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Heptafluoro-iso-butyronitrile (i-C3F7CN) represents a feasible eco-friendly replacement gas for the most potent greenhouse gas sulfur hexafluoride in various high-voltage power transmission equipment. The reaction mechanisms for the in situ synthesis of i-C3F7CN from heptafluoro-iso-butyramide [i-C3F7C(O)NH2] in the presence of trifluoroacetic anhydride (TFAA) and pyridine (Py) in dimethylformamide solution have been studied within density functional theory with M06-2X exchange–correlation functional with the 6-311++G(d,p) basis set and the high-level ab initio complete basis set quadratic CBS-QB3 method. It is revealed that the unimolecular dehydration of i-C3F7C(O)NH2 can be catalyzed efficiently by TFAA in terms of both kinetic and thermodynamic aspects, producing i-C3F7CN and trifluoroacetic acid (TFA). Furthermore, Py is capable of reducing the energy barrier of the rate-determining step through hydrogen abstraction to form pyridinium hydrogen. The synergic effect of the TFAA/Py co-catalyst plays a pivotal role in the production of i-C3F7CN as the Gibbs free energy barrier can be lowered by more than 40 kcal/mol with the ratio of TFAA:2Py, in accordance with the experimental observation. The present theoretical work provides new insights into the rational design on the novel catalysts for large-scale synthesis of the perfluorinated nitriles. [ABSTRACT FROM AUTHOR]

The effects of the ferrocenyl moiety to enhance the nucleophilicity of the carbonyl group, situated at its adjacent position, have been explored in a series of α-ferrocenyl ketocarboxylic acids. In the presence of trifluoroacetic anhydride, 3-ferrocenoylpropionic acid and 4-ferrocenoylbutyric acid gave 5-ferrocenyl-4-trifluoroacetyl-2(3H)-furanone and 6-ferrocenyl-5-trifluoroacetyl-3,4-dihydropyran-2-one, respectively. Under similar reaction conditions, 2-ferrocenylcarbonylbenzoic acid, a keto carboxylic acid without a β-hydrogen, gave a dimerized lactone, 3,3′-diferrocenyl-3,3′-diphthalide, possibly due to radical coupling. The nucleophilic attack of carbonyl oxygen, activated by the ferrocenyl moiety, on the carboxylic carbon is assumed to be the crucial mechanistic step in forming these lactones. When the carbonyl group was reduced to an alcohol to break its conjugation with the ferrocenyl moiety, saturated lactones were isolated after the acidic workup. These results indicate that the α-ferrocenyl carbinols readily undergo solvolysis under acidic conditions, giving ferrocenylcarbenium ions, which are attacked by the carboxy oxygen to give lactones. [ABSTRACT FROM AUTHOR]

Heptafluoro-iso-butyronitrile (i-C3F7CN) represents a feasible eco-friendly replacement gas for the most potent greenhouse gas sulfur hexafluoride in various high-voltage power transmission equipment. The reaction mechanisms for the in situ synthesis of i-C3F7CN from heptafluoro-iso-butyramide [i-C3F7C(O)NH2] in the presence of trifluoroacetic anhydride (TFAA) and pyridine (Py) in dimethylformamide solution have been studied within density functional theory with M06-2X exchange–correlation functional with the 6-311++G(d,p) basis set and the high-level ab initio complete basis set quadratic CBS-QB3 method. It is revealed that the unimolecular dehydration of i-C3F7C(O)NH2 can be catalyzed efficiently by TFAA in terms of both kinetic and thermodynamic aspects, producing i-C3F7CN and trifluoroacetic acid (TFA). Furthermore, Py is capable of reducing the energy barrier of the rate-determining step through hydrogen abstraction to form pyridinium hydrogen. The synergic effect of the TFAA/Py co-catalyst plays a pivotal role in the production of i-C3F7CN as the Gibbs free energy barrier can be lowered by more than 40 kcal/mol with the ratio of TFAA:2Py, in accordance with the experimental observation. The present theoretical work provides new insights into the rational design on the novel catalysts for large-scale synthesis of the perfluorinated nitriles.

Feasible, scalable, and cost-effective method for the synthesis of low-molecular 2-(trifluoroacetyl)oxazoles from the corresponding oxazoles and trifluoroacetic anhydride was elaborated. The procedure was scaled up to 70 g of the desired ketones in a single run. Tolerance of the oxazole core to various functional group transformations was demonstrated. Thus, synthesis of various building blocks approved the possibility of using 2-(trifluoroacetyl)oxazoles as a starting materials for medicinal chemistry. [ABSTRACT FROM AUTHOR]

Methods have been developed for the synthesis of symmetrical 1,3-bis(3-R-adamantan-1-yl)-acetones [R = OH, aryl, heteroaryl, R′C(O)NH, NH2C(S)NH] by CF3SO3H/(CF3CO)2O-catalyzed self-acylation of 2-(3-hydroxyadamantan-1-yl)acetic acid. [ABSTRACT FROM AUTHOR]

