Presence Of Boron Trifluoride Research Articles

1,1′‐Binaphthyl‐2‐methylpyridinium‐Based Peroxophosphotungstate Salts: Synthesis, Characterization, and Their Use as Oxidation Catalysts

AbstractA series of 1,1′‐binaphthyl‐2‐methylammonium and pyridinium salts 6, 7, and 8 was synthesized through the coupling reaction of 2‐(bromomethyl)‐1,1′‐binaphthalene (5) with the dendritic tetraallyl pyridinedicarbinol dendron 2 as well as triethylamine and 4‐tert‐butylpyridine. Tetraallyl pyridinedicarbinol dendron 2 was prepared by allylation of commercially available diethyl pyridine‐3,5‐dicarboxylate (1). The allylation of 2 with allyltrimethylsilane in the presence of boron trifluoride was unsuccessful, as tetraallyl pyridinedicarbinol trifluoroboron adduct 3 was obtained instead of expected hexaallylpyridine compound 4. The catalytic hydrogenation of allyl groups of the ammonium salt of 2, namely, tetraallyl 1,1′‐binaphthyl‐2‐methylpyridinium salt 6, successfully led to the corresponding tetra‐n‐propyl 1,1′‐binaphthyl‐2‐methylpyridinium salt 9. The reaction between salts 7, 8, and 9 and the heteropolyacid H3PW12O40 in the presence of a large excess of hydrogen peroxide afforded the corresponding 1,1′‐binaphthyl‐2‐methylammonium‐based polyoxometalate salts 10, 11, and 12, which contain a catalytically active trianionic [H3PW12O40]3– in the core. These binaphthyl–POM salts are soluble in commonly used organic solvents, and their IR and 31P NMR spectroscopic and elemental analysis data indicate the presence of the POM unit in the frameworks. These POM hybrids are efficient, recoverable, and reusable catalysts in the oxidation of thioanisole, cyclooctene, and cyclohexanol, with H2O2 as the oxidant. A study of the countercation effects indicated that the reaction kinetics and the selectivity are sensitive to the structure of the cation. Two cycles of catalytic reactions were performed without a discernible loss in activity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Particulate organic acids in the atmosphere of Italian cities: Are they environmentally relevant?

Mono- and dicarboxylic n-alkyl acids were extensively investigated in downtown Rome, Italy, and in Montelibretti, ∼30 km NE of the city, during 2005–2007. Congeners ranging from lauric to mellisic, and from succinic to α,ω-docosanedioic acids were evaluated as well as phthalic, palmitoleic and oleic acids, by solvent extraction of airborne particulates followed by derivatization with propanol in the presence of boron trifluoride, and gas chromatographic-mass spectrometric analysis. Shorter measurements were made in Milan, in Taranto, at suburban and rural sites of Italy, and in the polar regions, from 1996 to 2005. The predominance of palmitic and stearic acids observed elsewhere was confirmed, and the behaviour of azelaic and phthalic acids resulted strongly dependent upon the year season. In the urban sites, among the long-chain compounds, the lignoceric acid was usually the most abundant, while the cerotic, montanic and mellisic homologues cumulatively never exceeded 8% of the total. Unlike other contaminants, the concentrations of organic acids remained fairly invariant over the last decade, suggesting that more attention must be paid to them in the future.

Boron trifluoride-catalyzed degradation of poly- ɛ-caprolactone at ambient temperature

Poly- ɛ-caprolactone (PCL) can be accelerated to degrade in the presence of boron trifluoride at ambient temperature. The degradation behaviors were studied by using the inherent viscosity measurement, gel permeation chromatography (GPC), infrared analysis (FTIR), nuclear magnetic resonance analysis (NMR), and thermal analysis (DSC). With increasing the addition amount of boron trifluoride, the molecular weight of PCL decreases; the molecular weight distribution is broadened; and the degree of crystallinity of PCL increases at first at low BF 3 level, then decreases when BF 3 content exceeds to 2.64 wt%. The results of IR, 1HNMR and GPC reveal that ɛ-caprolactone monomer does not occur and the main degradation products are the oligomers of PCL with low molecular weight. The mechanism for boron trifluoride-catalyzed degradation of PCL is discussed.

