Boron Trifluoride Etherate Research Articles

Synthesis of diesters by addition of saturated carboxylic acids to tricyclodecenyl formate

Reaction of addition of C1-C5-saturated monobasic acids to tricyclo[5.2.1.02.6]dec-3-en-8(9)-yl for-mate in the presence of a catalyst, boron trifluoride etherate (BF3·OEt2), was used to synthesize homo- and mixed tricyclo[5.2.1.02.6]decane-3(4),8(9)-diol diesters. The synthesized formic-acetic and formic-propionic acid diesters have a pleasant odor and can be used as components for preparation of perfume formulations.

Synthesis, crystal structure, property research, and DFT calculation of 2,3-diphenylfuro[3,2-b]quinoxaline

The title compound is obtained via the intramolecular condensation of 3-(2-oxo-1,2-diphenylethyl)quinoxalin-2(1H)-one in the presence of excessive boron trifluoride etherate and characterized by 1HNMR, 13CNMR, IR, and EI-MS. The solution-based and solid-state fluorescence along with the electrochemical property are studied in detail. The unique herring-bone arrangement which is revealed by the X-ray crystallography should account for the intense solid-state fluorescence. The theoretic calculations are employed to clarify the origin of the large Stokes shift and the positive solvatochromism in view of the geometric relaxation and the transition feature.

Weinreb amide as an efficient reagent in the one pot synthesis of benzimidazoles and benzothiazoles

One pot synthesis of 2-substituted benzimidazoles/benzothiazoles through condensation is followed by cyclization of Weinreb amide with o-diaminoarene or o-aminothiophenol is reported. In the presence of boron trifluoride etherate in 1,4-dioxane solvent, a high yield (75–94%) was achieved within 60min. Weinreb amide shows high selectivity in the reaction, even in presence of other active functional groups such as carboxyl, halogen, cyano, and methoxy. [Display omitted]

A new synthesis of 4′-resveratrol esters and evaluation of the potential for anti-depressant activity

The 4′-ester analog of the disease preventative resveratrol 1 (RV), 4′-acetyl-RV 2 along with 4′-pivaloate 13 and benzoate 14 RV were synthesized. The previously developed palladium catalyzed decarbonylative Heck coupling was used to assemble the stilbene core together with 3,5-dibenzyl protected phenol intermediates that allowed for efficient coupling and deprotection using boron trifluoride etherate. Studies with Long-Evans rats were performed to establish safety, toxicity, and behavioral parameters. In addition, the Porsalt forced-swim test was used to demonstrate anti-depressant activity.

Tricolor electrochromism of PEDOT film electrodeposited in mixed solution of boron trifluoride diethyl etherate and tetrahydrofuran: Hypsochromic effect

PEDOT [poly (3,4-ethyldioxythiophene)] films have been electrochemically prepared in mixed solution of boron trifluoride diethyl etherate and tetrahydrofuran (BFEE-THF). The film shows tricolor electrochromism which is claret red at −0.8 V, light grey at 0.2 V, and sea blue at 1.0 V. The film retains 74% of the original electroactivity and unperturbed electrochromic behaviors after 3000 cycles indicating potential applications on EC devices. Spectroelectrochemistry indicates that the π-π* transition absorption peak (λmax) in the neutral state is located at 512 nm and the calculated energy gap (Eg) is 1.76 eV by the onset wavelength. Compared to the electropolymerization of PEDOT films in conventional solvent, tricolor electrochromism can be ascribed both to the low onset oxidation potential and polymerization rate in BFEE-THF, which may result in a low conjugation length of PEDOT. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Chain termination in polymerization of substituted oxetanes in the presence of boron trifluoride etherate

It has been shown that the polymerization of oxetanes with azidomethyl substituents initiated by boron trifluoride etherate in the absence and the presence of ethylene glycol proceeds via chain termination with fluorine atom transfer. This reaction results in the formation of a polymer that is monofunctional with respect to hydroxyl groups and contains a fluorine atom at one of the chain ends. With the use of 19F NMR spectroscopy, the number-average functionality of polymer with respect to fluorine atoms was studied. The methods of suppressing the aforementioned reaction, whose intensity decreases during a decrease in the polymerization temperature and an increase in the ethylene glycol concentration, were considered. In the absence of ethylene glycol, the chain termination with fluorine atom transfer is the main reaction of chain-propagation restriction.