5-[3(4)-R-Adamantan-1-yl]salicylic acids [R = H, Alk, Ar, OH, NHC(S)NH2] have been synthesized by electrophilic substitution reactions of hydroxy- and bromoadamantanes with salicylic acid, as well as by reactions of 5-(3-hydroxyadamantan-1-yl)salicylic acid with carbon and nitrogen nucleophiles, in trifluoroacetic acid. The possibility of selective hydroxylation of the adamantane fragment in 5-(adamantan-1-yl)salicylic acid with sulfuric acid in trifluoroacetic anhydride has been demonstrated. [ABSTRACT FROM AUTHOR]

Trifluoroacetic anhydride was used as an efficient activator of the acylation of aryl methyl ketones with carboxylic acids in the presence of Brønsted and Lewis acids (SF3SO3H, MeSO3H, 4-MeC6H4SO3H·H2O, BF3·Et2O). In all cases, the products were the corresponding β-diketones. In the reactions in the presence of boron trifluoride–diethyl ether complex, the products were isolated as BF2-chelates with high yields. [ABSTRACT FROM AUTHOR]

Trifluoroacetic anhydride mediated one-pot intermolecular formal (4+2) benzannulation of oxygenated arylacetic acids with alkyl aryl ketones provides 4-aryl-2-arylacetoxynaphthalenes in moderate to good yields in the presence of H3 PO4 in an open-vessel in a straightforward procedure. A plausible mechanism is proposed and discussed. This protocol provides a highly effective ring-closure via two carbon–carbon (C–C) and one carbon–oxygen (C–O) bond-formation events. [ABSTRACT FROM AUTHOR]

A synthetic method for the radical trifluoromethylation of enol acetates using trifluoroacetic anhydride (TFAA) is reported. This photochemical reaction is operationally simple and employs economical reagents and readily accessible enol acetate precursors. The mild conditions and good scope render this method a useful addition to the repertoire of reactions employing TFAA as a trifluoromethyl source. [ABSTRACT FROM AUTHOR]

Direct α‐Trifluoromethylation of acetophenone derivatives was achieved by using trifluoroacetic anhydride (TFAA) as the trifluoromethyl source and pyridine‐N‐oxide (Py−O) as activator and oxidant under visible light irradiation and tris‐(2,2′‐bipyridine)ruthenium(II) hexafluorophosphate (Ru(bpy)3(PF6)2) as the photocatalyst. Different acetophenone derivatives could be converted to the corresponding α‐CF3 derivatives with high selectivity. Extensive mechanistic investigation revealed the formation of vinyl trifluoroacetate as the key intermediate for this transformation. [ABSTRACT FROM AUTHOR]

[Display omitted] The total syntheses of berberine hydrochloride and its analogues were achieved by a convergent strategy from available meconine derivatives, which were based on base mediated isoquinoline annulation followed by trifluoroacetic anhydride promoted decarbonylative elimination protocol. Key elements of our approach feature divergent synthesis, step-economy manner, multigram scalable synthesis, transition metal-free and chromatography-free purification. [ABSTRACT FROM AUTHOR]

In the current work, chemical derivatization of amine (NH 2 ) groups with trifluoroacetic anhydride (TFAA) as an analytical method to improve the information scope of X-ray photoelectron spectroscopy (XPS) is investigated. TFAA is known to successfully label hydroxyl (OH) groups. With the introduction of a newly developed gas-phase derivatization protocol conducted at ambient pressure and using a catalyst also NH 2 groups can now efficiently be labelled with a high yield and without the formation of unwanted by-products. By establishing a comprehensive and self-consistent database of reference binding energies for XPS a promising approach for distinguishing hydroxyl from amine groups is presented. The protocol was verified on different polymers, including poly(allylamine), poly(ethyleneimine), poly(vinylalcohol) and chitosan, the latter one containing both types of addressed chemical groups. [ABSTRACT FROM AUTHOR]

Abstract: An aluminium chloride‐mediated cascade reaction between pyrrolidones and trifluoroacetic anhydride is reported. Functionally diverse 1‐chloro‐2,2,2‐trifluoroethylidene‐substituted pyrrolidones were obtained in moderate to high yields through electrophilic trifluoroacetylation, nucleophilic chlorination, and elimination. This procedure has a wide scope, good functional‐group tolerance and the reaction conditions are amenable to scale up. Additionally the obtained 1‐chloro‐2,2,2‐trifluoroethylidene products can be applied to further functionalization as trifluoromethyl‐containing building blocks. Some of the title compounds showed fungicidal activity against cucumber downy mildew (CDM). [ABSTRACT FROM AUTHOR]

