Sodium tetrahydridoaluminate

The tetrahydrofuran used in the synthesis is dried immediately prior to use and is purified by atmospheric-pressure distillation over sodium tetrahydridoaluminate(l — ) under a nitrogen atmosphere. The use of lithium tetrahydridoaluminate(l —) is to be avoided because of reports that it explodes on distillation. The following precautions should be observed when distilling tetrahydrofuran over sodium tetrahydridoaluminate(l —). 

Sodium tetrahydridoaluminate(l —) has been found to be superior to lithium tetrahydridoaluminate(l-) as a drying agent over which tetrahydrofuran is distilled. Tetrahydrofuran distills at 65°, a temperature at which lithium tetrahydridoaluminate( 1 -) is already decomposing slowly. As tetrahydrofuran is distilled from a flask containing lithium tetrahydrido-aluminate(l —) the temperature of the pot increases and can reach a temperature of 90°, at which lithium tetrahydridoaluminate(l-) decomposes rapidly and has been known to detonate. On the other hand, sodium tetra-hydridoaluminate(l-) decomposes at 185°, a temperature far above temperatures expected in the distillation flask during distillation. Under no condition should the distillation of tetrahydrofuran over sodium tetra-hydridoaluminate(l —) be allowed to proceed to dryness. Preferably the distillation should be stopped just as the solvent layer reaches the top of the heating mantle. 

Bonnetot B, Chahine G, Claudy P, Diot M, Letoffe J M (1980), Sodium tetrahydridoaluminate NaAlHj and hexahydridoaluminate Na3AlHg molar heat capacity and thermodynamic properties from 10 to 300 K , J. Chem. Thermodyn., 12(3), 249-254. 

Upon pulse radiolysis of traws-stilbene (t-St) solutions in THE, the radical anion of trans-stilbene was demonstrated to be formed by the reaction of electrons with St (reaction with the rate constant ks = (1.16 0.03) x 10 dm /(mol s)) [86]. The transient absorption spectrum observed with Xmax 500 and 720 nm was attributed to the unassociated radical anion St" . This species reacted with the countercation of THE formed upon radiolysis and with radiolytically generated radicals. Addition of sodium tetrahydridoaluminate (NAH) resulted in the radical anion being associated with Na as a contact ion pair. In the presence of the lithium salt, formation of solvent-separated ion pairs has been detected. 

Sodium tetrahydridoaluminate Aldehydes from carboxylic acid esters Hydroxyaldehydes from lactones... 

The tetrahydridoborate ion, as "sodium borohydride" NaBH is soluble in water and is similarly an excellent reducing agent in this solvent. (Lithium tetrahydridoaluminate cannot be used in water, with which it reacts violently to give hydrogen.)... 

Tellurium Tetrahydrofuran Tetranitroaniline Tetranitromethane Thiocyanates Thionyl chloride Thiophene Thymol Halogens, metals Tetrahydridoaluminates, KOH, NaOH Reducing materials Aluminum, cotton, aromatic nitro compounds, hydrocarbons, cotton, toluene Chlorates, nitric acid, peroxides Ammonia, dimethylsulfoxide, linseed oil, quinoline, sodium Nitric acid Acetanilide, antipyrine, camphor, chlorohydrate, menthol, quinine sulfate, ure- thene... 

Lithium tetrahydroaluminate Lithium tetrahydridoaluminate Sodium tetrahydroborate Sodium tetrahydridoborate Lithium trialkoxyhydridoaluminate Sodium bis(2-methoxyethoxy)dihydro-aluminate Diisobutylalane Tributylstannane... 

Reductive defluorination reactions have also been described in ether, difluoroallylic alkoxides undergo stereoselective reduction (Eq. 138) to the E-mono-fluoro derivatives upon treatment with lithium tetrahydridoaluminate [354]. Sodium borohydride [355] and Red-Al [346] have also been used to achieve this transformation. 

The solvents should be free of air and water. Pyridine and 1,5-cyclooctadiene were distilled under nitrogen. Tetrahydrofuran was distilled from lithium tetrahydridoaluminate(l —) and stored over sodium in a nitrogen atmosphere. Pentane was dried over molecular sieve and sparged with nitrogen. 

