Showing papers on "Boron trifluoride published in 2019"

The Pictet–Spengler Reaction: A Powerful Strategy for the Synthesis of Heterocycles

Abstract: Ever since Ame Pictet and Theodor Spengler discovered their way to synthesize tetrahydroisoquinolines and β-carbolines, their method became a powerful methodology for the preparation of many natural products and pharmaceuticals. This method involves the reaction of arylethanamines and a carbonyl compound, such as aldehydes or ketones, under acidic medium. Trifluoroacetic acid and boron trifluoride etherate (BF3 ⋅ Et2O) are the common acidic catalysts employed in this reaction, although, sometimes organocatalysts and the chiral organophosphoric acids may catalyzed this reaction. In this chapter, the development of the Pictet–Spengler reaction is illustrated by the synthesis of various types of heterocyclic compounds.

Development of an intramolecular charge transfer-type colorimetric and fluorescence sensor for water by fusion with a juloidine structure and complexation with boron trifluoride

Abstract: An optical sensor with the ability to detect and determine water over a wide concentration range is highly desirable in the laboratory and industry. Here the sensitivity and spectral responses of an intramolecular charge transfer-type colorimetric and fluorescence sensor with β-carboline structure are tuned and improved significantly over various water contents in the organic solvent by fusion with an electron-donating juloidine structure and complexation with boron trifluoride (BF3). The sensors, ET-1 and ET-1-BF3, developed in this study can respond differently depending on water content. ET-1-BF3 releases BF3 to generate ET-1 by addition of a trace amount of water, and ET-1 forms hydrogen bonds with one water molecule in low water contents and a hydrogen-bonded proton transfer complex with several water molecules in high water contents, accompanying gradual color and fluorescence changes. This work shows a promising approach to the sensitive detection and precise determination of water over the whole concentration range using a simple and practical method with optical sensors.

Boron Trifluoride Etherate Promoted Microwave Assisted Synthesis of Antimalarial Acridones

Abstract: A microwave-assisted, rapid and efficient method using boron trifluoride etherate (BF3.Et2O) for the synthesis of acridones, via an intramolecular acylation of N-phenylanthranilic acid derivatives, has been developed. The reaction proceeds under solvent-free conditions, tolerates a wide range of functional groups, and provides rapid access to a range of acridones in good to excellent yields. Several of the synthesized acridones exhibited potent antimalarial activities against CQ sensitive and multi-drug resistant (MDR) parasites.

Synthesis and structure of novel Si-substituted silylpropyl derivatives of 2-mercaptobenzoxazole and 2-mercaptobenzothiazole

Abstract: A previously unknown carbofunctional (trimethoxysilyl)propyl derivative of the 2-mercaptobenzoxazole, C6H4NOCS(CH2)3Si(OMe)3, containing a tetracoordinated silicon atom was synthesized by nucleophilic substitution of the chlorine atom in the (3-chloropropyl)-trimethoxysilane with the benzoxazol-2-ylsulfanyl group. The reaction of 2-[(trimethoxysilyl)propylsulfanyl]benzoxazole or –benzothiazole with boron trifluoride etherate led to a previously unknown hydrolytically unstable Si-fluoropropyl derivatives of 2-mercaptobenzoxazole or 2-mercaptobenzothiazole, C6H4N(Y)CS(CH2)3SiF3 (Y = O, S). By transesterification of 2-[(trimethoxysilyl)-propylsulfanyl]benzoxazole by tris(2-hydroxyethyl)amine, a new silatranylpropyl derivative of 2-mercaptobenzoxazole containing an intramolecular coordination bond N→Si and a pentacoordinated silicon atom, C6H4NOCS(CH2)3Si(OCH2CH2)3N, was obtained.

Boron-Transition-Metal Triple-Bond FB≡MF2 Complexes.

