar ratio of acetic acid and long-chain fatty acid to paramylon. These results implied that the one-pot synthesis is useful for preparing structurally-well defined thermoplastic mixed paramylon esters with high molecular weight.

One hundred and fifty nanometre thick polymer films made of allyl alcohol and H2O addition were deposited onto aluminium substrates using the radio-frequency (rf) pulsed plasma mode. The structure–property relationships of polymer films were studied in dependence on the precursor ratio allyl alcohol-water. Both the regularity of structure and composition of such thin films in comparison to chemically polymerized allyl alcohol were investigated using by bulk-sensitive Fourier transform infrared spectroscopy (FTIR) in the spectral range of 4000–500 cm−1 as well as surface-sensitive X-ray photoelectron spectroscopy (XPS). The intention of this work was to increase the yield in OH groups by addition of water to the allyl alcohol precursor. For an unambiguous identification of the functionality of the deposited films, the OH groups were labelled with trifluoroacetic anhydride and subsequently measured by XPS as well as quantitatively by FTIR. As expected, the O/C ratio grew with increasing water admixture by o...

Synthetic cannabinoids, including JWH-018 and JWH-073, belong to a class of aminoalkylindoles (AAIs) that are smoked to produce an effect similar to tetrahydrocannabinol. Compounds in this class are often collectively known as 'Spice'. After ingestion, these compounds are extensively metabolized to their hydroxy and carboxylic acid metabolites. During forensic analysis, detection of these metabolites in urine is an indication of past exposure to the parent compounds. The analytical process involved hydrolysis of conjugated metabolites by glucuronidase, solvent extraction, derivatization by trifluoroacetic anhydride and hexafluoroisopropanol and GC-EIMS detection. Identification of the unknown was based on the criteria of GC retention time within ±2% and mass spectral ion ratio within ±20% of that of a standard. Deuterated internal standards of the carboxylic acid metabolites were used for quantification. The acid (JWH-018-COOH, JWH-073-COOH) and hydroxy (JWH-018-OH, JWH-073-OH) metabolites were linear over the concentration range of 0.1-10 and 0.2-10 ng/mL, respectively, with a correlation coefficient-square, R(2) > 0.999 (N = 5). Extraction recoveries of the metabolites were within 79 and 87%. The method was applied to 17 urine specimens collected as part of a military law enforcement investigation. Nine of the specimens tested positive for one or more of the metabolites. When the procedure was extended to screen other AAI compounds, two of the specimens were found to contain JWH-210, JWH-250 (JWH-302 or JWH-201) and JWH-250 (C4 isomers). The GC-EIMS method presented here was found to be suitable for detecting JWH-018 and JWH-073 metabolites and other AAI compounds in urine.

A practical method to prepare enantiopure 4,4,4-trifluoro-allo-threonine was developed by using an easily available fluorinated building block and a chiral auxiliary as starting materials. Trifluoroacetic anhydride was annulated with a ketene, derived from a glycine equivalent bearing a chiral oxazolidinone [(4S,5R)-4,5-diphenyloxazolidin-2-one], and acetone to afford a trifluoromethylated α,β-unsaturated lactone. The asymmetric hydride reduction of the α,β-unsaturated lactone proceeded with excellent stereoselectivity to give the corresponding (2R,3S)-4-oxapentan-5-olide derivative exclusively (diastereopurity, 99%). From the reduced product thus obtained, protecting groups were readily removed by acid treatment and subsequent catalytic hydrogenolysis to afford enantiopure (2R,3S)-4,4,4-trifluoro-allo-threonine in an excellent yield (7 steps, 51% overall yield).

