N-butyllithium Research Articles

An Easy and Efficient Access to 2-Bromo-4-methoxyaniline

2-Bromo-4-methoxyaniline was obtained by treatment of 2,6-dibromo-4-methoxyaniline with n-butyllithium.

Synthese und charakterisierung von [formula omitted] bis(fluorenyl)komplexen des zirconiums und hafniums und deren anwendung bei der katalytischen olefinpolymerisation

The addition of n-butyl lithium to bis-biphenylene propene ( 1) or 1,4-bis-biphenylene butadiene ( 2) followed by the reaction with zirconium tetrachloride or hafnium tetrachloride leads to C 1- or C 2-bridged bis(fluorenyl) complexes of zirconium or hafnium containing substituents in the bridge. Complexes of the type (C 13H 8C(H)BuC 13H 8)MCl 2, (MZr ( 3), Hf ( 4)) are the first known examples of C 1-bridged bis(fluorenyl) complexes of a group 4 metal.

Syntheses of 1,2,5-benzotrichalcogenepins. Reactions of 1,3,2-benzodichalcogenastannoles with thiiranes

Three types of 1,2,5-benzotrichalcogenepins ( 3 and 4) containing sulfur and selenium were synthesized by reactions of the corresponding 2,2-dimethyl-1,3,2-benzodichalcogenastannoles ( 1) with thiiranes ( 2) using n-butyllithium.

Synthesis of [15N,15N‘]-N,N,N‘,N‘-Tetramethyl- ethylenediamine and Its Use in Solvation Studies of [6Li]-n-Butyllithium

Synthesis of [¹⁵N,¹⁵N‘]-<i>N</i>,<i>N</i>,<i>N‘</i>,<i>N‘</i>-Tetramethyl- ethylenediamine and Its Use in Solvation Studies of [⁶Li]-<i>n</i>-Butyllithium

Catalytic enantioselective deprotonation of meso-epoxides utilising homochiral bis-lithium amide bases

( R)-2-Cyclohexen-1-ol and ( R)-2-cyclooctene-1-ol have been prepared in very good ee using R, R-homochiral bis-lithium amide bases derived from homochiral C 2 symmetric diamines. ( R)-2-Cyclohexen-1-ol has been synthesized in good ee utilising catalytic homochiral bis-lithium amide in the presence of n-butyl lithium.

A novel method for the synthesis of chiral sulfonated phosphines

The selective and smooth introduction of sulfonate groups in chiral diphosphines by the reaction of hydroxy diphosphines with o-sulfobenzoic anhydride in the presence of Na 2CO 3 or n-butyl lithium, respectively, is described.

Synthesis and characterization of new silicon-containing fluoroacrylate monomers and polymers: 3

A series of new silicon-containing fluoroacrylate polymers and copolymers (with methyl acrylate) has been prepared, starting from 1,3-bis(hexafluoro-2-hydroxy-2-propyl)benzene (1,3-HFAB). The fluorinated, silicon-containing alcohol precursor was synthesized in two steps by reacting 1,3-HFAB first with n-butyl lithium and subsequently with dichlorodimethylsilane. The silicon-containing alcohol was finally reacted with acryloyl or methacryloyl chloride to give the corresponding monomers. Polymers were obtained by bulk free radical polymerization using α,α′-azobisisobutyronitrile as initiator. The polymers, which have inherent viscosities ranging from 0.20 to 0.33 dl g −1, form brittle hydrophobic films by solution casting. The polyacrylates are stable to about 375°C (10% weight loss) in nitrogen and exhibit glass transition from 67 to 110°C.