Abstract: The boron–transition-metal triple-bond complexes FB≡MF2 (M= Ir, Os, Re, W, Ta) were trapped in excess solid neon and argon through metal atom reactions with boron trifluoride and identified by matrix isolation infrared spectroscopy and quantum chemical calculations. The FB≡MF2 molecule features very high 11B–F stretching frequencies at 1586.6 cm–1 (Ir), 1526.6 cm–1 (Os), 1505.5 cm–1 (Re), and 1453.2 cm–1 (W), respectively. The very high strength of B≡M bonds with triple-bonding character is confirmed by EDA-NOCV calculations and the active molecular orbital and NBO analysis. The experimental observation of FB stabilization by heavy transition-metal atoms with triple bonds opens the door to design new boron–transition-metal complexes.

On the Lewis Basicity of Phosphoramides: A Critical Examination of Their Donor Number through Comparison of Enthalpies of Adduct Formation with SbCl5 and BF3.

Abstract: The Lewis basicity of a series of phosphoryl compounds was examined using DFT and ab initio methods, including solvation effects. The enthalpies of adduct formation with two archetypal Lewis acids, antimony pentachloride and boron trifluoride, used to define the donor number DN and the BF3 affinity (BF3 A) respectively, were examined. The BF3 adducts allow the use of the high-accuracy G4 approach, whereas for SbCl5 adducts, three different DFT formalisms, including empirical dispersion corrections, were used because the G4 formalism is not available for third-row elements. For a comparison with experimental data, solvation effects were taken into account by using the polarizable continuum model. The experimental BF3 affinities were well reproduced by G4 calculations when including PCM solvation. Conversely, comparisons of our calculated values and experimental results reported in the literature show that SbCl5 enthalpies for phosphoramides are in error. In particular the DN for HMPA should be revised.

Three-Component Coupling of Aromatic Aldehydes, 1-Morpholino-2-nitroalkenes, and 3-Aminoazoles via Boron Trifluoride Etherate Catalysis: Reaction Pathway and Features of the Formation of Intermediates.

Abstract: 4,7-Dihydro-6-nitro-7-Ar-5-R-azolo[1,5-a]pyrimidines were obtained by the multicomponent reaction of aminoazoles, morpholino-nitroalkenes, and aromatic aldehydes in the catalysis of boron trifluoride etherate. The optimal reaction conditions were determined, and the formation of the target regioisomer was demonstrated. The pathway for multicomponent transformation, including the formation of azolyl-nitroalkene, was determined. Morpholino-nitroalkenes were assumed to convert into the corresponding nitroalkynes during catalysis of boron trifluoride etherate. For a multicomponent reaction with 4-nitrobenzaldehyde, conditions have been proposed that exclude the formation of a side regioisomer.

Boron trifluoride etherate in organic synthesis

Abstract: The innumerable applications of boron trifluoride etherate of boron trifluoride etherate in organic synthesi1,2 encouraged us to write a micro review on this reagent. The commercially available boron trifluoride etherate (b.p. 126oC), a brown liquid, is very toxic by inhalation, causes severe burns, reacts violently with water, hot alkali or alkaline earth (not Mg) metals with incandescence. It can be purified by distillation. This review would discuss only four principal use of boron trifluoride etherate: (a) hydroboration–oxidation reaction, (b) cleavage and rearrangement of epoxides, (c) esterification (d) cyclization. In addition, some other minor uses of boron trifluoride etherate will be briefly described.

Nano-cell-OBF2: an efficient and cheap catalyst for one-pot synthesis of pyrano[4,3-b]pyrans under mild and green condition

Abstract: Newly synthesized nano-cell-OBF2 catalyst was produced via boron trifluoride as lewis acid and nano cellulose as substrate. The obtained novel nanostructure has been assessed using Fourier transfor...

Comparative Study of Gas-Dynamic Processes in Inductively Coupled Argon–Hydrogen Plasma Containing Boron Trichloride and Boron Trifluoride

Abstract: A procedure for simulating gas-dynamic and thermal conditions during the conversion in a radiofrequency induction (RFI) plasma reactor has been developed. The model includes a turbulent flow of a mixture of ideal viscous compressible gases, taking into account inductive heating of the gas through heat conduction, convection, and radiation, considering the effect of the electromagnetic field force on the plasma motion. The formation of powder particles agrees with the results of thermodynamic calculations; the distribution of particles in the flow is described by the diffusion mechanism. The results of the simulation of the conversion of volatile boron chloride and boron fluoride in an RFI plasma torch with vortex-stabilized flow are presented.