A novel, selective acylation of primary phenylalkyl amines (PPAAs) using hexamethyldisilazane (HMDS) and perfluorocarboxylic acids (PFCAs) is noted. Couples, like HMDS and trifluoroacetic acid, HMDS and pentafluoropropionic acid, or HMDS and heptafluorobutyric acid trigger PPAAs’ quantitative acylation. Processes’ selectivity was characterized by applying all couples to derivatize benzyl, 2-phenylethyl, 3-phenylpropyl, 4-phenylbutyl amines, and their relevant substituted versions. Aliphatic amines were unreactive. Identification, quantification, proportionality, and stoichiometry in derivatization processes were determined by gas chromatography/mass spectrometry. Reaction conditions were optimized depending on reagents’ molar ratios, solvents, and temperatures applied. The new acylation method, in comparison to the traditional ones, obtained with trifluoroacetic anhydride, heptafluorobutyric anhydride, and N-methyl-bis(trifluoroacetamide), offers numerous advantages. Derivatives, provided by couples, can be directly injected onto the column, avoiding loss of species, saving time, work, and cost in the preparation process. Due to traditional reagents’ excess evaporation by nitrogen drying, the loss of trifluoroacylated species proved to be 65% or less. Regarding heptafluorobutyryl species, their losses varied between 25% and 5%. Unified huge responses, obtained with the HMDS and PFCA couples are attributable to their direct injection onto the column and to fragments sourced from the molecular ions and from their self-chemical ionization ([M]•+, [M+147]+, i.e., [M+(CH3)2–Si═O–Si–(CH3)3]+). The reaction mechanism, due to the HMDS symmetrical structure, acting HMDS as acylation generator for PFCAs, was confirmed by density functional theory (DFT) computation.

A series of fully-acylated dextrin esters (DS = 3) with varying side-chain lengths (C2–12) were synthesized by heterogeneous esterification using trifluoroacetic anhydride/carboxylic acid. The influence of side-chain lengths on structure and properties of dextrin esters were investigated by structural, thermal, mechanical and hydrophobic analysis. The thermal stability of dextrin was enhanced by esterification, presenting ca. 40–60 °C higher decomposition temperatures than that of neat-dextrin. The transition temperatures of melting and crystallization were not observed for all dextrin esters because they were amorphous polymers. The glass transition temperature (Tg) was not observed in dextrin but was observed in dextrin esters. As increasing side-chain length, Tgs of dextrin esters decreased ranged from 162.2 °C (C2) to 49.2 °C (C12). Colorless and transparent dextrin ester films were prepared to measure the film properties. Tensile strength of dextrin ester films tended to decrease with increasing side-chain lengths, whereas the elongation at break increased. And, dextrin ester films showed significantly increased hydrophobicity with a contact angle of up to 102° (C12).

Widening the methodology of chromophore analysis in pulp and paper science, a sensitive gas-chromatographic approach with electron-capture detection is presented and applied to model samples and real-world historic paper material. Trifluoroacetic anhydride was used for derivatization of the chromophore target compounds. The derivative formation was confirmed by NMR and accurate mass analysis. The method successfully detects and quantifies hydroxyquinones which are key chromophores in cellulosic matrices. The analytical figures of merit appeared to be in an acceptable range with an LOD down to approx. 60 ng/g for each key chromophore, which allows for their successful detection in historic sample material.

Achieving an energetic compound, which exhibits high performance and insensitivity, is important in the field of energetic materials and remains a major challenge. Herein, we found that oxidation of 4,7-diaminopyridazino[4,5-c]furoxan (5) with a mixture of 50 % hydrogen peroxide and trifluoroacetic anhydride gave 6-amino-7-nitro-[1,2,5]oxadiazolo[3,4-c]pyridazine (7) and its N-oxide derivative (8). The oxidation of 5 with hypofluorous acid (HOF) was also studied. Compound 8 displayed an energetic performance compared to triaminotrinitrobenzene (TATB) and insensitive properties (impact sensitivity (IS) 36 J and friction sensitivity (FS)360 N). Such excellent properties make 8 attractive for high-performance applications, in which insensitivity is important.

The heptafluorobutyric anhydride (HFBA), pentafluoropropionic anhydride (PFPA), and trifluoroacetic anhydride (TFAA) are compared as derivatizing reagents to use as the optimal method for the analysis of 10 amphetamines and cathinones in oral fluid. The target compounds were amphetamine (AMP), methamphetamine (MA), 4-methylamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxy- N-ethylamphetamine (MDEA), cathinone (CAT), methcathinone, mephedrone, and ephedrine. Amphetamine-D5, MA-D5, MDA-D5, MDMA-D5, and MDEA-D5 use as internal standards (IS). The analytes and IS were extracted from 0.5 mL of oral fluid by ethyl acetate in the presence of NaOH (0.1 N) as the base and then the dried extracts were derivatized with HFBA, PFPA, or TFAA at 70°C for 30 minutes. The limits of quantification based on signal-to-noise ratios ≥10 were ranged between 2.5 and 10 ng/mL. The calibration graphs were linear in the range of 5 or 10 to 1000 ng/mL for all analytes. Based on sensitivity, the PFPA is proved to be the best for derivatization of the target compounds prior to gas chromatography-mass spectrometry analysis.