All-cellulose composites with a potential application as food packaging films were prepared by dissolving microcrystalline cellulose in a mixture of trifluoroacetic acid and trifluoroacetic anhydride, adding cellulose nanofibers, and evaporating the solvents. First, the effect of the solvents on the morphology, structure, and thermal properties of the nanofibers was evaluated by atomic force microscopy (AFM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), respectively. An important reduction in the crystallinity was observed. Then, the optical, morphological, mechanical, and water barrier properties of the nanocomposites were determined. In general, the final properties of the composites depended on the nanocellulose content. Thus, although the transparency decreased with the amount of cellulose nanofibers due to increased light scattering, normalized transmittance values were higher than 80% in all the cases. On the other hand, the best mechanical properties were achieved for concentrations of nanofibers between 5 and 9 wt.%. At higher concentrations, the cellulose nanofibers aggregated and/or folded, decreasing the mechanical parameters as confirmed analytically by modeling of the composite Young’s modulus. Finally, regarding the water barrier properties, water uptake was not affected by the presence of cellulose nanofibers while water permeability was reduced because of the higher tortuosity induced by the nanocelluloses. In view of such properties, these materials are suggested as food packaging films.

An efficient methodology has been developed for the synthesis of a variety of novel trifluoroacetylated enaminones by using trifluoroacetic anhydride in DCE as solvent and DBU as a base via electrophilic trifluoroacetylation. X-ray crystallographic studies confirmed the trifluoroacetylation and E stereoisomeric form of the novel compounds. The synthetic strategy has the advantage of using an inexpensive and non-toxic base for producing excellent yields. Synthons bearing variety of functional groups may be further extended for the formation of heterocyclic compounds. [ABSTRACT FROM AUTHOR]

Direct benzoylation of the two hydroxyl groups on chitosan was achieved using a phosphoryl mixed anhydride system, derived from trifluoroacetic anhydride (TFAA), benzoic acids (BAs), and phosphoric acid (PA). The reaction is operated as a one pot process under mild conditions that does not require neither an inert atmosphere nor dry solvents. The structures of the synthesized compounds were confirmed by NMR and IR spectroscopy. Solubility tests on the products revealed that they were soluble in organic solvents such as N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), and acetone. In the meantime, a morphological study by scanning electron microscopy (SEM) evidently indicated that the chitosan benzoates underwent significant structural changes after the benzoylation.

Chitin benzoic acid esters were prepared using a phosphoryl mixed anhydride method. The products were characterized by 1H-NMR and FT-IR spectroscopy. FT-IR analysis revealed that the degree of O-acyl substitution of the products was in a range of 1.17–1.83. Morphological surface changes in the parent molecule due to the introduction of benzoic acid moieties were observed by scanning electron microscopy. The surface of the products was porous, in contrast to the sheet-shape of the parent molecules. The solubility of the products, which improved with increased degree of acid substitution, was tested in various organic solvents.

Synthesis of a series of new N-4-(N-2-(trifluoromethylphenyl))sulfamoyl amide derivatives 6(a-i) was accomplished by a sequence of reactions by using aniline as a starting compound (1). The newly synthesized compounds were characterized by the spectral analysis and evaluated their antibacterial activity. 5-Nitro-N-(4-(N-(2-(trifluoromethyl)phenyl)sulfamoyl)phenyl)furan-2-carboxamide (6b) exhibited the highest activity. [ABSTRACT FROM AUTHOR]

Secondary alcohols were conveniently tritylated under mild conditions within a short running time with tritylium trifluoroacetate generated in situ from trityl alcohols and trifluoroacetic anhydride. No expensive silver salts were needed for the reactions. Four secondary alcohols were tritylated with both mono- and dimethoxy trityl alcohols giving good to excellent isolated yields. The reaction was also tested on four nucleoside derivatives that have primary alcohols. Satisfactory results were also obtained. [ABSTRACT FROM AUTHOR]

In this study, five-membered heterocyclic compounds are trifluoroacetic acylated for the purpose of providing more long pairs to enhance electrolyte in dye sensitized solar cells (DSSCs). Four five-membered heterocyclic compounds will be trifluoroacetic acylated with trifluoroacetic anhydride by Friedel-Crafts acylation: furan, thiophene, pyrrole and N-methylpyrrole. The properties will be measured by cyclic voltage (CV), Fourier transform infrared spectroscopy (FTIR), solar simulator, and electrochemical impedance spectroscopy (EIS). We find out that furan and thiophene which we add in electrolyte as additives can increase short circuit current and photovoltaic efficiency, and furthermore, all the trifluoroacetic acylated heterocyclic compounds perform better photoelectric abilities than non-trifluoroacetic acylated one. The photovoltaic efficiency will be increased from 4.439% to 5.197% when 1wt% trifluoroacetic acylated thiophene is added in electrolyte as additives. [ABSTRACT FROM AUTHOR]