The `super acid' BF3H2O stabilized by 1,4-dioxane: new preparative aspects and the crystal structure of BF3H2O·C4H8O2

Abstract: Highly Bronsted-acidic boron trifluoride monohydrate, a widely used `super acid-catalyst', is a colourless fuming liquid that releases BF3 at room temperature. Com­pared to the liquid com­ponents, i.e. boron trifluoride monohydrate and 1,4-dioxane, their 1:1 adduct, BF3H2O·C4H8O2, is a solid with pronounced thermal stability (m.p. 401–403 K). The crystal structure of the long-time-stable easy-to-handle and weighable com­pound is reported along with new preparative aspects and the results of 1H, 11B, 13C and 19F spectroscopic investigations, particularly documenting its high Bronsted acidity in aceto­nitrile solution. The remarkable stability of solid BF3H2O·C4H8O2 is attributed to the chain structure established by O—H⋯O hydrogen bonds of exceptional strength {O2⋯H1—O1 [O⋯O = 2.534 (3) A] and O1—H1⋯O3i [2.539 (3) A] in the concatenating unit >O2⋯H1—O1—H2⋯O3i<}, taking into account the mol­ecular (non-ionic) character of the structural moieties. Indirectly, this structural feature documents the outstanding acidification of the H2O mol­ecule bound to BF3 and reflects the super acid nature of BF3H2O. In detail, the C22(7) zigzag chain system of hydrogen bonding in the title structure is characterized by the double hydrogen-bond donor and double (κO,κO′) hydrogen-bond acceptor functionality of the aqua ligand and dioxane molecule, respectively, the almost equal strength of both hydrogen bonds, the approximatety linear arrangement of the dioxane O atoms and the two neighbouring water O atoms. Furthermore, the approximately planar arrangement of B, F and O atoms in sheets perpendicular to the c axis of the ortho­rhom­bic unit cell is a characteristic structural feature.

Direct Synthesis of Phosphonates and α-Amino-phosphonates from 1,3-Benzoxazines

Abstract: A straightforward and novel method for transformation of readily available 1,3-benzoxazines to secondary phosphonates and α-aminophosphonates using boron trifluoride etherate as catalyst is developed. The formation of phosphonates proceeds through ortho-quinone methide (o-QM) generated in situ, followed by a phospha-Michael addition reaction. On the other hand, the α-aminophosphonates were obtained by iminium ion formation and the subsequence nucleophilic substitution of alkylphosphites. This method can be also used for the preparation of o-hydroxybenzyl ethers through oxa-Michael addition.

Monohydrater cefotiam hydrochloride compound and pharmaceutical composition thereof

Abstract: The invention discloses a monohydrate cefotiam hydrochloride compound and a preparing method thereof. One mole of cefotiam hydrochloride contains one mole of water, and an x-ray diffraction spectrogram of the compound has characteristic peaks at the positions with the diffraction angles 2theta of 14.82-15.22 degrees, 29.92-30.32 degrees, 31.48-31.88 degrees, 35.01-35.41 degrees and 37.79-38.19 degrees. 7-amino-cephalosporanic acid (7ACA) serving as a starting material is condensed with 1-(2-dimethylaminoethyl)-5-thiotetrazole under the catalytic effect of organic solvents dimethyl carbonate boron trifluoride and the like to prepare an intermediate at a C-3 site; then 2-(2-aminothiazol-4-yl) acetic acid hydrochloride reacts with methylene chloride and concentrated hydrochloric acid gas to prepare acyl chloride at a 7 site, and the one-water cefotiam hydrochloride compound is synthesized. The operation is simple and environmentally friendly, the reactants are easily obtained, the reaction conditions are mild, and the yield is high. The one-water cefotiam hydrochloride compound has low hygroscopicity and impurity content, good fluidity and thermodynamic stability and wider applicationprospects.