A series of novel N-((2,5-diaryl-3-trifluoroacetyl)-1H-indol-7-yl)acetamides has been prepared via a successive and one-pot reaction sequence involving initial trifluoroacetic acid-mediated Beckmann rearrangement of the oximes derived from the 1-(2,5-diaryl-1H-indol-7-yl)ethanones, followed by trifluoroacetylation of the incipient N-(2,5-diaryl-1H-indol-7-yl)-acetamides with trifluoroacetic anhydride. The prepared compounds were evaluated for potential in vitro antiplasmodial properties. Preliminary results from antiplasmodial activity against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum revealed that a combination of 2-(4-flurophenyl)- and 5-(4-fluorophenyl) or 2-(4-flurophenyl)- and 4-fluorostyryl groups in compounds 3(a,f) and 4(a,g), for example, is required for biological activity for both series of compounds. Their possible mode of action against the plasmodial parasite is explained theoretically through molecular docking of the most active compounds against the parasite lactate dehydrogenase (pLDH). These compounds were docked at the entrance of NAD+ in pLDH presumably hindering entry of lactate to cause the observed inhibition effect of pLDH. The four compounds were found to exhibit low toxicity against monkey kidney Vero cells at the highest concentrations tested.

A copper(I)-catalyzed interrupted click reaction in the presence of trifluoroacetic anhydride has been developed, wherein an N-trifluoroacetyl group is used to accelerate the ring-opening of the putative 5-copper(I) triazolide intermediate. Under the optimized reaction conditions, a broad range of azides and alkynes were found to participate in this transformation, thus affording 3-trifluoromethyl-substituted 1,2,4-triazinones in moderate to excellent yields. The reaction has proven to be compatible with a variety of electron-withdrawing and electron-donating groups, halogens, and nitrogen- and sulfur-containing heterocycles, as well as pharmaceutically relevant molecules.

Six acylation reagents have been compared for their derivatisation potential towards nine synthetic cathinones by gas chromatography-mass spectrometry (GC-MS). The evaluated reagents were pentafluoropropionic anhydride (PFPA), trifluoroacetic anhydride (TFA), chlorodifluoroacetic anhydride (CLF2AA), heptafluorobutyric anhydride (HFBA), acetic anhydride (AA) and propionic anhydride (PA). The synthetic cathinones included flephedrone (4-fluoromethcathinone or 4-FMC), mephedrone (4-methylmethcathinone or 4-MMC), pentedrone (also known as α-methylamino-valerophenone), methedrone (4-methoxy-N-methcathinone, p-methoxymethcathinone), methylone (3,4-methylenedioxy-N-methylcathinone or bk-MDMA), butylone (β-keto-N-methylbenzodioxolylbutanamine or bk-MBDB), ethylone (3,4-methylenedioxy-N-ethylcathinone MDEC or bk-MDEA), pyrovalerone (4-methyl-β-keto-prolintane) and 3,4-methylenedioxypyrovalerone (MDPV). The derivatizing agents were optimised for incubation time and temperature with some important validation parameters studied to evaluate derivatisation reactions. The anhydrides studied proved to be suitable for synthetic cathinones – all of them showing RSD and accuracy below 20%. PFPA and HFBA followed by TFA are the best choice of derivatising agents based on validation parameters. Five internal standards were evaluated with good results. Three way ANOVA, interference, fragmentation patterns and high peak area values at a concentration of 0.50 μg ml−1 were evaluated and discussed. AA and PA derivatives give high relative abundance for most drugs examined. HFBA gives more ions and multi-fragmentation patterns.

