Amines tetrahydrofuran

The typical B-NMR signals of iminoboranes are essentially unaltered when iminoboranes are dissolved in liquids with Lewis base activity (e.g., tertiary amines, tetrahydrofuran) (19). I conclude that equilibria like Eq. (28) are shifted far to the left, even in the presence of an excess of the Lewis base D. 

The yttrium complex reacts with Lewis bases, like amines, tetrahydrofurane or phosphine oxides, but less readily with soft donors like phosphines, as monitored by NMR spectra. The triplet at —0.81 ppm collapses to a doublet at lower field, but no isolation of an adduct was possible, pointing out a weaker Lewis acidity for Y" in comparison to Sc. Alkyl- or alkylchloroaluminum compounds react with dimeric dicyclopentadienyl methyl yttrium to give di-ju-alkyl- or di-ju-chloro-bridged compounds as shown in eqs. (41) and (42). The chloro- and methyl-bridged complex (eq. 43) decomposes with formation of trimethyl aluminum and dicyclopentadienyl... 

Scheme 4.9 Aminoalkoxylation reactions to form 3-aminated tetrahydrofurane products.

Heating butanediol or tetrahydrofuran with ammonia or an amine in the presence of an acidic heterogeneous catalyst gives pyrroHdines (135,136). With a dehydrogenation catalyst, one or both of the hydroxyl groups are replaced by amino groups (137). 

Hexanitrostilbene may be prepared by a dding a solution of TNT ia tetrahydrofuran and methanol at 5°C to aqueous sodium hypochlorite. To this mixture a 20% solution of trimethyl amine hydrochloride is added at 5—15°C. Hexanitrostilbene precipitates, and is filtered and washed with methanol and... 

Aqueous mineral acids react with BF to yield the hydrates of BF or the hydroxyfluoroboric acids, fluoroboric acid, or boric acid. Solution in aqueous alkali gives the soluble salts of the hydroxyfluoroboric acids, fluoroboric acids, or boric acid. Boron trifluoride, slightly soluble in many organic solvents including saturated hydrocarbons (qv), halogenated hydrocarbons, and aromatic compounds, easily polymerizes unsaturated compounds such as butylenes (qv), styrene (qv), or vinyl esters, as well as easily cleaved cycHc molecules such as tetrahydrofuran (see Furan derivatives). Other molecules containing electron-donating atoms such as O, S, N, P, etc, eg, alcohols, acids, amines, phosphines, and ethers, may dissolve BF to produce soluble adducts. 

Articles fabricated from FEP resins can be made bondable by surface treatment with a solution of sodium in Hquid ammonia, or naphthalenyl sodium in tetrahydrofuran (64) to faciUtate subsequent wetting. Exposing the surface to corona discharge (65) or amines at elevated temperatures in an oxidizing atmosphere (66) also makes the resins bondable. Some of the more recent work is described in References 67—69. 

Diborane [19287-45-7] the first hydroborating agent studied, reacts sluggishly with olefins in the gas phase (14,15). In the presence of weak Lewis bases, eg, ethers and sulfides, it undergoes rapid reaction at room temperature or even below 0°C (16—18). The catalytic effect of these compounds on the hydroboration reaction is attributed to the formation of monomeric borane complexes from the borane dimer, eg, borane-tetrahydrofuran [14044-65-6] (1) or borane—dimethyl sulfide [13292-87-0] (2) (19—21). Stronger complexes formed by amines react with olefins at elevated temperatures (22—24). 

Many organic syntheses requHe the use of stericaHy hindered and less nucleophilic bases than //-butyUithium. Lithium diisopropylamide (LDA) and lithium hexamethyldisilazide (LHS) are often used (140—142). Both compounds are soluble in a wide variety of aprotic solvents. Presence of a Lewis base, most commonly tetrahydrofuran, is requHed for LDA solubdity in hydrocarbons. A 30% solution of LHS can be prepared in hexane. Although these compounds may be prepared by reaction of the amine with //-butyUithium in the approprite medium just prior to use, they are also available commercially in hydrocarbon or mixed hydrocarbon—THF solvents as 1.0—2.0 M solutions. 