Chemical modification of polymers to improve flame retardance—II. The influence of silicon-containing groups

Polystyrene has been silylated by a two-stage process, involving reaction with n-butyl lithium in the presence of tetramethylethylenediamine, followed by reaction with trimethylchlorosilane, dichlorodimethylsilane or trichloromethylsilane. The degree of silylation can be increased if the polystyrene is initially brominated, in the presence of thallic acetate, prior to lithiation and silylation. The surfaces of poly(vinyl alcohol) films have also been modified with a number of chlorosilanes. Flame retardant effects of these modifications have been assessed by measurements of char yields, weight losses and limiting oxygen indices. The limiting oxygen indices of the silylated polymers are all significantly higher than those of the parent polymers and small char yields are obtained on combustion of them. Silicon is shown to have a greater effect on flame retardance in the presence of halogen for each of the modified polymers.

MoCl5/EtAlCl2-catalysed nonmetathesis polymerization of norbornadiene

Norbornadiene was polymerized, in moderate yield by MoCl5 or EtAlCl2. By using both components together, an increase in reaction rates and in polymer yields were observed. By the optimization of the reaction conditions, 100% of polymer yield was achieved. For comparison, the polymerization of the NBD was also accomplished by using initiators such as AlCl3, Et3Al, AZBN, and n-butyl lithium. All the obtained polymers gave similar IR and NMR spectra indicating the presence of the polynortricyclene structures. Though they show different molecular weight distribution, the solubilities of the polymers (obtained using MoCl5, AlCl3, EtAlCl2, and MoCl5/EtAlCl2) are very similar. DTA analyses show that the polymers (obtained by using MoCl5/EtAlCl2 pair or n-butyl lithium or Et3Al) have high thermal stabilities whereas all the other polymers are unstable in air. © 1996 John Wiley & Sons, Inc.

Kinetic study of anionic oligomerization of styrene by quantitative SEC

By the method of the absolute quantitative SEC, a process of anionic oligomerization of styrene, initiated by n-butyl lithium, was followed. The concentration of 1–5-mer monodisperse species in different reaction times can be obtained by HPSEC separation. The results showed that the propagation rate constants increased with increasing chain length and converged to a constant. © 1996 John Wiley & Sons, Inc.

Studies of lithium intercalation in 3R-WS 2

The lithium intercalation into the layered dichalcogenide 3R-WS 2 has been investigated by electrochemical reduction and by chemical reaction in n-butyl lithium solution. Essential results are (a) a charge transfer of nearly 0.6e −/W in Li x WS 2, (b) a small increase of the c-axis parameter of about 0.6%, and (c) a high mobility of the Li +-ions. The chemical diffusion coefficient of Li +-ions is estimated to be 8 × 10 −9 cm 2 s −1 in the composition range 0 ≤ x ≤ 0.25. The appearance of a structural transformation from 3R-WS 2 to 2H-Li x WS 2 is interpreted on grounds of instabilities in the interlayer structure.

Synthesis of racemic 2,4-dimethyltetradecanoic acid from Mycobacterium kansasii

A known intermediate, (3 R, S; 5 R, S)-3,5-dimethyl-6- triphenylmethyloxyhexanal gave, in a Wittig reaction with 1-octyltriphenylphosphonium bromide and n-butyl lithium in anhydrous tetrahydrofuran, a mixture of olefininic compounds. Trityl deprotection and hydrogenation of the double bond afforded the (2 R, S; 4 R, S)-2,4- dimethyltetradecanols. Oxidation of the alcohol functionality using pyridinium dichromate in anhydrous N, N′-dimethylformamide gave racemic, (2 R, S; 4 R, S)-2,4-dimethyltetradecanoic acids, which were converted to their methyl esters. 2,4-Dimethyltetradecanoic acids are constituents of glycolipid antigens from Mycobacterium kansasii.

Effects of lithium intercalation on the electronic properties of FePS3 single crystals.