The tetrahydrofuran is dried and purified by shaking with sodium hydroxide pellets, refluxing 24 hr over sodium metal, and distilling in an inert atmosphere from lithium tetrahydridoaluminate or sodium diphenylketyl immediately before use. Other solvents are dried and purified in the usual way. 2 Alkyl or aryl halides are also freshly distilled. 

Reduction of 2,2-dimethyl-1-phenylphosphorinan-4-one 1--sulphide with lithium tetrahydridoaluminate, sodium tetra-hydridoborate, aluminium isopropoxide, or sodium in ethanol gives a mixture of two stereoisomers (1) and (2) of 2,2--dimethyl-1-phenylphosphorinan-4-ol 1-sulphide (Z.A. Abramova, Yu. G. Bosyakov, and K.B. Erzhanov, Izv. Akad. Nauk Kaz. SSR, Ser. Khim., 1978, 28, 33). 

Octylamine 28 A solution of heptyl cyanide (12.5 g, 0.10 mole) in ether (20 ml) is dropped slowly into one of lithium tetrahydridoaluminate (3.8 g, 0.12 mole) in anhydrous ethanol (200 ml) at 0° (ice-bath). Then, with continued cooling and vigorous stirring, are added successively water (4 ml), 20% sodium hydroxide solution (3 ml), and again water (14 ml). The ethereal solution is decanted from the white inorganic residue, the latter is washed with a little ether, the combined ethereal solutions are evaporated, and the residue is distilled in a vacuum, giving octylamine (11.5-11.9 g, 89-92%), b.p. 53°/6 mm. 

Metal hydrides such as lithium tetrahydridoaluminate have been used for reduction of aliphatic and alicyclic nitro to amino compounds in general, 2 moles of this aluminate are applied per mole of nitro compound. However, aromatic nitro compounds are usually reduced thereby only to the azo stage. Indeed, apart from special cases, the reduction of nitro compounds by lithium tetrahydridoaluminate has only slight practical importance.27 Sodium tetra-hydridoborate had been recommended for reduction of o-nitrophenol in the presence of a palladium-charcoal catalyst.73... 

Tin or tin(n) chloride,171 zinc in an acid medium,172 sodium dithionite,173 and sulfur dioxide174 are also effective for reducing A-oxides. Azoxy compounds are converted into azo or hydrazo compounds by relatively mild reducing agents azoxybenzene is reduced to hydrazobenzene by zinc in alkaline solution10 and to azobenzene (99% yield) by lithium tetrahydridoaluminate.35... 

C2HjCN + OH" + H2O C2H3COO" + NHj conditions heat under reflux with dilute sodium hydroxide Reduction by lithium tetrahydridoaluminate(lll) ... 

Lithium tetrahydridoaluminate sodium hydroxide Reductive imidazolidine ring opening... 

Lithium tetrahydridoaluminate s. under TiCl Sodium trihydridocyanoborate s. under TiCl ... 

In 1956 Herbert C. Brown (b. 1912) discovered that in ethereal solution diborane (B2H5) dissociates into borane (BH3), which can add to an alkene. The organoborane formed can be converted to an alcohol by treatment with hydrogen peroxide, and the overall result of this hydroboration reaction is the anti-Markovnikoff addition to the double bond. Brown was also responsible for the introduction into organic chemistry of the reducing agents sodium borohydride (sodium tetrahydridoborate(lll)) and lithium aluminium hydride (lithium tetrahydridoaluminate(lll)). 

There are two common hydride reducing agents sodium borohydride (7 NaBH4) and lithium aluminum hydride (8 LiAlH4). Borohydride is an ate complex (see Chapter 6, Section 6.5.4, for definition of an ate complex) of BHg (7 is a tetrahydridoborate) and aluminum hydride is an ate complex of AlHg (8 is a tetrahydridoaluminate their respective lUPAC names are sodium tetrahydridoborate and lithium tetrahydridoaluminate. The borate anion is the Lewis acid-Lewis base complex of BHg (borane) and a hydride, whereas the alumi-nate anion is the Lewis acid-Lewis base complex of AlHg (aluminum hydride) and a hydride. Examination of the periodic table reveals that hydrogen is more... 

Lithium tetrahydridoaluminate sodium methoxide Li[AlHJ/NaOMe... 

The reducing agent used is usually an aqueous alkaline solution of sodium tetrahydridoborate, NaBH, or lithium tetrahydridoaluminate, LiAlH, in dry ether. 

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