Highly stable, pure, and anhydrous organometallic YBa2Cu3O7- (YBCO) precursor solutions were prepared by dissolving commercial YBCO powder in acetone by trifluoroacetic anhydride (TFAA) or a mixture of TFAA with propionic acid for low fluorine precursors. It is shown that compared to conventional oil bath heating reported in literature, the reaction to produce YBCO precursor occurs 72 times faster by microwave heating. More importantly, the formation of byproducts is suppressed, as shown by nuclear magnetic resonance (NMR) and mass spectrometry (MS). This approach allows a highly reproducible preparation of superconducting coatings which is of interest for low-cost manufacturing processes capable of large-scale production of the coated conductors via chemical solution deposition (CSD). This technology requires reliable and stable precursor solutions for continuous deposition. In this work, we obtained YBCO thin films on single-crystal substrates ((100)-LaAlO3) with a high critical current density (J(c)) of 3-4 MA/cm(2) in self-field at 77 K using TFA-based YBCO precursors and J(c) of 5-6 MA/cm(2) using low fluorine YBCO precursors.

We report here the direct formation of the new chemical product trans-2,5-dihydroxy-3-pentenoic acid methyl ester from pentoses using tin-containing silicates as catalysts. The product is formed under alkali-free conditions in methanol at temperatures in the range 140–180 °C. The highest yields are found using Sn-Beta as the catalyst. Under optimised conditions, a yield of 33% is achieved. Purified trans-2,5-dihydroxy-3-pentenoic acid methyl ester was used for co-polymerisation studies with ethyl 6-hydroxyhexanoate using Candida antarctica lipase B as the catalyst. The co-polymerisation yields a product containing functional groups originating from trans-2,5-dihydroxy-3-pentenoic acid methyl ester in the polyester backbone. The reactivity of the incorporated olefin and hydroxyl moieties was investigated using trifluoroacetic anhydride and thiol–ene chemistry, thus illustrating the potential for functionalising the new co-polymers.

Levulinate is an important hydroxyl protecting group in carbohydrate chemistry but has not previously been so employed in cellulose chemistry, perhaps because of challenges involved in synthesis of cellulose levulinates. Herein we describe homogeneous acylation of cellulose in N,N-dimethylacetamide/LiCl using differently activated levulinic acid derivatives, including in situ activation with dicyclohexylcarbodiimide, p-toluenesulfonyl chloride, 1,1′-carbonyldiimidazole, or trifluoroacetic anhydride, providing and comparing several methods to access cellulose levulinates. Degree of substitution (DS) has been determined by 1H NMR spectroscopy using perpropionylated cellulose levulinates, showing that DS values as high as 2.42 are attainable. Cellulose levulinate esters were deacylated selectively by hydrazine without detectable loss of other alkanoate ester groups (acetate or propionate), indicating strong promise for levulinate as a useful protecting group for the synthesis of regioselectively substituted cellulose and other polysaccharide derivatives.

5-Trifluoroacetylpyrrole-2-carbaldehydes were synthesized by low-temperature trifluoroacetylation of pyrrole-2-carbaldehyde acetals using trifluoroacetic anhydride, with subsequent removal of the acetal protecting group by mild acid-catalysed hydrolysis. The hydrolysis was accompanied by the formation of a minor product, (1Е,4Е)-1,5-bis[5-(2,2,2-trifluoroacetyl)-1Н-pyrrol-2-yl]-1,4-pentadien-3-one, which was isolated and identified.

Dihydrogen tetrametaphosphate [P4O12H2](2-) (1) can now be synthesized and isolated as its PPN salt ([PPN](+) = [N(PPh3)2](+)) via treatment of [PPN]4[P4O12] with trifluoroacetic anhydride in wet acetone; this simple procedure affords the oxoacid salt in 94% yield. A pKa of 15.83 ± 0.11 in acetonitrile was determined. [P4O12H2](2-) reacts with the dehydrating agent N,N'-dicyclohexylcarbodiimide to afford tetrametaphosphate anhydride [P4O11](2-) (2) in 82% yield, also as the PPN salt. From 2 a monohydrogen tetrametaphosphate ester [P4O10(OH)(OMe)](2-) (3, 96%) was derived by addition of methanol, illustrating that 2 can function as a reagent for chemical phosphorylation. Addition of water to 2 regenerates 1 quantitatively. Deprotonation of 1 by metal amides in the +2 oxidation state led to the unconventional monomeric tin(II) κ(4) tetrametaphosphate [Sn(P4O12)](2-) (4, 78%, a molecular analog of SnO) and binary dimeric chromium(II) bis(μ2,κ(2),κ(2)) derivative [Cr2(P4O12)2](4-) (5, 82%). Structural data stemming from single-crystal X-ray diffraction studies for the PPN salts of anions 1-5 are also reported.