Lewis Acid-Mediated Cyclization of Allenyl Aryl Ketones.

Abstract: The cyclization of a series of nonheterocyclic allenyl aryl ketones was examined using boron trifluoride etherate and indium triflate to mediate the reaction. Yields with BF3 were low in most instances due mainly to competitive destruction of the substrates. With In(OTf)3, there was less decomposition, and the yields of the cyclized product were much higher, but only for substrates with electron-donating substituents. Cyclization did not occur without those substituents. A computational study using the ωB97X-D/6-311+G(2d,p)//ωB97X-D/6-31+G(d,p) method confirmed better stability of the σ-complexed substrate by indium(III) and that meta-substituents on the phenyl ring of the substrate significantly influenced the activation barrier of the cyclization, whereas the effect of para-substituents was almost negligible. The computational results supported the idea that the cyclization is a 4π-electrocyclization and not a 5-endo-dig ring closure as had been proposed in the literature.

A New Alkylation of Aryl Alcohols by Boron Trifluoride Etherate.

Abstract: The ethylation of aryl alcohols by an ethyl moiety of boron trifluoride etherate is described. The reaction proceeded cleanly and afforded good yields of the corresponding aryl ethyl ethers. It tolerated the presence of functional groups such as aryl, alkyl, halogens, nitro, nitrile, and amino. However, the presence of amino or nitro groups ortho to a hydroxyl group of an aryl compound drastically reduced the yields of the anticipated products due to the chelation of the aforementioned functional groups with boron trifluoride etherate. A nitrogen atom in the aromatic ring system, as exemplified by hydroxypyridine and 8-hydroxyquinoline, completely inhibited the reaction. Resorcinol, hydroquinone, and aryl alcohols with aldehyde functions decomposed under the reaction conditions.

Method for synthesizing progesterone

Abstract: The invention belongs to the technical field of preparation processes of steroid hormone drugs, and particularly relates to a method for synthesizing progestational hormone drug progesterone. The method uses a compound represented by a formula (II) as a raw material, and firstly the compound shown in the formula (II) is reacted with a boron trifluoride diethyl ether in pure benzene to obtain a compound shown in a formula (III); the compound of the formula (III) is reacted with potassium permanganate or sodium periodate in acetone to obtain crude progesterone in a formula (I), and the crude progesterone is refined with ethanol to obtain the progesterone. The method fundamentally changes a synthetic route, adopts cheap starting materials, reduces reaction steps, and is simpler, economical and environmentally friendly, the total yield of the synthesis is above 80%, the HPLC content is above 99.35%, and the method is favorable for industrialization implementation and improves economic benefits.

Boron neutron capture therapy system

Abstract: The invention discloses a boron neutron capture therapy system, which comprises a boron neutron capture therapy device and a like [alpha]-amino acid boron trifluoride compound, wherein the structure of the like [alpha]-amino acid boron trifluoride compound is shown as formula (I) (as shown in the Description), wherein R represents hydrogen, methyl, isopropyl, 1-methyl propyl, 2-methyl propyl, hydroxymethyl, 1-hydroxyethyl, benzyl or hydroxybenzyl, and M is either H or a metal atom; and energy, which is generated after a neutron beam generated from the boron neutron capture therapy device acts on the like [alpha]-amino acid boron trifluoride compound, can damage tumor cell DNA.

BORON NEUTRON CAPTURE THERAPY SYSTEM AND USE OF α-AMINO ACID-LIKE BORON TRIFLUORIDE COMPOUND IN PREPARATION OF MEDICAMENT FOR TUMOR THERAPY

Abstract: Wherein: R is selected from hydrogen, methyl, isopropyl, 1-methylpropyl, 2-methylpropyl, hydroxymethyl, 1-hydroxyethyl, benzyl or hydroxybenzyl; M is H or metal atom. The energy generated from the action of the neutron beam generated by the boron neutron capture therapy device on the α-amino acid-like boron trifluoride compound destroys tumor cell DNA. In another aspect, the present disclosure discloses a use of an α-amino acid-like boron trifluoride compound in the preparation of a medicament for tumor therapy.

