Boron Trifluoride Etherate Research Articles

Synthesis of [5,6]-fused pyridocoumarins through aza-Claisen rearrangement of 6-propargylaminocoumarins

[5,6]-Fused pyridocoumarins are prepared through aza-Claisen rearrangement and subsequent in situ cyclization of 6-propargylaminocoumarins under microwave irradiation in the presence of boron trifluoride diethyl etherate in N, N-dimethylformamide. During this process demethoxycarbonylation is observed in the corresponding 4-carbomethoxycoumarin derivatives.

Electrochemical Polymerization of N-(9-Fluorenylmethoxycarbony)-Glycine and Characterization of its Polymers

Poly(N-(9-fluorenylmethoxycarbony)-glycine) (PFG) film was first synthesized on platinum wire by direct anodic oxidation of N-(9-fluorenylmethoxycarbony)-glycine (FG) in boron trifluoride diethyl etherate (BFEE). The oxidation potential of FG in BFEE was only 0.4 V vs. Pt. Therefore, BFEE can be an ideal supporting electrolyte for polymerization of FG. Scanning electron microscopy showed the morphology of PFG. The structure of PFG film was studied by FT-IR spectroscopy.

Poly[N-(9-Fluorenylmethoxycarbonyl)-L-Phenylalanine] with Good Solubility and Good Blue Light-Emitting Properties via Electropolymerization

Poly[N-(9-fluorenylmethoxycarbonyl)-L-phenylalanine] (PN9FPA) films with good fluorescence properties and good solubility were prepared electrochemically by direct anodic oxidation of N-(9-fluorenylmethoxycarbonyl)-L-phenylalanine (N9FPA) in boron trifluoride diethyletherate (BFEE). The structures of the monomer and the polymers were characterized and evaluated with IR. The fluorescence spectra indicated that PN9FPA films were blue-light emitters.

New System of Deprotection Step for the Hydroxide Radicals: Boron Trifluoride Etherate/Sodium Iodide

A new efficient method for dealkylation of ethers is reported. Ethers could transform into corresponding alcohols with boron trifluoride etherate and sodium iodide in acetonitrile after hydrolysis. This reaction can proceed at room temperature, and the yield is excellent. It’s useful for deprotection process in organic synthesis.

Electrosynthesis and characterization of a polyfluorene derivative with green-light-emitting property

Green-light-emitting poly(diphenylmethylenefluorene) (PDPMF) was synthesized electrochemically by direct anodic oxidation of diphenylmethylenefluorene (DPMF) in dichloromethane (CH2Cl2) and boron trifluoride diethyl etherate (BFEE) binary solution. The oxidation potential of DPMF in this medium was measured to be only 0.78 V versus Ag/AgCl, which was lower than that determined in CH2Cl2 (1.0 V versus Ag/AgCl) or acetonitrile (ACN) (1.16 V versus Ag/AgCl) with 0.1 mol L−1 tetrabutylammonium tetrafluoroborate (Bu4NBF4) as the supporting electrolyte. The as-formed PDPMF films showed good electrochemical behavior and high thermal stability. Fluorescent spectra indicate that PDPMF is a good green-light-emitter with strong and bright green or yellow-green photoluminescence under 365 nm UV light.

Crystal structure and physical properties of lithium difluoro(oxalato)borate (LiDFOB or LiBF 2Ox)

The structural characterization and properties of lithium difluoro(oxalato)borate (LiDFOB) are reported. LiDFOB was synthesized as previously described in the literature via direct reaction of boron trifluoride diethyl etherate with lithium oxalate. The crystal structure of the salt was determined from single crystal X-ray diffraction yielding a highly symmetric orthorhombic structure ( Cmcm, a = 6.2623(8) Å, b = 11.4366(14) Å, c = 6.3002(7) Å, V = 451.22(9) Å 3, Z = 4 at 110 K). Single crystal X-ray diffraction of a dihydrate of LiDFOB yielded a monoclinic structure ( P2 1 /c, a = 9.5580(3) Å, b = 12.7162(4) Å, c = 5.4387(2) Å, V = 634.63(4) Å 3, Z = 4 at 110 K). Along with the crystal structures, additional structural information and the properties of LiDFOB (via 11B and 19F NMR, DSC, TGA and Raman spectroscopy) have been compared with those of LiBF 4 and LiBOB to better understand the differences between these lithium battery electrolyte salts.