The quantification of primary and secondary amines in plasma polymerized allylamine and plasma copolymers of allylamine/octadiene films was carried out using chemical derivatization followed by X-ray photoelectron spectroscopy. Data was analyzed using a combination of the peak-fit-analysis method (PFA) and the quantitative-elemental-analysis method (QEA). The latter method overestimates the secondary amine contribution, since it does not account for the additional reaction of TFAA with OH groups that may be present as a result of surface aging effects. In the current work the PFA method has been extended to enable the separation of –OH groups and secondary amines, thus allowing for a more precise determination of the secondary amine groups even after surface aging.

Operationally simple, efficient, and widely applicable Pummerer annulations of simple phenols with ketene dithioacetal monoxides, with the aid of trifluoroacetic anhydride, have been shown to provide a variety of benzofurans having a methylthio group at the 2-position. Subsequent and newly developed nickel-catalyzed arylation at the methylthio group culminates in diversity-oriented synthesis of multisubstituted benzofurans. Our extended Pummerer annulation/cross-coupling sequence is powerful enough to synthesize biologically active natural products as well as highly fluorescent benzofuran derivatives.

The enantiomeric ratio of methylamphetamine (MAMP) is closely related to the optical activity of precursors and reagents used for the synthesis and this knowledge can provide useful information concerning the origins and synthetic methods used for illicit manufacture. The information can be utilized for regulation of the precursors and investigation of the manufacturing sources but this requires analytical procedures to determine purity of drug substances, impurity profiling and enantiomeric composition. In this study, a gas chromatography (GC) coupled with mass spectrometry (MS) method using a γ-cyclodextrin chiral stationary phase was developed and optimized for the simultaneous enantiomeric separations of MAMP and its common precursors, ephedrine, and pseudoephedrine, as well as its chlorointermediates formed during MAMP synthesis by the Emde method, after derivatization with trifluoroacetic anhydride. The optimization was performed using multivariate statistics (cluster analysis and principal components analysis) in order to select and compare optimal experimental conditions. Under the optimized experimental conditions, the calculated calibration curves showed good linearity range up to 0.1 μg/mL for all tested analytes. The limits of detection were in the range of 0.002–0.008 μg/mL and the coefficient of variability was between 1.0 and 3.9%. The method has the advantage of achieving excellent precision under repeatability and reproducibility conditions while detection by MS allows for the identity of analytes to be confirmed in a single analysis. The method was therefore applied satisfactory to MAMP analysis.

Self-acylation of 3-(4-R-phenyl)propionic acids (R = H, Br, 1-adamantyl) in trifluoroacetic anhydride catalyzed by trifluoromethanesulfonic acid provides a simple and efficient synthesis of 1,3-diketones. Indan-1-ones formed in the first step undergo acylation to give the corresponding 2-(3-phenyl-1-oxopropyl) indan-1-ones as the major products. One-pot synthesis of polysubstituted pyrazoles directly from 3-(4-R-phenyl)propionic acids is described.

In this study, epoxy-terminated silicon oxide surfaces were chemically derivatized with trifluoroacetic anhydride (TFAA) and 4-(trifluoromethyl)-benzylamine (TFMBA) and analyzed by X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy and water contact angle measurements. TFAA was used for quantitative derivatization to determine the amount of reactive epoxy groups on these surfaces. Furthermore, epoxy-terminated surfaces were derivatized with TFMBA (a model compound for biomolecules with an amino linker) yielding secondary amines because of formation of covalent C–N bonds between TFMBA and the epoxy films. Fluorine being part of TFAA and TFMBA composition was used to follow the progress of the chemical derivatization reaction. Both derivatization agents – TFAA and TFMBA – gave comparable reaction yields of ~60% on epoxy silicon surfaces, whereas on epoxy glass slides, the derivatization yields were considerably lower (30–40%).The protocol for attachment of TFMBA (model compound) on epoxy-modified surfaces was adapted to (bio)molecules with an amino linker, e.g. carbohydrates to prepare carbohydrate-functionalized biointerfaces. Copyright © 2014 John Wiley & Sons, Ltd.

Electron-rich N-substituted pyrazoles smoothly reacted with trifluoroacetic anhydride in pyridine to form the corresponding trifluoromethyl ketones in good yields.

