Trifluoroacetophenone Derivatives Research Articles

Substantiation of the Selection of Trifluoroacetophenone Derivatives for the Manufacture of Membranes of Sulfate- and Carbonate-Selective Electrodes

The distribution of trifluoroacetophenone (TFAP) and its derivatives—p-methyl trifluoroacetophenone (p-MTFAP), 2,4-dimethyl trifluoroacetophenone (DMTFAP), 2,4,6-trimethyl trifluoroacetophenone (TMTFAP), and heptyl p-trifluoroacetylbenzoate (H-p-TFAB)—in a hexane–water system, which simplifies a polyvinylchloride membrane of selective electrodes, is studied by UV spectrophotometry and chromatography. These substances are used as neutral carriers (NCs) in membranes of ion-selective electrodes reversible to doubly charged carbonate and sulfate ions. The hydration of TFAP and some of its derivatives is systematically investigated. It is found that TFAP has higher solubility in water (partition coefficient D = 415) compared to those of p-MTFAP, DMTFAP, TMTFAP, and H-p-TFAB (D = 1360–2700), which makes it unsuitable as a neutral carrier for manufacturing membrane electrodes. H-p-TFAB is most strongly hydrated in an alkaline medium. It is found that p-MTFAP and H-p-TFAB form crystalline hydrates. The selectivity coefficients for the carbonate- and sulfate-selective electrodes are determined for all the neutral carriers studied; the selectivity of the electrodes increases in the series TFAP < p-MTFAP < DMTFAP < TMTFAP < p-BTFAP (p-butyl trifluoroacetophenone) < H-p-TFAB.

Practical Synthesis of 1,1-Difluoro- or 1-Fluoroalkenes from 2,2,2-Trifluoroacetophenone Derivatives

Since the discovery of the fact that compounds bearing a vinylic fluoride moiety often exhibit remarkable biological activities such as enzyme inhibitors, many synthetic methods for fluorine-substituted vinylic compounds have been developed. The synthesis of selectively fluorinated building blocks, such as arylsubstituted fluoro-alkenes, also has become an area of interest in recent years. Herein we describe a novel and practical method for the synthesis of 1,1-difluoro- and 1-fluoroalkenes starting from easily accessible trifluoroacetophenone derivatives. Various 1,1-difluoro- and 1-fluoroalkenes were prepared by the reaction of the corresponding tosyl hydrazones that were derived from trifluoroacetophenone derivatives by treating with alkyl or aryllithium reagents via addition-elimination and single electron transfer (SET) mechanism.

Potentiometric Polymeric Film Sensors Based on 5,10,15-tris(4-aminophenyl) Porphyrinates of Co(II) and Cu(II) for Analysis of Biological Liquids

Novel carbonate-selective potentiometric sensors based on 5,10,15-tris(4-aminophenyl)-20-phenyl porphyrinates of Cu(II) and Co(II) have been developed. Ionophore functioning mechanism and possible source of carbonate sensitivity have been evolved. Potentiometric properties of Co(II)- and Cu(II)TATPP-based sensors were compared with common carbonate-ISEs containing trifluoroacetophenone derivatives. The analytical utility of newly developed sensors has been demonstrated by measuring the bicarbonate content in human blood plasma.

Novel trifluoroacetophenone derivatives as malonyl-CoA decarboxylase inhibitors

A series of trifluoroacetophenone derivatives were prepared and evaluated as malonyl-CoA decarboxylase (MCD) inhibitors. Some of the ‘reverse amide’ analogs were found to be potent inhibitors of MCD enzyme activity. The trifluoroacetyl group may interact with the MCD active site as the hydrate in a similar fashion to the hexafluoroisopropanol analogs reported previously. Adding electron-withdrawing groups to the phenyl ring stabilizes the hydrated species and enhances this interaction.

Effect of solvating additives on anion-exchange extraction of trichloroacetate anions from aqueous solutions with trinonyloctadecylammonium picrate in toluene

The solvation effect of trifluoroacetophenone derivatives on anion-exchange extraction of trichloroacetate anions from aqueous phase with trinonyloctadecylammonium picrate in toluene was studied.