The reaction of FePS3 single crystals with a 1.6M n-butyl lithium solution in n-hexane has been followed through de electrical conductivity measurements as a function of the intercalation time. In order to investigate the influence of lithium insertion on the FePS3 electronic properties we have also measured as a function of both temperature and intercalation time the de conductivity of equilibrated LixFePS3 single crystals. Upon lithium intercalation we have observed the following main effects: (i) an increase in the electrical conductivity, (ii) a simultaneous decrease in the activation energy, and (iii) a degenerate semiconductor behavior at the highest lithium content. In analogy to the LixNiPS3 systems, these results, discussed in terms of both the rigid band model and the so-called transition-metal weakly interacting one, seem to indicate that in the LixFePS3 complexes a new conduction mechanism appears at a different energy level from the beginning of the intercalation process with respect to the pure FePS3. Aiming at a better understanding of the still uncertain nature of reduction sites in the FePS3 lattice during lithium intercalation, we have also carried out Fourier transform infrared absorption measurements on single crystals of FePS3 and their lithium intercalation compounds at room temperature and in the frequency region from 800 to 3000 cm(-1). The results agree well with both the literature and the above conductivity data allowing a better identification of the lithium 2s electron accepting levels.

Synthesis and x-ray crystal structure of di-μ-(2,6-di- tert-butylphenoxo)di-lithium bis-dimethylsulphoxide solvate, C 32H 54Li 2O 4S 2. Comparison of the structure with other dimeric lithium alkoxides

Li(2,6- t Bu 2-OC 6H 3)(DMSO)} 2 was formed by the reaction of n-butyl lithium with 2,6-di- tert-butylphenol followed by recrystallization from toluene-DMSO solution. The single crystal X-ray diffraction data were collected at °C. The structural analysis showed that this phenoxide is a dimer and lithium metal is 3-coordinated. A special feature in this structure is the short OAr (ArC 6H 3-2,6- t Bu 2) bond length [1.315(13) Å] which is the shortest distance found in dimeric lithium phenoxides.

Synthesis and characterization of new alkoxide and aryloxide deriavatives of titanum and zirconium. X-ray molecular structure

Lithium or sodium alkoxides MOR (R CH2CHCMe2; M Li1; Na2; R C6F5; M Li3 were prepared by reaction of the alcohols with n-butyl lithium or sodium metal in hexane. Reaction of a hexane suspension of3 with SiClMe, afforded SiMe3(OC6F5)4, whereas the reaction of 3 equivalents of C6F5OH with AlMe3 in hexane led to Al(OC6F5)35. Compounds1 or2 react with one equivalent of [TiCp*Cl2Me] (Cp* C5Me5) in toluene to give [TiCp*ClMe(OCH2CHCMe2)]6. Complex6 reacts with AlEtCl2 to give quantitatively [TiCp*Cl3]. In the presence of water, the hydrolysis of6 takes palce giving the μ-oxo compound [{(TiCp*Cl)(μ − O)}3]. [TiCp*Cl2Me] reacted with an excess of the alcohol C6F5OH to give [TiCp*(OC6F5)3]7. [ZrCp2Cl2] reacted with two equivalents of pentaflurophenol in the presence of aniline to give the dialkoxide [ZrCp2(OC6F5)2]8. When the same reaction was carried out in a 1:1 molar ratio, a mixture of8 and the chloroalkoxide [ZrCp2Cl(OC6F5)]9 was obtained. A cleac reaction takes place when the μ-oxo compound [(ZrCp2Me)2(μ-O)] is treated with two equivalents of pentaflurophenol, leading to the isolation of the alkoxo complex [{ZrCp2(OC6F5)}2(μ-O)]10. The methylalkoxo derivative [ZrCp2Me(OC6F5)]11, was obtained by rection of [ZrCp2ClMe] with one equivalent of3. Alternative methods can be also be followed to synthesize8 and11. The crystal and molecular structure of8 has been determined by X-ray diffraction methods. The most interesting feature of this structure is the disposition of the (C6F5) ring planes, which are located practically on the reflection plane defined by O(1), Zr(1) and O(1)′.