N-(3-Cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-2,2,2-trifluoroacetamide was synthesized by the acylation reaction of trifluoroacetic anhydride with 2-amino-4,5,6,7-tetrahydro-benzo[b]thiophene-3-carbonitrile, which was prepared via microwave-assisted Gewald reaction with K2CO3 as a heterogeneous solid base catalyst. This protocol presented such advantages as short reaction time, high yield, easy work-up and environmentally benign procedures. The structure of the title compound was confirmed by IR, 1H NMR, MS, elemental analysis and X-ray single-crystal diffraction method. X-Ray diffraction analysis reveals that the cyclohexene ring adopts a half-chair conformation and the thiophene ring is essentially planar.

The synthesis of 3,5-disubstituted 1,2,4-oxadiazoles by the cyclocondensation of amidoximes with trifluoroacetic anhydride or benzoic acid derivatives in moderate to high yields is described. The study on the phase transition behavior has disclosed that some of the synthesized oxadiazoles show smectic or nematic phases depending on their structures, which have the high potential application as liquid crystalline monomers.

Fully substituted glucomannan (GM) acylates with acyl carbon numbers ( n ) of 2, 3, 4, 5, 6, 8, 10, and 12 were prepared from konjac GM (KGM) in carboxylic acid/trifluoroacetic anhydride (TFAA). GM acetate acylates ( n = 3, 4, 5, 8, 12, 16, and 18) were prepared from KGM in acetic acid/carboxylic acid/TFAA. Differential scanning calorimetry (DSC) and X-ray diffraction revealed that the GM esters did not exhibit melting peaks and reflections derived from crystal, indicating they were amorphous. The glass-transition temperatures ( T g s) of the GM esters tended to decrease with increasing acyl carbon number, ranging from 174 °C for GM acetate (GMAc) to 64 °C for GM laurate (GMLa). Colorless and transparent GM ester films were obtained by solvent casting and thermo-pressing. The mechanical properties of the GM ester films were controlled by the acyl group structure.

The synthesis of 7-azaindoles from 3-alkynyl-2-aminopyridines using acidic conditions, namely, a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA), is described. This methodology resulted in the synthesis of fifteen 7-azaindoles, with most containing substituents at the 2- and 5-positions. The majority of these were tested for antimicrobial activity against a range of bacteria and yeasts. The 7-azaindoles displayed the best activity against the yeasts, particularly against Cryptococcus neoformans, where activities as low as 3.9 μg ml(-1) were observed.

Perfluoroketones are useful products and intermediates in medicinal chemistry. Herein, cobalt-mediated fluoroacylation of 1,3-dienes is described using perfluorinated anhydrides such as TFAA. The reaction is thought to proceed through a fluoroacylcobalt reagent formed in situ. Perfluoroacylation of 1,3 dienes can also be performed to attain longer chain perfluorinated ketones.

Highly soluble phenylethynyl-endcapped isoimide oligomers were synthesized using 2,3,3′,4′-biphenyltetracarboxylic dianhydride (3,4′-BPDA) and aromatic diamines as the monomers, 4-phenylethynyl phthalic anhydride (4-PEPA) as the end-capping reagent, and trifluoroacetic anhydride as the dehydrating agent; then high performance thermosetting polyimides and composites were produced from these oligomers via the thermal crosslinking reaction of the phenylethylnyl group and the material properties were fully investigated. A series of isoimide oligomers with different molecular weights and a variety of chemical architectures were prepared by polycondensation of 3,4′-BPDA, 4-PEPA, and aromatic diamines including m-phenylenediamine (m-PDA), 2,2′-bis(trifluoromethyl)benzidine (TFMB), and 3,4′-oxydianiline (3,4′-ODA), followed by cyclization with trifluoroacetic anhydride. These isoimide oligomers were characterized by means of gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), rheological measurements, intrinsic viscosity measurement, and solubility tests. Compared to their imide analogues, isoimide oligomers showed much higher solubility in low boiling point solvents, and slightly lower melt viscosity, which can be attributed to their unique asymmetric architecture. These resins were formulated into thermosetting polyimides and composites by thermal crosslinking of the phenylethynyl group and conversion from isoimide to imide at elevated temperatures. The properties of the thermosets and composites were studied using mechanical property measurements, dynamic mechanical thermal analysis (DMTA), and thermogravimetric analysis (TGA). The cured polyimides exhibited extremely high glass transition temperatures (Tg) up to 467 °C, and 5% weight loss temperatures (T5%) up to 584 °C in a nitrogen atmosphere. The polyimide/quartz fiber composites possessed excellent high temperature mechanical properties due to the high glass transition temperatures of matrix resins.