Tandem molecular rearrangement in the alkylation of phenol with camphene

The alkylation of phenol with camphene in the presence of boron trifluoride in glacial acetic acid was accompanied by tandem molecular rearrangement with formation of a mixture of ortho- and para-substituted phenols having 1,7,7-trimethylbicyclo[2.2.1]hept-exo-2-yl and 5,5,6-trimethylbicyclo[2.2.1]hept-exo-2-yl substituents. The same products were obtained by rearrangement of 1,7,7-trimethylbicyclo[2.2.1]hept-exo-2-yloxybenzene under analogous conditions. Similar reactions performed in the presence of aluminum phenoxide as catalyst resulted in predominant formation of the corresponding ortho-substituted phenols.

A One‐Pot Asymmetric Sequential Amination‐Alkylation of Aldehydes: Expedient Synthesis of Aliphatic Chiral Amines

AbstractA one‐pot asymmetric sequential amination‐alkylation method has been developed for the synthesis of alkyl‐alkyl′ α‐chiral primary amines (aliphatic primary amines with a chiral center adjacent to the nitrogen atom) from aldehydes. In situ aldimine formation from non‐branched, α‐branched, and β‐branched aliphatic aldehydes with (R)‐ or (S)‐α‐(methylbenzyl)amine [catalyzed by 5 mol‐% Ti(OiPr)4] followed by reaction with a methyl, ethyl, or n‐butyl cuprate complex in the presence of boron trifluoride or an allyl Grignard reagent provides good yield (77–88 %) and diastereomeric excess (77–92 %) for amines 2 or 5. To further demonstrate the usefulness of this method, several of the secondary amine products (2d, 2e, and 5) were hydrogenolyzed, providing the corresponding enantioenriched alkyl‐alkyl′ α‐chiral primary amines 3d, 3e, and 6 (86–96 % yield).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Short Synthesis of 3‐Prenylcoumarins by an Unusual Prenylation

Prenylation of coumarins that have hydroxyl or alkoxyl or halo substitution (1a–1i) using 2‐methyl‐3‐butene‐2‐ol in the presence of boron trifluoride formed 3‐prenylcoumarins (2a–2d). Laila Impex communication no. 44.

Diastereoselective Synthesis of Chiral α‐Aminoorganotributyltins via Ring‐Opening of 2‐Tributylstannyloxazolidines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Synthesis of 1,1′‐Bishydroperoxydi(cycloalkyl) Peroxides by Homocoupling of 11—15‐Membered gem‐Bis(hydroperoxy)cycloalkanes in the Presence of Boron Trifluoride.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

One-pot fluoro-de-diazoniation of anilines in organic medium

Treatment of anilines with tert-butyl nitrite in the presence of boron trifluoride in ortho-dichlorobenzene leads to in situ fluoro-de-diazoniation and affords the corresponding fluoroaromatics with fair yields. This process, conducted in organic medium without Broensted acids, does not require isolation of hazardous diazonium salts and reduces the amounts of wastes. The results of the first screening are given.

Modification of poly(glycidyl methacrylate–divinylbenzene) porous microspheres with polyethylene glycol and their adsorption property of protein