Preparation method of lithium tetrafluoroborate crystalline particles

Abstract: The invention relates to the field of preparation of lithium tetrafluoroborate and more particularly relates to a preparation method of lithium tetrafluoroborate crystalline particles. The preparationmethod at least comprises the following steps: (1) preparing a solution mixing boron trifluoride and lithium fluoride in a first solvent and reacting to prepare a lithium tetrafluoroborate solution;(2) controlling the temperature and distilling: adding the lithium tetrafluoroborate solution into a second solvent and carrying out normal-pressure distillation and/or vacuum distillation; filteringand decompressing and drying an obtained filter cake to obtain the lithium tetrafluoroborate crystalline particles, wherein the distillation temperature is 20 to 80 DEG C, the distillation time is 2 to 12h and the volume ratio of the first solvent to the second solvent is 1 to (1 to 10).

Preparation and application of beta-diketone boron fluoride fluorescent dye adopting first-class coumarin as framework

Abstract: The invention discloses synthesis of a beta-diketone boron fluoride fluorescent dye adopting dicoumarin as a framework. The structural general formula of the beta-diketone boron fluoride fluorescent dye is shown as a formula I or a formula II. Through the design, a series of coumarin with substituents introduced from three positions is prepared, then Claisen condensation is conducted on coumarin-containing ester and a corresponding carbonyl compound to obtain a series of compounds of beta-diketo acid ligands, the length of conjugated chains is increased, and the emission wavelength of the conjugated chains is improved. Finally, the beta-diketo acid ligands are subjected to a coordination reaction with boron under the action of boron trifluoride diethyl ether to form a series of the beta-diketone boron fluoride fluorescent dye based on coumarin. The method has the advantages that the synthesis steps of raw materials are simple, the yield is high, and the method is simple and easy to implement. The fluorescent dye has a narrow ultraviolet absorption visible spectrum, a narrow fluorescence emission spectrum and long absorption emission waves and is stable in optical property; the dyecan be used for cell imaging, fluorescent probes and the like and has a broad application prospect in the fields of chemical sensing, biological labeling, biological imaging, organic light emitting diodes (OLED), photoelectric materials, fluorescent probes and the like. In the formula I, R1, R2, R3 and R4 refer to alkyl groups with the carbon number smaller than 20.

Method for synthesizing di-tert-butylphenylphosphonium tetrafluoroborate

Abstract: The invention discloses a method for synthesizing di-tert-butylphenylphosphonium tetrafluoroborate, and belongs to the field of organic synthesis. The method comprises the following steps: in the anhydrous and anaerobic atmospheres, taking dichlorophenylphosphine as a raw material, after the reduction of diisobutyl aluminium hydride, reacting with tertiary butanol under the catalytic action of boron trifluoride, and then carrying out hydrolysis to generate the di-tert-butylphenylphosphonium tetrafluoroborate. Compared with the prior art, the method is high in yield and simple in aftertreatment, and is more applicable for industrial production.

Method for synthesizing 3-iodine-N-protected-L-tyrosine methyl ester through de-MOM-protection

Abstract: The invention discloses a method for synthesizing 3-iodine-N-protected-L-tyrosine methyl ester through de-MOM-protection and belongs to the technical field of organic synthesis. N-protected-L-tyrosinemethyl ester is reacted with MOMCl and iodine reagent to give 3-iodine-N-protected-O-methyl methyl ether-L-tyrosine methyl ester, normal-pressure de-MOM-protection is performed in hydrogen atmosphereunder palladium catalysis to obtain 3-iodine-N-protected-L-tyrosine methyl ester. The method for removing the MOM protecting group adopted by the invention avoids the group tolerance problem in the conventional strong acid system such as hydrochloric acid, acetic acid, trifluoroacetic acid or boron trifluoride ether, and has high reaction selectivity and simple post-treatment.