The microwave spectrum of trifluoroacetic anhydride (CF3COOCOCF3) has been recorded by chirped-pulse and cavity Fourier transform microwave spectroscopy. A dense b-type spectrum containing several P, Q, and R branch progressions has been assigned and fit to the Watson A-reduced asymmetric rotor Hamiltonian. No evidence of tunneling or internal rotation of the CF3 groups was observed. DFT calculations of the rotational constants are in good agreement with experimental results.

A new one-pot method was developed for the practical preparation of powerful electrophilic trifluoromethylating agent, 2,3,7,8-tetrafluoro-S-(trifluoromethyl)dibenzothiophenium triflate 2. This method comprised of three steps; (1) in situ generation of trifluoromethanesulfinyl trifluoroacetate 7, (2) treatment of 3,3′,4,4′-tetrafluorobiphenyl with 7 in the presence of trifluoromethanesulfonic acid and trifluoroacetic anhydride, and (3) treatment of the resulting mixture with hydrogen peroxide. By means of this effective three-step one-pot method, 2 was prepared in a good isolated yield by simple water-washing method. It is thus expected that easy access to 2 may lead to its wider or new applications to many areas, because tetrafluoro reagent 2 is much more powerful than 2,8-difluoro-S-(trifluoromethyl)dibenzothiophenium triflate 1.

A number of aliphatic and aromatic carboxylic acids were reacted with thiophene in the presence of trifluoroacetic anhydride and H3PO4 to give a variety of acylated thiophenes in good to excellent yields. The methodology was used to prepare known nonsteroidal anti-inflammatory drug-based novel compounds of potential pharmacological significances. Molecular modeling studies were carried out by using nonsteroidal anti-inflammatory drug-based thiophene derivatives to assess their cyclooxygenase inhibiting potential in silico. On the basis of docking studies followed by subsequent in vitro assay, indomethacin-based thiophene derivative was identified as a novel cyclooxygenase-2 inhibitor with balanced selectivity.

We report the new pendant furyl and thienyl fulgimides photochromic switch bearing polypyrroles. The functionalized pyrrole monomers synthesized and structures are ascertained by NMR and mass spectral techniques. The yield of fulgides and fulgimides are improved by using trifluoroacetic anhydride (TFA) as a dehydrating agent. The photo-switching properties of fulgimides monomers are explained by electronic structures of HOMO–LUMO of the monomers using Gaussian 03 packages. The electro-active polymer films deposited on indium tin oxide (ITO) electrodes are characterized by cyclic voltammetry and atomic force microscopy (AFM). The electrochemically formed thin films undergoes photo-switching between open and closed state of fulgimides moiety. The photo-switching properties of the polymer films have been confirmed by UV/vis spectroscopy. Though the films are photochemically stable, their mechanical stability with respect to adhesion to electrode is found to be sensitive to the solvent and electrode material.

Lithiation of N-(pyridin-3-ylmethyl)pivalamide, tert-butyl N-(pyridin-3-ylmethyl)carbamate, and N,N-dimethyl-N′-(pyridin-3-ylmethyl)urea with tert-butyllithium (3 equiv) in anhydrous tetrahydrofuran at –78 °C takes place on the nitrogen and on the ring at the 4-position. The dilithium reagents thus obtained react with various electrophiles to give the corresponding substituted derivatives in high yields. On the other hand, regioselective side-chain lithiation occurs with lithium diisopropylamide (3.3 equiv) at –20 to 0 °C. A mixture of ring and side-chain substitution products is obtained with n-butyllithium as the lithium reagent. Treatment of one of the ring-substituted products with trifluoroacetic anhydride in dichloromethane under reflux conditions led to formation of the corresponding 1H-pyrrolo[3,4-c]pyridine in high yield.