Instmmental methods of analysis provide information about the specific composition and purity of the amines. QuaUtative information about the identity of the product (functional groups present) and quantitative analysis (amount of various components such as nitrile, amide, acid, and deterruination of unsaturation) can be obtained by infrared analysis. Gas chromatography (gc), with a Hquid phase of either Apiezon grease or Carbowax, and high performance Hquid chromatography (hplc), using siHca columns and solvent systems such as isooctane, methyl tert-huty ether, tetrahydrofuran, and methanol, are used for quantitative analysis of fatty amine mixtures. Nuclear magnetic resonance spectroscopy (nmr), both proton ( H) and carbon-13 ( C), which can be used for quaHtative and quantitative analysis, is an important method used to analyze fatty amines (8,81). 

Pyrrohdine [123-75-1] (tetrahydropyrrole) (19) is a water-soluble strong base with the usual properties of a secondary amine. An important synthesis of pyrrohdines is the reaction of reduced furans with excess amine or ammonia over an alumina catalyst in the vapor phase at 400°C. However, if labde substituents are present on the tetrahydrofurans, pyrroles may form (30). 

Borane complexes are the most widely used commercial boron compounds, after sodium borobydride. Examples used in organic synthesis are amine borane complexes and borane complexes of tetrahydrofuran and dimethyl sulfide. 

Heterocyclic Alcohols. Thek reactions with chloroformates lead to carbonates. Thus furan- and tetrahydrofuran-derived alcohols give the corresponding carbonates in 75% yield (15). Inorganic bases and tertiary amines as acid acceptors increase the rate and yield in this reaction. 

It resembles tetracyanoethylene in that it adds reagents such as hydrogen (31), sulfurous acid (31), and tetrahydrofuran (32) to the ends of the conjugated system of carbon atoms suffers displacement of one or two cyano groups by nucleophilic reagents such as amines (33) or sodiomalononittile (34) forms TT-complexes with aromatic compounds (35) and takes an electron from iodide ion, copper, or tertiary amines to form an anion radical (35,36). The anion radical has been isolated as salts of the formula (TCNQ) where is a metal or ammonium cation, and n = 1, 1.5, or 2. Some of these salts have... 

Aromatic amine-terminated poly(tetrahydrofuran) — 650 MW Amine chain extender —4,4 -methylene bis(3-chloro-2,6,-diethyl aniline) Note the amine chain extender must be melted into the polyol at 160°C for 3 hrs under stirring, until completely melted. Once cooled, the chain extender remains liquid in the polyol. 

Irradiation of the 2,1-benzisoxazoles in wet tetrahydrofuran or wet diethyl ether produces l/7-azepin-2(3//)-ones. whereas in an ethereal solution of a primary or secondary amine 3H-azepin-2-amines, e.g. 3. are formed.65... 

The carbanion 5, formed from V,V-diethyl-5-phenyl-3//-azepin-2-amine (4) with potassium amide in liquid ammonia, or with lithium 2,2,6,6-tetramethylpiperidide in tetrahydrofuran, is thiolated by dialkyl or diaryl disulfides to yield 3-(alkylsulfanyl)-3//-azepines, e.g. 6.38... 

Another example of reagent-induced asymmetric synthesis is the enantioselective preparation of phosphoramides 6 by addition of dialkylzine reagents to A-diphenylphosphinoylimincs 4 in the presence of the enantiomerically pure 1,2-amino alcohols 5a or 5 b (diethylzinc does not add to A-silyl- or A-phenylimines)12. Phosphoramides 6 (crystalline solids) are obtained in moderate to good yield and good enantioselectivity. The latter can be enhanced by recrystallization. Acidic hydrolysis with dilute 3 M hydrochloric acid/tetrahydrofuran provides the corresponding amines 7 without any racemization. 

Noell et al. reported the preparation of silica-poly(ether ether ketone) hybrid materials with improved physical properties.155 An amine-end-capped poly(ether ether ketone) was used to react with isocyanatopropyltriethoxysilane in tetrahydrofuran (THF). The triethylsilane-end-capped poly (ether ether ketone) was mixed with tetraethoxysilane (TEOS) in THF. Quantitative amounts of water were introduced into die system, and the mixture was reduxed at 80°C. The entire reaction mixture was allowed to further react in Tedon molds. Tough transparent materials were obtained by diis approach. 

Thermoplastic resins, self-reinforced, 26 Thermoplastics, preparation of, 257-258 Thermoplastic step-growth polymers, 3 Thermosetting polyester resins, 29-31 Thermosetting resins, 3-4, 19 Thermotropic compounds, 49 THF. See Tetrahydrofuran (THF) Thiobisphenol S (TBPS), 364 Thionyl chloride, 80 activation of, 111 3,3 -linked polymers, 480 Tin-amine coordination complex, 234 Tin compounds, 86, 232-233... 

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