Preparing method of ceftiazole

Abstract: The invention provides a preparing method of ceftiazole. The method is characterized in that after the condensation reaction of 7-aminocephalosporanic acid and 1-(2-dimethylaminoethyl)-1H-5-tetrazole-thione is catalyzed through a boron trifluoride complex with dimethyl carbonate as the solvent, crystal separation is not conducted, cefotiam is condensed with pure water as the reaction solvent and aminothiazolacetyl chloride hydrochloride, acidification and crystallization are conducted on the cefotiam through hydrochloric acid, and the ceftiazole is obtained. Solvents applied in the method canall be recycled, the environmental protection pressure is greatly reduced, the environmental pollution is low, cost is reduced, and meanwhile the indexes of the ceftiazole are improved.

Preparation method of capecitabine impurity G

Abstract: A preparation method of a capecitabine impurity G comprises the following steps: one, reacting the compound shown by a formula I with trichloroacetonitrile in the presence of DBU, and executing distillation under reduced pressure to obtain a target product light yellow oily compound shown by a formula II; two, adding boron trifluoride diethyl etherate into the compound of the formula II and capecitabine API in the presence of anhydrous copper sulfate, executing heating to a certain temperature under the protection of nitrogen, executing reaction, adding potassium carbonate, and extracting reduced-pressure distillation and purification to obtain a target product light yellow solid compound shown by a formula III; three, dissolving the compound shown by the formula III in methanol, adding dilute acid, concentrating under reduced pressure, and executing purification to obtain the target product anhydrous oily substance capecitabine impurity G. (shown in the description).

Industrial production method of boron-10 isotope

Abstract: The invention provides an industrial production method of a boron-10 isotope and belongs to the field of chemical synthesis and separation. The industrial production method is invented mainly for solving the problem that boron-10 isotope cannot be continuously and stably produced at present. Methyl ether is pressurized to become liquid, a molecular sieve is used for adsorbing the methyl ether liquid, boron trifluoride gas is rectified by a low-temperature rectifying column and then comes out of a column top, and the methyl ether and the boron trifluoride are subjected to complexation reactionin a complexation reactor. The generated complex enters an exchange reaction distillation column. By heating the complex through a reboiler, the complex is heated to a temperature for decomposition, vapor is completely condensed as a liquid to reform a boron trifluoride-methyl ether complex, the refluxing liquid and the vapor are in convective contact for chemical exchange reaction to enable borontrifluoride-10 to enter a liquid phase from a gas phase successively and enter a column kettle with the downward flowing liquid, and the complex of boron trifluoride-11 is also continuously subjectedto exchange reaction and is transferred from the liquid phase to the gas phase to the top of the column. The industrial production method has the advantage of continuous and stable production.

Preparation method and solid fluorescent application based on planar chiral [2.2] cyclophane BODIPY molecules

Abstract: The invention belongs to the technical field of chiral dyes, and discloses a preparation method and an application of novel planar chiral BODIPY. In argon atmosphere, planar chiral 4-[2.2] cyclophaneformaldehyde, a pyrrole derivative, trifluoroacetic acid and solvents are placed into a three-mouth reaction flask, and reaction is performed at room temperature for 3-6 hours. Under the condition ofice-water bath cooling, DDQ (2, 3-dichloro-5, 6-dicyan p-benzoquinone) is added, the temperature rises up again slowly to reach the room temperature, and stirring reaction is performed for 1-2 hours.Triethylamine and boron trifluoride diethyl etherate are added, and stirring reaction is continued at the room temperature for 5-8 hours. Reaction solution is washed with diluted hydrochloric acid, washed with water and extracted by dichloromethane, organic phases are combined, and the reaction solution is dried by anhydrous magnesium sulfate. Column chromatography is performed to obtain planar chiral BODIPY products BP-1 and BP-2. Dichloromethane solution of the BP-1 is slowly volatilized to obtain crystals of BP-1 molecules. A novel planar chiral BODIPY dye is synthesized, a crystal structure of the dye is obtained, and the dye can be used as a solid fluorescent dye.