Anhydrous Tetrahydrofuran Research Articles

The extraction and determination of free lithium in LiB alloys

Extraction of the lithium phase from lithium-rich LiB alloys was achieved by reaction of the alloy with dry naphthalene dissolved in anhydrous tetrahydrofuran. The resulting radical anion was hydrolyzed and the lithium was determined by potentiometric titration from the moles of hydroxide formed. The composition of the Li x B y residue was determined by difference.

Synthesis of Methyl 4-Isopropyl-7-methyl-5, 7-octadienoate

Synthesis of methyl 4-isopropyl-7-methyl-5, 7-octadienoate (4) from readily available starting materials are described. Method A : Methyl 4-formyl-5-methylhexanoate (2) was prepared from the reaction of the piperidine enamine of isovaleraldehyde and methyl acrylate. A Wittig reaction between (2) and methallyli denetriphenylphosphorane in anhydrous tetrahydrofuran gave predominantly compound (4). Method B : A Wittig reaction of between 4-cyano-2-isopropyl butyraldehyde (3) and methallylidene-triphenylphosphorane gave 4-isopropyl-7-methyl-5, 7 - octadienenitrile (5). Hydrolysis of (5) under basic conditions gave a mixture of (4) and isomers of (4).

13C‐NMR. Spectra, Structure and Reactivity of Cyclic Oxocarbons

AbstractThe structures of cyclic polyketones, their hydrates and reduction products were studied in different solvents by 13C‐NMR. spectroscopy. In dimethylsulfoxide solution rhodizonic acid (1), croconic acid (2) and squaric acid (3) exhibit signal averaging. In anhydrous tetrahydrofuran 1 and 2 could be observed as non‐dynamic species. The spontaneous reactions of dodecahydroxycyclohexane (5) and decahydroxycyclopentane (‘leuconic acid’) (6) and the sequence of formation of ring‐contracted products were investigated. Key intermediates could be clearly identified which support the mechanism proposed earlier involving a benzylic acid type rearrangement followed by decarboxylation and subsequent redox reactions.

Cyclization of diethyl 2-acetoacetyl-3-oxoglutarate anion generated in situ by the reaction of diethyl sodio-3-oxoglutarate with diketen

Reaction of diethyl sodio-3-oxoglutarate with diketen (4-methyleneoxetan-2-one) in anhydrous tetrahydrofuran under mild conditions provided an intermediate adduct (diethyl 2-acetoacetyl-3-oxoglutarate anion)(2), which immediately cyclized to a γ-pyrone (ethyl 3-ethoxycarbonyl-6-methyl-4-oxo-4H-pyran-2-ylacetate)(3), regarded as a masked form of tetra-acetic acid (3,5,7-trioxo-octanoic acid)(1), and three aldol-type condensation products [ethyl 2-ethoxycarbonyl-3,5-dihydroxyphenylacetate (4), diethyl 2,6-dihydroxy-4-methylisophthalate (5), and ethyl 3-acetyl-2,6-dihydroxy-4-methylbenzoate (6)].

Azole chemistry : XI. 3-Dimethylsila-2 H-imidazo[1,2- a]benzimidazoles

2-Aminobenzimidazole, and its 5,6-dichloro, 5,6-dimethyl, and 5,6-dinitro derivatives react with bromomethyldimethylchlorosilane in anhydrous tetrahydrofuran at room temperature to give the new heterocycles, 3-dimethylsila-2 H-imidazo [1,2- a]benzimidazoles, in good yields. The spectral properties of these heterocycles are discussed.

Bromine Addition Reaction to Olefins with Magnesium Bromide and Aroyl Peroxides

Abstract When MgBr2 prepared in anhydrous tetrahydrofuran was added to a mixture of olefin and benzoyl peroxide, the peroxide decomposed at a moderate rate at room temperature. Olefin dibromide and magnesium benzoate were obtained in nearly quantitative yields. The effects of p- and m-substituents of peroxide and of the structure of olefin were studied. A complex consisting of MgBr2 and peroxide was formed. Abstraction of brominium cation from the complex by the olefinic double bond was proposed.

2-Amino-alcohols from α-amino-acids: a single-step mild procedure

α-Amino-acids are reduced by diborane in anhydrous tetrahydrofuran to 2-amino-alcohols. Substituted halogenophenylalanines are reduced in good yield without hydrogenolysis of the halogen–carbon bond.

Formation of p-carborane(12) from mo-carborane(12) via the cobalt complex [( o-C 2B 10H 12) 2Co III] -

Oxidation of the cobalt complex obtained from o-C 2B 10H 12 2- and CoCl 2 in anhydrous tetrahydrofuran (THF) leads to a mixture of o-, p- and m-carborane(12) isomers whose ratio depends on the temperature (within the range 25–150°) and the length of heating. Similar mixtures of isomers have been obtained from the oxidation of p-C 2B 10H 12 2- and m-C 2B 10H 12 2- respectively and CoCl 2 in anhydrous THF. It is suggested that the presence of the cobalt atom in the complex reduces the activation energy required for the isomerization which is not observed with uncomplexed C 2B 10H 12 2- anions even at temperatures as high as 150°. A mechanism is proposed to explain the function of the cobalt atom in this process.