Rigid porous poly(glycidyl methacrylate–divinylbenzene) (P(GMA–DVB)) microspheres were synthesized through suspension polymerization with a mixture of isooctane and 4-methyl-2-pentonal as the porogen. The microspheres were intended to use as column packing materials for protein separation. However, irreversible adsorption of protein was found on the polymer microsphere. To circumvent the problem, polyethylene glycol (PEG) was coupled to the microspheres. The coupling reaction took place between the hydroxyl group of PEG and the epoxy group of the P(GMA–DVB) solid medium in the presence of boron trifluoride. The density of PEG immobilized onto the P(GMA–DVB) can be determined easily by saponification of modified microsphere firstly and then titration of glycerol–PEG. The effect of the cross-linker content of microsphere on the density of PEG immobilization was investigated. Molecular weight of PEG was found to influence the PEG-immobilization density, which subsequently affects the hydrophilicity of the modified P(GMA–DVB). Bovine serum albumin (BSA) and trypsin were used as model proteins to examine the adsorption and desorption properties of the modified P(GMA–DVB) microspheres. The results demonstrated that P(GMA–DVB) porous microsphere with 20% DVB and modified with PEG4000 showed excellent adsorption and desorption properties. Adsorption capacity of BSA on the modified microsphere attained to 51.6 mg/g microsphere, and BSA mass recovery and trypsin activity recovery was up to 97.6% and 98.7%, respectively. The modified microsphere was demonstrated to be a promising hydrophobic interaction chromatography material for purification of protein.

Boron Trifluoride Mediated Prins Reaction of Methylene Diacetate with Styrenes. One-Pot Synthesis of 3-Chloro-3-arylpropanols

A one-pot procedure was developed for the synthesis of 3-chloro-3-arylpropanols, which are important starting materials for the synthesis of biologically active benzanilide derivatives. Styrenes were reacted with methylene diacetate in the presence of boron trifluoride to give the corresponding 3-chloro-3-arylpropanols in 36-84% yield by the Prins reaction. A strongly electron-donating methoxy substituent at either the ortho or para position of the styrene did not give the expected 3-chloro-3-arylpropanols due to polymerization. Styrene with a strongly electron-withdrawing nitro substituent gave the corresponding 3-chloro-3-arylpropanol in very low yield. Under the same reaction conditions, substituted norbornene gave a tricyclic ether. A very easy procedure for the synthesis of methylene diacetate is also reported.

Diastereoselective synthesis of chiral α-aminoorganotributyltins via ring-opening of 2-tributylstannyloxazolidines

Reactions of 2-tributylstannyloxazolidines 2a– d ( cis or trans), derived from ( R)-phenylglycinol protected as N-carbamate, with lithium diorganocuprates in presence of boron trifluoride in diethyl ether provide the corresponding functionalized tributylstannyl-α-aminoalcohols 3– 10 with diastereoselectivities close to 85:15 in favour of the ( S, R)-isomer. The stereochemical trend is preserved using allyltributyltin as nucleophile and TiCl 2(O i-Pr) 2 as Lewis acid in dichloromethane. The assignments of the ( S, R) or ( R, R) configurations in 3– 10 were achieved on the basis of physicochemical data combined with a radiocrystallographic structure. Stereochemical preferences were rationalized by consideration of the interactions occurring in the iminium intermediates.

Synthesis of [2,3- b]thieno- and furoquinoxalines by the [formula omitted] and [formula omitted] reactions of 2-substituted quinoxalines with acetophenones

The treatment of quinoxalin-2-one with acetophenones in the presence of boron trifluoride gives 3-(2-hydroxy-2-R-vinyl)-quinoxalin-2-ones, which can be transformed into [2,3- b ]thienoquinoxalines by reactions with P 2 S 5 .

A (1R,2R,5R)-(+)-2α-hydroxypinan-3-one ketimine

The title compound {systematic name: (1R,2R,5R)-(+)-2-hydr­oxy-2,6,6-trimethyl-3-[(3-pyrid­yl)methyl­imino]­bicyclo[3.1.1]­heptane}, C16H22N2O, was obtained by the condensation reaction of (1R,2R,5R)-(+)-2α-hydroxy­pinan-3-one with 3-(amino­meth­yl)pyridine in the presence of boron trifluoride. The compound was obtained as an enantiomerically pure isomer, and has the 1R,2R,5R configuration. In the crystal structure, mol­ecules are linked together by inter­molecular O—H⋯N hydrogen bonds between the hydr­oxy group of the pinanone group and the N atom of the pyridine ring, forming mol­ecular chains.