Aminoalkylation of Indoles with α‐Polyfluoroalkylated Cyclic Imines

AbstractThe reaction of cyclic ketimines with indoles was studied. A dramatic difference between the electrophilicity of perfluoroalkyl‐substituted and non‐fluorinated imines was demonstrated. In good agreement with our calculations, the Friedel–Crafts‐type alkylation of indoles only takes place with α‐polyfluoroalkylated cyclic imines that are activated by boron trifluoride–diethyl ether. The reaction proceeds under mild conditions and provides the opportunity to obtain promising alkaloid‐like structures that contain a fluoroalkyl group. As a result, α‐CF3‐ and α‐C2F5‐substituted pyrrolidines, piperidines, and azepanes that contain an indole moiety can be prepared efficiently.

Highly Emissive Boron Ketoiminate Derivatives as a New Class of Aggregation‐Induced Emission Fluorophores

A series of boron ketoiminate derivatives that exhibited clear aggregation-induced emission (AIE) characteristics (in THF: Φ(PL)≤0.01; in the solid state: Φ(PL)=0.30-0.76) were prepared by the reactions of 1,3-enaminoketone derivatives with boron trifluoride-diethyl etherate. The structures and optical properties were investigated by UV-visible spectroscopy, photoluminescent (PL) spectroscopy, and X-ray single-crystal measurements. These results indicate that the AIE characteristics were derived from molecular motions of the boron-chelating rings with a boron-nitrogen (B-N) bond. Furthermore, the optical properties were controllable by steric hindrance of the substituted groups on the nitrogen atom.

Aromatic fluoro-de-triazenation with boron trifluoride diethyl etherate under non-protic acid conditions

Fluoro-de-triazenation of 3,3-diethyl-1-aryltriazenes can be achieved by conventional or under microwave heating in carbon tetrachloride, in the presence of boron trifluoride diethyl etherate without any protic acid to avoid corresponding unwanted byproduct formation.

Mild Double Allylboration Reactions of Nitriles and Acid Anhydrides Using Potassium Allyltrifluoroborate

The double allylboration of nitriles and acid anhydrides to form bis-allyl amines and esters, respectively, can be achieved through the use of potassium allyltrifluoroborate in the presence of boron trifluoride etherate at room temperature. The method described is relatively mild, exhibits chemoselectivity to other electrophiles present, avoids the use of metals, and features the use of an operationally stable and robust potassium organotrifluoroborate reagent.

Charge-transporting 3,4-ethylenedioxythiophene-based hydrazone monomers and oligomers

3,4-Ethylenedioxythiophene-based hydrazones, containing reactive functional groups were synthesized and their optical, thermal, photophysical and electrochemical properties were studied. The monomers were subjected to cationic polymerization using boron trifluoride etherate as an initiator. The ionization potentials of the films of the hydrazones, measured by the electron photoemission technique, range from 5.53 to 5.62 eV. Room temperature time-of-flight hole mobilities in the solid solutions of 3,4-ethylenedioxythiophene hydrazone monomers in bisphenol-Z polycarbonate exceed 10−5 cm2 V−1 s−1 at high applied electric fields.