An efficient sp2 C–H hydroxylation has been developed for the synthesis of a wide range of functionalized phenols with aryl ketones, benzoates, benzamides, acetanilides and sulfonamides through palladium(II) catalysis. A trifluoroacetic acid (TFA)/trifluoroacetic anhydride (TFAA) co-solvent system serves as the oxygen source and is the critical factor for weak coordination promoted C–H activation.

E-mail: kimjn@chonnam.ac.krReceived April 30, 2013, Accepted June 6, 2013An efficient synthesis of 2,2'-dipyrryl ketones has been carried out from pyrrole-2-carboxylic acids usingtrifluoroacetic anhydride (TFAA). Simultaneous generation of both mixed anhydride and 2-unsubstitutedpyrrole, via facile decarboxylation with in-situ generated TFA, made their cross reaction (intermolecularFriedel-Crafts acylation) possible and efficient. Key Words : Dipyrryl ketones, Pyrrole-2-carboxylic acid, Trifluoroacetic anhydride, Mixed anhydrideIntroductionDipyrryl ketone derivatives have been studied extensivelydue to their synthetic usefulness as precursors for thesynthesis of porphyrin derivatives

An express method was developed for the simultaneous identification of bisphenol A, diethylstilbestrol, hexestrol, and dienestrol in canned foods, drinking water, and alcoholic and nonalcoholic beverages by gas-liquid chromatography with ECD and mass spectrometry detectors. Target compounds were extracted from foods with acetonitrile using QuEChERS method. Additional purification and concentration of the extract was carried out using dispersive liquid-liquid microextraction with carbon tetrachloride. These compounds were converted into the volatile derivatives with trifluoroacetic anhydride. Concentration range was 0.5–100 μg/kg. The identification of stilbene derivatives was carried out based on mass spectra. The duration of the analysis was 1–1.5 h, and the relative standard deviation of the analysis does not exceed 0.1.

A solvent-free quick synthesis of 1-(4′,6′-dimethylpyrimidin-2′-yl)-5-amino-4H-3-arylpyrazoles (3) was accomplished by grinding 2-hydrazino-4,6-dimethylpyrimidine (1) and β-ketonitriles (2) in the presence of p-Toluenesulfonic acid as a catalyst. Subsequently, 5-aminopyrazoles (3) were converted to their corresponding N-acetamide (4) and N-trifluoroacetamide (5) derivatives by treating (3) with acetic anhydride/acetic acid and trifluoroacetic anhydride/trifluoroacetic acid, respectively. The newly synthesized compounds were fully characterized using IR, NMR (1H, 13C, and 19F), mass spectral studies, and elemental analyses. All of the fifteen compounds were screened for their in vitro antibacterial activity against two Gram-positive and two Gram-negative pathogenic bacteria such as Bacillus pumilus, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, respectively. Additionally, nine of these compounds were screened for their cytotoxicity against the human Caucasian promyelocytic leukemia (HL-60) cell line using the alamarBlue® assay. Preliminary results reveal that compounds 3a, 3b, 3d, 5a, and 5d are showing moderate-to-significant cytotoxic and antibacterial activity.

A simple, rapid analytical procedure for the quantification of emamectin benzoate in tomato was developed using high performance liquid chromatography with fluorescence detector (HPLC-FLD). Emamectin benzoate residues were extracted from tomato samples with n-hexane:ethyl acetate (1:1, v/v). The method involved derivatization using trifluoroacetic anhydride and 1-methylimidazole, prior to analysis by HPLC-FLD. Limit of quantification of this method was found to be 0.01 mg/kg, while limit of detection was 0.005 mg/kg. The dissipation of emamectin benzoate on tomato was studied, and half-life (t1/2) was estimated in a field study carried out at three different locations. Emamectin benzoate was sprayed on tomato at recommended dosage. Samples of tomato were collected at 0, 1, 3, 7, 10, and 15 days after treatment. The t1/2 of emamectin benzoate when applied at the recommended doses in tomato was approximately 2.5 days. The residue of emamectin benzoate reached below the maximal residue limit (MRL) 10 days af...

The cobalt-catalyzed oxidation of methane to methyl trifluoroacetate by molecular oxygen in trifluoroacetic acid has been studied in detail. Yields of up to 50 % based on methane were obtained. The catalytic activities were highly dependent on the anions of the cobalt salts (CoII, CoIII) under investigation. Deactivation by precipitation of the cobalt catalyst could be prevented by the addition of trifluoroacetic anhydride.