Carbonate Sensors Based on 4‐Hexyltrifluoroacetophenone Modified by Acceptor Substituents in Phenyl Ring

AbstractCarbonate sensors based on 4‐hexyltrifluoroacetophenone (Hex‐TFA) and its 3‐nitro‐ and 3‐bromo‐derivatives (NO2‐TFA and Br‐TFA) were studied. The acceptor substituents in phenyl ring of Hex‐TFA increase Lewis acidity of fluoroketone group and provide better carbonate selectivity of ionophore against lipophilic anions. The sensors containing hexyl trifluoroacetylbenzoate (HE) were used as reference. Variation of membrane composition and plastisizer were performed to optimize the selectivity. Potentiometric properties of carbonate sensors such as sensitivity, selectivity, detection limit (DL) and pH‐dependence of sensor response were studied. The sensors based on NO2‐TFA demonstrated significantly better selectivity than the sensors based on unmodified Hex‐TFA, the effect was up to three orders of magnitude for salicylate and nitrate, more than four orders for thiocyanate. However, NO2‐TFA sensors exhibited higher pH‐dependence of sensor response and higher detection limits. The sensors based on Br‐TFA showed the properties similar to that of HE‐based sensors. These results allow recommending trifluoroacetophenone derivatives with acceptor substituents in phenyl ring as promising ionophores for carbonate sensors.

Synthesis of Tripodal Trifluoroacetophenone Derivatives and Their Evaluation as Ion‐Selective Electrode Membranes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Tripodal Trifluoroacetophenone Derivatives and Their Evaluation as Ion-Selective Electrode Membranes

symmetric, tripodal trifluoroacetophenone derivatives 1-3 have been synthesized as anion ionophores.Evaluation of their ion selectivity has been carried out through ion-selective electrode membranes. Theselectivity coefficients for the carbonate electrode toward various anions are dependent on the composition ofthe membranes and the lipophilicity of the ionophores. The tripodal ionophore 1a showed an improvedselectivity toward salicylate when 90 mol% of a lipophilic additive was used, compared to that ofp-dodecyltrifluoroacetophenone. Key Words : Tripodal ionophores, Trifluoroacetophenone, Carbonate anion, Ion-selective electrodeRecently selective recognition and sensing of anions byartificial receptors have attracted a considerable researchinterest in view of their potential applications in variousareas.

Trifluoroacetophenone derivatives as amino acid selective ionophores for the potentiometric determination of phenylalanine.

Selective sensors: Trifluoroacetophenone derivatives were synthesized with a hexasubstituted benzene ring as a preorganized spacer (see scheme) and their characteristics as ionophores were examined for use in ion-selective electrodes. The electrode membranes based on these neutral carriers combined with a cationic additive showed a monoanionic Nernstian response to underivatized phenylalanine, with excellent selectivity towards other essential amino acids and inorganic anions. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2002/z18872_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Trifluoroacetophenone Derivatives as Amino Acid Selective Ionophores for the Potentiometric Determination of Phenylalanine This work was supported by the Ministry of Education, Science and Culture of Japan and the Kanagawa Academy of Science and Technology (KAST). D.C. gratefully acknowledges a research fellowship granted by the Science and Technology Agency of Japan (STA).

Trifluoroacetophenone Derivatives as Amino Acid Selective Ionophores for the Potentiometric Determination of Phenylalanine This work was supported by the Ministry of Education, Science and Culture of Japan and the Kanagawa Academy of Science and Technology (KAST). D.C. gratefully acknowledges a research fellowship granted by the Science and Technology Agency of Japan (STA).

Carbonate ion selective electrodes with trifluoroacetophenone derivatives in potentiometric clinical analyser

Properties of six derivatives of 1-trifluoroacetylbenzene: [4-( n-butyl)- (1), 4-( n-hexadecyl)- (2), 4-dodecyloxy- (3), 4-( n-dodecylsulfonyl)- (4), N,N-dioctyl-4-trifluoroacetylbenzamide (5), octyl- p-trifluoroacetylbenzoate (6)] as neutral carriers for carbonate ion were examined and compared. The sensitivity towards carbonate ion was for (3) pH dependent. This eliminates (3) from practical applications in clinical analysis. When measuring CO 3 2− within the physiological range of human blood using as carriers compounds 1 and 2 the interference of chloride must be taken into account. In the case of carriers 4, 5, 6 this effect is negligible. Electrodes with membranes containing as carriers 2, 4, 5 and 6 were tested in an automatic potentiometric clinical analyser Microlyte 6, KONE. To avoid contamination by atmospheric CO 2 of three aqueous standards (TES, NaCl, NaHCO 3), pH was adjusted by coulomeric generation of H + or OH − in a system devoid of carbon dioxide. Recovery of HCO 3 − calculated from measured CO 3 2− and pH, was investigated in a series of aqueous solutions and spiked bovine serum samples. The correlation between added and recovered concentration of HCO 3 − was linear with the intercept close to 0 and slope equal to 1 in aqueous solutions for all ligands and in bovine serum samples only in the case of ligand (2).