The Study of Nucleophlic and Electrohilic Reaсtions of Bis- and 3-Substituted Chroman-2, 4-Dions

Aims: Here we study nucleophilic and electrophilic reactions of bis - and condensed 3substituted chroman-2,4-dions to produce polychromeno (thio)pyrans and trioxaoxonium benzonaphthotetracene salts. Place and Duration of Study: Saratov State University, Chemistry Institute, between September 2011 and July 2012. Results: Reactions of phenylmethylene bis -chroman-2,4-dion, 3-substituted chroman-2, 4dion with nucleophilic and electrophilic reagents were studied. Intramolecular Oheterocyclization to polyheteronuclear systems with key chromeno (thio) pyrano fragments of various saturation degrees is shown to be characteristic of the compounds studied. It is noted that phenylmethylene bis chroman-2,4-dion, under the action of phosphorus pentasulfide and hydrogen sulfide in situ, forms bis chromeno thiopyrans. Conclusion: Optimal heterocyclization conditions for 3-substituted chroman-2,4-dion with boron trifluoride etherate to trioxaoxonium benzonaphthotetracene salts were found.

Stereoselective Synthesis of Tetrahydroquinolines Through an Imino‐Ene Cyclization Reaction

AbstractTetrahydroquinolines have been efficiently synthesized in good yields with excellent stereoselectivity. The reaction between α‐allylic anilines and aldehydes proceeds through an imino‐ene cyclization that is mediated by boron trifluoride–diethyl ether.

Fluorescent Poly(2,6-dimethoxynaphthalene) Electrochemically Synthesized for Sensitive Detection of Imidacloprid Pesticide

Conducting poly (2,6-dimethoxynaphthalene) (PDMN), a novel fluorescent polymer was electrochemically synthesized in boron trifluoride diethyl etherate (BFEE) containing additional concentrated sulfuric acid via direct anodic oxidation of 2,6-dimethoxynaphthalene (DMN). The oxidation potential onset of DMN in this medium was 0.43 V, lower than other electrolyte media. PDMN films showed good electrochemical behavior and thermal stability. The structure and morphology of the polymer were investigated in detail. Fluorescent spectra indicated that the electrochemically polymerized PDMN was an excellent blue light-emitting material. The insoluble PDMN film deposited on the indium tin oxide glass was used to develop a sensor for the determination of imidacloprid based on the fluorescence quenching of PDMN. The interaction of imidacloprid and PDMN was investigated by electrochemical techniques. The fluorescent intensity of PDMN has a good linear relationship with the concentration of imidacloprid on the surface of PDMN in the range of 4.994 × 10−1 to 2.557 × 102 μg/mL with a detection limit of 3.093 ng/mL. The sensor based on PDMN films showed high recognition ability for imidacloprid and will have more potential applications in the industrial or environmental and healthy fields.

Boron Trifluoride Etherate Induced Stille Cross-Coupling Reaction of Aryltriazenes with Tributyl(phenyl)stannane Catalyzed by Recyclable Pd/C Catalyst

Boron Trifluoride Etherate Induced Stille Cross-Coupling Reaction of Aryltriazenes with Tributyl(phenyl)stannane Catalyzed by Recyclable Pd/C Catalyst

Low-potential electrosynthesis of novel electroactive poly(9-fluorenemethanol) and its electrochromic and blue-light-emitting properties

In this paper we describe the electropolymerization of 9-fluorenemethanol (FMO) in boron trifluoride diethyl etherate, which leads to low-potential electrodeposition of semiconducting poly(9-fluorenemethanol) (PFMO) film under optimized conditions. The as-formed PFMO film shows favorable solubility in common organic solvents, good redox activity and stability with a conductivity of 10−2Scm−1, good thermal stability, and uniform morphology. Besides, PFMO exhibits electrochromic nature with its color changing from pale brown in its reduced form to dark blue upon oxidation, but its electrochromic performances are relatively poor. Fluorescence spectral studies demonstrated that soluble PFMO is highly fluorescent with its maximum emission at 418nm and a quantum yield of 0.52, and it can emit bright blue light under 365nm UV light irradiation.