Synthesis and properties of new polymeric surfactant with quaternary ammonium salt

The polymeric surfactant with quaternary ammonium salt (PQ) was synthesized by cationic ring-open polymerization using boron trifluoride diethyletherate as cationic catalyst. The chemical structure and aggregation behavior of PQ were studied by 1H NMR, surface tension, static light scattering, dynamic laser light scattering, electrical conductivity, and fluorescence measurement. The results show the surface tension (γcmc) and critical micelle concentration (cmc) of PQ decrease with increasing of sodium chloride concentration. The cmc and γcmc values of PQ measured by electrical conductivity and fluorescence measurements mainly identify with that obtained by surface tension measurements. The thermodynamic parameters ( $$ \Delta G_m^0 $$ , $$ \Delta H_m^0 $$ , $$ \Delta S_m^0 $$ ) from electrical conductivity indicated that the micellization of PQ was mainly the process of entropy-driven. In addition, the results from the viscosity stability between hydrolyzed polyacrylamide (HPAM) and PQ showed that the viscosities of mixed system for HPAM and PQ are higher than the viscosity of HPAM.

Synthesis of Imidazo[1,2-a]pyridines by the Bis(acetyloxy)(phenyl)-λ³-iodane-Mediated Oxidative Coupling of 2-Aminopyridines with β-Keto Esters and 1,3-Diones

Imidazo[1,2-a]pyridine-3-carboxylates can be prepared directly from 2-aminopyridines and β-keto esters by using bis(acetyloxy)(phenyl)-λ³-iodane as an oxidant and boron trifluoride etherate as a catalyst. The amount of catalyst plays a key role in determining the course of the reaction. Whereas the use of 0.2 equivalents of catalyst ensures the generation of imidazo[1,2-a]pyridines, raising the amount of catalyst to 1.0 equivalents results in exclusive α-acetoxylation of the β-keto esters. 2-Aminopyridines can also react with 1,3-diones to afford 3-acylimidazo[1,2-a]pyridines.

Modified Synthesis of 2-Ethoxycarbonyl-3-Trifluoromethyl-4-Methyl-Pyrrole Based on Barton-Zard Reaction and Its Porphyrin Derivative

In the synthesis of pyrrole 2-ethoxycarbonyl-3-trifluoromethyl-4-methylpyrrole(1) from 2-acetoxy-3-nitro-1,1,1-trifluorobutane(1b) and ethyl isocyanoacetate according to the Barton-Zard reaction,the organic base 1,8-diazabicyclo undec-7-ene(DBU) and the solvent tetrahydrofuran(THF) were replaced with K2CO3 and ethanol,respectively.The improved Barton-Zard procedure had advantages such as less expensive and safe reagents,higher yield and more convenient operation procedures than original Barton-Zard method.Moreover,the preparation of the intermediate 1b from compound 1a by acetylation reaction was carried out by employing acetyl chloride in boiling toluene solution instead of acetic anhydride and the catalyst concentrated sulfuric acid.Its optimum reaction conditions were that the molar ratio of acetyl chloride to compound 1a and reaction time were set as 1.2∶1 and 3～3.5 h,respectively.After treatment of compound 1 with excess LiAlH4 at low temperature,it affords the crude product α-(hydroxymethyl)-3-trifluoromethyl-4-methylpyrrole(1c),which immediately reacted via a tetramerization in the presence of the catalyst BF3·OEt2 and in CHCl3,followed by oxidation of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone(DDQ) to provide the corresponding trifluoromethylated porphyrin derivative 2.The results indicate that using boron trifluoride diethyl etherate(BF3·OEt2) as catalyst instead of p-toluenesulphonic acid(p-TsOH) in the synthesis of compound 2 from compound 1c can significantly increases the yield of product 2 up to 50% from 14%.