Observations on the behaviour of some trifluoroacetophenone derivatives as neutral carriers for carbonate ion-selective electrodes

Properties of three derivatives of trifluoacetophenone [4-(n-butyl)-1-trifluoroacetylbenzene (BTFAB), 4-(n-hexadecyl)-1-trifluoroacetylbenzene (HDTFAB), p-dodecyloxytrifluoroacetylbenzene (DDTFAB)] as neutral carriers for carbonate were examined. The best electrode characteristic (slope, S= 29 mV decade–1, lowest detection limit) was for HDTFAB. The sensitivity towards carbonates was for DDTFAB pH dependent. This eliminates DDTFAB from practical applications. A theoretical treatment concerning carbonate and hydrogencarbonate selectivity under investigated conditions has been performed. Preliminary determination of carbonate in bovine serum was made using electrodes with HDTFAB.

Asymmetric cellulose acetate membrane-based carbonate- and chloride-selective electrodes

The potentiometric response characteristics and analytical applications of asymmetric cellulose triacetate (CTA) membrane systems are examined by employing trifluoroacetophenone derivatives and metalloporphyrins as the carbonate and chloride ionophores, respectively. The asymmetric membranes are characterized by having a hydrophilic, porous layer on top of the sensing surface of the ion-selective layer and by showing a decreased interference from large, hydrophobic anions by the kinetic and exclusion mechanism. The performance of the asymmetric membrane is optimized by employing different hydrolysis times or different plasticizers. A new approach of forming a hydrophilic layer is described in which asymmetric membranes are formed by hydrolyzing directly the surface of homogeneous, plasticized CTA-matrix ion-selective membranes containing ion carriers. The analytical utility of the asymmetric membranes is demonstrated by employing the chloride-selective asymmetric membrane for serum chloride measurements. It is shown that the asymmetric membrane-based chloride-selective electrode exhibits a remarkably reduced response to salicylate, compared to the conventional PVC-or unmodified CTA-matrix membrane electrodes.

Development of an ethanol-selective optode membrane based on a reversible chemical recognition process

Lipophilic trifluoroacetophenone derivatives incorporated in plasticized PVC membranes are able to selectively extract water and alcohols from the sample solution into the organic membrane phase, reversibly forming hydrates and hemi-acetals, respectively. Since this is accompanied by a change in the absorption spectrum of the acetophenone isologue, the chemical recognition process can directly be translated into an optical signal. With N-acetyl- N-dodecyl-4-trifluoroacetylaniline (ETH 6022) as the electrically neutral, lipophilized carrier ethanol can be determined from 0.5 to 35% (v/v) in aqueous solutions. The calibration curve for different ethanol-water mixtures shows a good correlation with the mathematically derived formalism and thus confirms the theoretically expected behavior. Besides high reproducibility of the optical signals, very short response times of less than 30 s were realized. The optode membrane presented exhibits a preference for ethanol compared to water by a factor greater than 11. The selectivities for several primary alcohols, such as methanol, ethanol, 1-propanol and 1- n-butanol, are comparable, but isopropanol and tert.-butanol are rejected by a factor of about 10. The alcohol concentration in different beverages was determined to evaluate the reliability of the system. The values obtained for wine, beer and different spirits show an excellent correlation with those obtained by a conventional approach involving distillation and density measurements. A residual standard deviation of ± 0.27% (v/v) over the 0.7–40% (v/v) range was found.

Anion selectivities of trifluoroacetophenone derivatives as neutral ionophores in solvent-polymeric membranes

Trifluoroacetophenones with different substituents in the para-position are studied in order to examine their anion selectivities in solvent-polymeric membranes. The selectivities of the corresponding ion-selective electrodes and the hydration of the ligands in membranes depend on the Hammett constants σ of the substituents. Better selectivities for carbonate over chloride were reached throughout for ligands with substituents of high σ values.

Electron-capture detection of tertiary aromatic amines after ring trifluoroacetylation

Trifluoroacetyl substitution in the aromatic ring (C-acylation) of N,N-dimethylaniline and N,N-dimethyl- p-toluidine is described; the reaction is catalyzed by trimethylamine. The resulting trifluoroacetophenone derivatives elicit a high response from an electron-capture detector (3–4 × 10 −16 mole/sec) and are well suited to quantitative determinations.