Preparation of α‐Substituted γ‐Alkoxyallylstannanes from β‐Tributylstannyl Acrolein Acetals: Scope of the Method and Primary Rationalization of the Obtained Results.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of 1,1′-bishydroperoxydi(cycloalkyl) peroxides by homocoupling of 11–15-membered gem-bis(hydroperoxy)cycloalkanes in the presence of boron trifluoride

A procedure was developed for the synthesis of 1,1′-bishydroperoxydi(C11-C15-cycloalkyl) peroxides based on homocoupling of geminal 11–15-membered bis(hydroperoxy)cycloalkanes in the presence of BF3⋅OEt2.

Highly fluorinated graphite prepared from graphite fluoride formed using BF 3 catalyst

Fluorinated graphites (CF 0.47) were obtained by reaction at room temperature of fluorine gas with graphite in the presence of boron trifluoride and hydrogen fluoride as catalysts. Their thermal treatments under fluorine at temperatures up to 600 °C lead to a progressive increase of the fluorine level resulting in an highly fluorinated graphite (CF 1.02). Whatever the fluorination level, a stage one fluorine–graphite intercalation compound is obtained. The sp 2 carbon hybridization is maintained for treatment temperature below 300 °C and two types of structure coexist for T T in the range 350–550 °C. Finally, above 550 °C, carbon hybridization is sp 3. The resulting materials were studied by 11B, 1H, and 19F NMR and EPR at different experimental temperatures giving informations about the intercalated fluoride species, the temperature of their removal from the host fluorocarbon matrix, as well as their mobility.

Preparation of α-substituted γ-alkoxyallylstannanes from β-tributylstannyl acrolein acetals: scope of the method and primary rationalization of the obtained results

α-Substituted γ-alkoxyallylstannanes were obtained from β-tributylstannyl acrolein acetals when reacted with lower order magnesium cyanocuprates in the presence of boron trifluoride at low temperature. In the case of n-alkylcyanocuprates an anti S N2′ substitution on a cisoid conformation appears to be the main reaction pathway. However, subtle competitions with other mechanisms may occur depending on the experimental conditions, on the reagents or on the substrates. These drawbacks constitute limitations for the use of the method especially when enantioenriched α-substituted γ-alkoxyallylstannanes are desired.

Grafting of Polystyrene onto Poly(butyl acrylate) and Polystyrene Backbones Using Functionalized Methacrylates

Summary: Grafting of terminal epoxide-functionalized polystyrene onto poly[styrene-co-(2-hydroxyethyl methacrylate)] or poly[(butyl acrylate)-co-(2-hydroxyethyl methacrylate)] backbones was carried out by coupling reactions catalyzed by boron trifluoride. The functionalized backbones were prepared by free radical copolymerization of 2-hydroxyethyl methacrylate (HEMA) with styrene or butyl acrylate. For the synthesis of terminal functionalized polymer chains a side reaction of the TEMPO-mediated free radical polymerization of methacrylates could be used successfully to convert TEMPO-terminated polymers into terminal epoxide-functionalized polymers by the use of glycidyl methacrylate. The number of epoxide units attached to the backbone was directly related to the TEMPO concentration during the disproportionation reaction. Taking P(S-co-HEMA) as well as P(BuA-co-HEMA) backbones in coupling reactions with different epoxy-functionalized polystyrenes in the presence of boron trifluoride, graft polymers with up to 7 and 37 side chains per backbone were produced. Molecular weight distribution curves of a linking experiment between P(BuA-co-HEMA) backbones and epoxide-functionalized polystyrene side chains.

Boron Difluoride -Diketonates: III. Boron Difluoride 3-Organylpenta-2,4-dionates

Boron difluoride 3-methyl-, 3-ethyl-, 3-propyl-, 3-isopropyl-, and 3-phenylacetylacetonates were synthesized by acylation of ketones with acetic anhydride, chelation of α-organyl-β-diketones, and reaction of acetylacetone with isopropanol in the presence of boron trifluoride. The resulting chelates were characterized by 1H NMR, IR, and UV spectroscopy.