Synthesis and Characterization of Clickable Cytocompatible Poly(ethylene glycol)-Grafted Polyoxetane Brush Polymers

We report a new family of clickable poly(ethylene glycol) (PEG)-grafted polyoxetane brush polymers as a potential modular platform for delivery of drugs and imaging agents. 3-Ethyl-3-hydroxymethyloxetane (EHMO) monomer reacted with propargyl benzenesulfonate in the presence of sodium hydride to yield alkyne-substituted monomer (EAMO). Subsequently, cationic ring-opening polymerization using boron trifluoride diethyl etherate catalyst and 1,4-butanediol initiator produced P(EAMO) homopolymer with a DP of ∼30 (30 alkynes per chain). Methoxypoly(ethylene glycol) azide (mPEG750-azide) prepared from mPEG750 (750 g mol–1) was grafted to P(EAMO) via copper(I)-catalyzed alkyne–azide cycloaddition (CuAAC) click chemistry. Water-soluble cytocompatible P(EAMO)-g-PEG brush polymers with controlled degrees of PEGylation were synthesized by varying the feed molar ratio of mPEG750-azide to alkyne (25:100, 50:100, 75:100, and 100:100). 1H NMR, GPC, end-group analysis, FTIR, and DSC were applied for polymer characterizati...

Multicolor electrochromism of low‐bandgap copolymers based on pyrrole and 3,4‐ethylenedioxythiophene: Fine‐tuning colors through feed ratio

AbstractThe copolymerization of pyrrole with 3,4‐ethylenedioxythiophene (EDOT) is successfully achieved in boron trifluoride diethyl etherate via direct anodic oxidation of the monomer mixtures on indium‐tin oxide working electrodes. The resultant copolymers are characterized by electrochemical methods, FT‐IR, XPS, SEM, and spectroelectrochemical analysis. The copolymer films present excellent electrochromic properties especially the multicolor electrochromism which can be tuned through the feed ratio of pyrrole and EDOT. The neutral copolymer films exhibit blue‐shift with the increasing feed ratio of pyrrole and EDOT, and the calculated band gaps of the copolymers are as low as that of PEDOT film. Furthermore, the electrochemical and optical stability has been improved by the incorporation of EDOT units into the polymer chains. The copolymer prepared with the changing feed ratio of pyrrole and EDOT at 1/4 retains 71% of its original electroactivity after 500 cycles and 72% of its optical contrast after 500 steps. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Synthesis, characterization and fluorescence properties of boron difluoride pyridyl-β-diketonate derivatives

Five pyridyl-β-diketones were synthesized by Claisen condensation of ethyl nicotinate with various aryl methyl ketones in benzene in the presence of sodium amide as the base, and then reacted with boron trifluoride diethyl etherate in dichloromethane to afford some new boron difluoride pyridyl-β-diketonate derivatives. The compounds obtained were characterized using FTIR, 1H NMR, elemental analysis and mass spectrometry. Their optical properties were studied in DMF by UV–vis absorption and fluorescence spectroscopy. The results showed that these boron complexes exhibited intense fluorescence in the blue–green region (420–490nm) under UV radiation with a relatively high quantum yield. Especially, compounds 4b and 5b displayed much higher quantum yield as compared to compounds 1b, 2b and 3b.

Tricolor electrochromism of copolymer based on selenophene and 3,4-ethylenedioxythiophene

A copolymer based on selenophene and 3,4-ethylenedioxythiophene was successfully synthesized by electrochemical polymerization in boron trifluoride diethyl etherate (BFEE). The resultant copolymer was characterized by cyclic voltammetry, FTIR, XPS, SEM and spectroelectrochemistry. The copolymer presented tricolor electrochromism, which was dark green-yellow (in the neutral state), blue-green (in the intermediate state) and blue (in the oxidized state). Furthermore, the optical contrast and switching time of the copolymer was found to be 19.8% and 3.2s at 728nm, respectively, which remained 75.1% of its original electroactivity after 200 cycles.