Preparation of α-diazo-β-disulphones; a novel sulphinate elimination in their coupling reactions

Bisarylsulphonyldiazomethanes are most conveniently prepared by the addition of a bisarylsulphonylmethane in aqueous ethanol containing 1 equiv. of sodium hydroxide to 3 mol. equiv. of toluene-p-sulphonyl azide. The reverse order of addition, with equimolar amounts of reactants as suggested by Klages and Bott, is unsatisfactory, since under these conditions the first-formed diazodisulphone undergoes secondary reactions, a major product of which is the bisarylsulphonyiformaldehyde hydrazone (XI). In anhydrous tetrahydrofuran, α-diazo-β-disulphones react with 2 mol. Equiv, of the sodium salt of a β-disulphone to provide a vinylhydrazone and sodium arenesulphinate. The latter must arise exclusively from the carbanion since interaction of bisphenylsulphonyldiazomethane (V; Ar = Ph) and the carbanion from the 2,4-xylyl disulphone (II; Ar = 2,4-xylyl) yields exclusively sodium 2,4-xylenesulphinate whilst a similar reaction between bis 2,4-xylylsulphonyldiazomethane and the carbanion from the phenyl disulphone (II; Ar = Ph) provides only sodium benzenesulphinate. In contrast, sulphinate elimination occurs from the diazo-compound when it is coupled with a carbanion containing carbonyl rather than sulphonyl groups. The mechanism of the reactions is discussed.

Novel rearrangement of αα-dichlorodibenzyl sulphides. A new synthesis of acetylenes

αα-Dichlorodibenzyl sulphides are converted directly into diarylacetylenes by reaction with triphenylphosphine and potassium t-butoxide in anhydrous tetrahydrofuran.

Nature of the mixed hydrides between aluminum chloride and lithium aluminum hydride in anhydrous tetrahydrofuran

The concentration dependence of the specific conductivity of aluminum chloride, chloroderivatives of aluminum hydride and lithium aluminum hydride in tetrahydrofuran were measured. Two types of the conductivity-concentration curve were obtained; the one is linear and the other is concave upward, which may be due to a disproportionate ionization process and due to a variation in the association number with a change in concentration, respectively. The reaction of aluminum chloride with lithium aluminum hydride is also investigated by the conductivity method. The formation of the species AlHCl 2 and AlH 2Cl and of ionized complex Li +AlHCl 3 − and Li +AlH 2Cl 2 − in tetrahydrofuran is proposed to account for the maxima in the conductivity curves. The formation of the complex in diethyl ether is also briefly discussed.

Dinitrogen complexes of osmium(II)

A series of 12 dinitrogen complexes of osmium(II), mer-[OsX2(N2)(QR3)3](X = Cl or Br; QR3= tertiary phosphine or arsine) has been prepared by the zinc reduction under dinitrogen of solutions of mer-[OsX3(QR3)3] in anhydrous tetrahydrofuran (THF). The compounds are assigned the meridional configuration with dinitrogen trans to halogen on the basis of their n.m.r. and i.r. spectra. The co-ordinated dinitrogen is displaced quantitatively by diphosphine Ph2P·CH2·CH2·PPh2 or by halide ion in the presence of air. Attempts to prepare an analogous series of complexes of ruthenium(II) were unsuccessful.

Complexes of Bis(cyclopentadienyl)titanium(III) chloride with some bidentate ligands

Bis(cyclopentadienyl)titanium(111) chloride (cp2TiCl) complexes with 1,l0-phenanthroline (phen), 2,2?-dipyridyl (dipy), o-phenylenediamine (phm), and α-picolylamine (picam) in anhydrous tetrahydrofuran to give cp2TiCl,1.5L where L is the bidentate ligand. In air-free water all showed the conductivity of 1 : 1 electrolytes, but were insoluble in the common organic solvents.

Organometallic acetylene chemistry : I. tetraethynylsilane, tetraethynylgermane and some substituted ethynyl organogermanes

Several new group IV organometallic acetylides have been synthesized utilizing the reaction of sodium acetylide with organometallic halides in anhydrous tetrahydrofuran. The expected mono-, di- and tetraethynyl derivatives were obtained. In addition, a number of disubstituted organometallic acetylides and polymeric residues were obtained. The nature of the reaction products leads one to the assumption that under the selected conditions monosodium acetylide disproportionates slowly into disodium acetylide. At least one of the products is highly explosive.

Tritium-Labeled Compounds IV. d-Glucose-6-t, d-Xylose-5-t, and d-Mannitol-1-t.

Methods are presented for the preparation of d-glucose-6-t, d-xylose-5-t, and d-mannitol-1-t by the reduction of suitable compounds with lithium borohydride-t in anhydrous tetrahydrofuran, followed by hydrolysis of the products. The starting materials for the reductions are, respectively, 1,2-O-isopropylidene-d-glucurono-6,3-lactone, 5-aldo-1,2-O-isopropylidene-d-xylo-pentofuranose, and 2,3:5,6-di-O-isopropylidene-d-mannofuranose. The apparatus and procedure for carrying out the reductions in a closed system are described.