Modelling studies of the controlled anionic copolymerization of butadiene and styrene

AbstractThe anionic polymerization of isoprene with n‐butyl lithium and polar modifier such as TMEDA and tripiperdinophosphine oxide were studied and kinetic and reactor models are proposed for these systems. Reactor conversion, molecular weight distribution and polymer glass transition temperature had been calculated from the model and compared favorably to the actual data for various combinations of reactor systems and operating conditions. Simulations of the model can be used to design reactor systems and predict polymer properties of large‐scale operations from results of small scale batch reactor runs.

The sonochemical barbier reaction applied to carboxylates. Study of a model case

Sonication of a n-butyl halide, lithium benzoate and lithium metal in THF at room temperature provides the expected ketone and/or benzil in yields depending on the nature of the halogen.

Evidence for bromine-lithium exchange in a local high concentration gradient

The product ratios for bromine-lithium exchange of 3,3′-dibromostilbene ( 6) with one equivalent of n-butyl lithium, s-butyl lithium or t-butyl lithium in THF and in Et 2O to give after quenching with methanol 3-bromostilbene ( 7) and stilbene ( 8), have been investigated. In the most reactive cases the ratio of 8:7 is significantly greater than expected for a statistical reaction. The apparently accelerated exchange of 7-Li relative to 6 is attributed to reaction in a high local concentration of the butyl lithium reagent.

Chemical and electrochemical intercalation of lithium into SnTiS 3 and BiTi 2S 5 misfit layer compounds

Lithium intercalation reactions into “SnTiS 3” and “BiTi 2S 5” misfit layer sulfides are studied. Chemical intercalation using n-buty llithium takes place by a monophasic mechanism inducing changes in the relative orientations of MS and TiS 2 sublattices. Extensive lithiation causes the loss of long-range ordering in the host lattice. This process occurs at a lower extent of intercalation for the 1:1:3 approximate composition. Electrochemical intercalation in lithium test batteries using “SnTiS 3” cathodes takes place by a biphasic mechanism in non-equilibrium conditions. The lithiated products increase the periodic length by ca. 0.5 Å Amorphization takes place in an extended plateau of the discharge curves above 0.75 F mol −1. For “BiTi 2S 5”, the complexity of the structure of the starting material, with extensive twinning in the BiS sublattice, leads to a more complicated pattern below 1 F mol −1. Three phases are involved in the process while the voltage decreases gradually: pristine “BiTi 2S 5”, a Stage I 17.3 Å li thiated phase and an intermediate 19.5 Å phase. A sharp decrease in voltage at 1 F mol −1 implies that the final product is Li(BiS) 1.14(TiS 2) 2. Further discharge results in the amorphization of this product in an extended plateau of the discharge curve.

PHOSPHORSUBSTITUIERTEN,N′ -DIMETHYLTHIOHARNSTOFFVERBINDUNGEN. IV. N,N′-DIMETHYLDIAZAPHOSPHETIDINTHIONE

Abstract In the reaction of N,N′-dimethyl thiourea, 1 with n-butyl lithium, followed by some dichlorophosphorus(III) compounds, in the presence of triethylamine the phosphadiazetidine thiones, 2-5 were obtained. In contrast to the analogous urea derivatives dynamic behavior was observed in the room temperature 1H and 13C n.m.r. spectra of 2-5. Oxidation reactions at the λ3P atom of 2 are described, involving as oxidizing agents bis(trimethylsilyl)peroxide (→6), elemental sulfur (→7), tetrachloro-o-benzoquinone (TOB) (→9), and phenyl azide (→10). An unusual reaction with hexafluoroacetone (HFA) was observed for the dimethylamino-substituted diazadiphosphetidine thione, 2: two molecules of HFA were oxidatively added to the λ3P atom, producing a perfluoropinacolyl ring system, while a further molecule of HFA was inserted into a PN bond of the diazadiphosphetidine thione ring system.