Polythiophene films on gold electrodes: a comparison of bulk and contact resistances in aqueous and organic media

Recently, developed technique for separated analysis of bulk and contact resistance was applied for the investigation of polythiophene films electropolymerized in boron trifluoride diethylether. Kinetics of polymer resistance and for the first time of the contact resistance during polymer oxidation and reduction were characterized. Influence of electrochemically controlled oxidation state on the polymer bulk and the polymer/metal contact resistance was measured in aqueous and organic environment. Variation of the electrical potential from −0.2 to 1.1 V vs. Ag/AgCl (sat) leads to an increase of the polymer conductivity for about three orders of magnitude and to a decrease of the contact resistance for about three orders of magnitude. The potential dependence of the two resistances was different, especially at high anodic potentials. In organic solution, the change of both resistances was more than six orders of magnitude. The results were compared with electrochemical and spectroelectrochemical data, a difference in the material behavior depending on the electrolyte solvent was observed. The influence of electrical potential on polymer resistance in aqueous solution was explained quantitatively by a three-state model with the values of oxidation potential +0.3 and +1.2 V.

Diversity-Oriented Synthesis of Functionalized Polyheterocycles from Garner Aldehyde

We report a diversity-oriented synthesis of diverse drug-like polyheterocycles from Garner aldehyde derived 1-hydroxy-1,3-dihydroisobenzofuran 20 as a key intermediate. The oxonium-mediated nucleophilic addition of 20 in the presence of boron trifluoride―diethyl ether complex provided enantiopure 1,3-disubstituted 1,3-dihydroisobenzofurans through 1,3-asymmetric induction. Further diversification of 20 allowed the diastereoselective syntheses of drug-like polyheterocycles including the 3-substituted isobenzofuran-1(3H)-one, 2,3-dihydro-1H-isoindol-1-one, and 3,4-disubstituted dihydroisoquinolinone ring systems.

On the Peculiarities of the Ring Contraction Reactions of Homodrimanes via Acid Mediated Epoxide Rearrangement

A selective rearrangement of a epoxy-homodrimanic substrate is described. Using fluorosulfonic acid at low temperature leads by ring contraction to a perhydrindanic structure. On the contrary, using boron trifluoride-diethyl ether at r.t. selectively brings about angular methyl migration.

ChemInform Abstract: Efficient Synthesis of 9‐Tosylaminofluorene Derivatives by Boron Trifluoride Etherate‐Catalyzed Aza‐Friedel—Crafts Reaction of in situ Generated N‐Tosylbenzaldimines.

An efficient and expeditious boron trifluoride etherate (BF 3 ·Et 2 O) catalyzed one-pot reaction for the synthesis of N-tosyl-9-aminofluorenes and anthracene derivatives from in situ generated N-tosylbenzaldimines via an aza-Friedal-Crafts reaction has been developed. The catalytic reaction shows high substrate tolerance with excellent yields.

Synthesis of tetrahydrobenzoisoquinolinols, tetrahydropyrindines, and hexahydroquinolines from 4-aryltetrahydropyridines

A straightforward synthesis of tetrahydrobenzoisoquinolinols 2, tetrahydropyrindines 3, and hexahydroquinolines 4 from versatile intermediate 6 is reported. Two key transformations were carried out by intramolecular Friedel–Crafts cyclization and ring-closing metathesis in moderate yields. Skeleton 6 was easily prepared from the known starting material 4-aryl-4-methoxypiperidin-3-ones 7 via Wittig olefination with Ph 3P=CHCO 2Et, deconjugation with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and boron trifluoride etherate (BF 3–OEt 2)-catalyzed addition of the corresponding iminium ion with allyltrimethylsilane.

ChemInform Abstract: Diaziridine Ring Expansion in 6‐Aryl‐1,5‐diazabicyclo[3.1.0]hexanes upon Reactions with Activated Olefins in Ionic Liquids.

AbstractReactions of activated trans‐olefins with azomethine imines, generated from diaziridines (I) on catalysis with boron trifluoride etherate in ionic liquids, are found to proceed with high regio‐ and stereoselectivity to afford diaziridine ring expansion products.

ChemInform Abstract: Novel Synthetic Methodologies. Part 207. An Efficient Synthesis of [(Tosylamino)alkyl]naphthalenols by Nucleophilic Addition of Naphthalen‐2‐ol with N‐Tosyl Imines Using Boron Trifluoride Etherate as Catalyst.

AbstractTitle reaction proceeds under mild reaction conditions and tolerates a range of functional groups like ether, halide, nitro or cyano groups.

A Mild and Highly Efficient Catalyst for Beckmann Rearrangement, BF3·OEt2

AbstractBF3·OEt2 (Boron trifluoride etherate), an inexpensive and commercially easily available Lewis acid stoichiometrically employed for Beckamann rearrangement in general, was now found to efficiently catalyze Beckmann rearrangement of ketoximes into their corresponding amides (up to 99% yield) in anhydrous acetonitrile under reflux temperature.

Reaction of 2-amino-5,5-bis(hydroxymethyl)-1-methyl-1,5-dihydro-4h-imidazol-4-one with aromatic aldehydes

The reaction of 5,5-bis(hydroxymethyl)creatinine with aromatic aldehydes in the boron trifluoride etherate results in 2-aryl derivatives of 2′-amino-3′-methyl-(1,3-dioxane)-5-spiro-4′-imidazolidin-5′-one.

Difluoro[2-(quinolin-2-yl)phenolato]borane

The title compound, C15H10BF2NO, was synthesized by the reaction of 2-(quinolin-2-yl)phenol and boron trifluoride etherate. The quinoline ring system and the benzene ring are twisted, making a dihedral angle of 8.3 (2)°. In the crystal, π–π inter­actions between the aromatic rings [centroid–centroid distance = 3.638 (9) Å] link the mol­ecules into chains propagating in [100].

ELECTROCHEMICAL POLYMERIZATION OF FLUORENE IN MIXED PROTON ELECTROLYTE OF ACETIC ACID CONTAINING BORON TRIFLUORIDE DIETHYL ETHERATE

Polyfluorene flims were synthesized electrochemically by direct anodic oxidation of fluorene in the mixed electrolyte of acetic acid and borontrifluoride diethyl etherate(BFEE)(5∶ 4 by volume).The oxidation potential of fluorine in the mixed electrolyte was measured to be only 0.48 V versus Pt,which was much lower than that determined in acetonitrile containing 0.1 mol L-1 tetrabutylammonium tetrafluoroborate(TBATFB).The conductivity of polyfluorene from this medium was 0.5 S cm-1,which was higher than that determined in pure BFEE(0.25 S cm-1).The polyfluorene films obtained from acetic acid and BFEE(5 ∶ 4 by volume) showed good electrochemical behavior and stability in concentrated sulfuric acid.FTIR,1H-NMR spectral results and theoretical studies demonstrated that the electropolymerization of fluorene mainly occurred at the 2,7-positions.Compared with that obtained from the mixed electrolyte without PEG1000,the polymer obtained from acetic acid and BFEE(5∶ 4 by volume) with PEG1000 showed a red shift in the fluorescence spectra,a better thermal stability and a more ordered stack of the platelet in appearance,but the thermal stability of the polymer obtained from acetic acid and BFEE(5∶ 4 by volume) was better than that for the one made in pure BFEE.At the same time,the fluorescence spectra results indicated that the soluble polyfluorene electrosynthesized from acetic acid and BFEE(5∶ 4 by volume) was a good blue light emitter which may find application in optoelectronics.