Sodium aluminum hydride preparation

Sodium Aluminum Hydride. Sodium aluminum hydride can be prepared from NaH,... 

Sodium aluminate, 2 345t, 358-359 analysis, 2 275-276 economic aspects, 2 275 health and safety factors, 2 276 manufacture, 2 274-275 neutralization, 2 424 physical and chemical properties of, 2 273-274 uses of, 2 276-277 in water treatment, 26 111 Sodium aluminosilicate gels, synthetic zeolites prepared from, 16 831t Sodium aluminosilicates, 12 578 Sodium aluminum hydride, 13 621, 623-624... 

E.C. Ashby, R.D. Schwartz, B.D. James, Concerning the preparation of magnesium aluminum hydride. A study of the reactions of lithium and sodium aluminum hydrides with magnesium halides in ether solvents , Inorg. Chem. 9 (1970) 325-332. 

Complex aluminum and boron hydrides can contain other cations. The following compounds are prepared by metathetical reactions of lithium aluminum hydride or sodium borohydride with the appropriate salts of other metals sodium aluminum hydride [55], magnesium aluminum hydride [59], lithium borohydride [90], potassium borohydride [9i], calcium borohydride [92] and tetrabutylammonium borohydride [95]. 

Reduction of aromatic carboxylic acids to alcohols can be achieved by hydrides and complex hydrides, e.g. lithium aluminum hydride 968], sodium aluminum hydride [55] and sodium bis 2-methoxyethoxy)aluminum hydride [544, 969, 970], and with borane (diborane) [976] prepared from sodium borohydride and boron trifluoride etherate [971, 977] or aluminum chloride [755, 975] in diglyme. Sodium borohydride alone does not reduce free carboxylic acids. Anthranilic acid was reduced to the corresponding alcohol by electroreduction in sulfuric acid at 20-30° in 69-78% yield [979],... 

Sodium aluminum hydride can he prepared from NaH. but direct synthesis from the elements is more economical. 

Sodium aluminum hydride can be synthesized by many different routes. The first preparation was performed by the reaction of NaH and AlBr3 in the presence of dimethyl ether as a solvent [92]. The direct synthesis from NaH and A1 under elevated hydrogen pressures and in various solvents is possible [59, 60]. However, sodium aluminum hydride can also be synthesized by melting the elements in the absence of any solvents (Eq. (5.22)) [93[. 

The reagent is best prepared by the reaction of magnesium iodide and sodium aluminum hydride in THF it is insoluble in this solvent (and also in ether) and separates as the solvate. MglAlH lj THF, in 58% yield. ... 

Sodium tetraalkynyl aluminate salts can be prepared from sodium aluminum hydride 172 and four equivalents of a terminal alkyne. The sodium tetraalkynyl aluminate salts are air stable and easily handled. The fairly reactive alkynyl substituent can be transferred in a cross-coupling mode to aryl bromides such as 5-bromopyridine. All four alkynes are transferrable from one aluminate salt [82]. 

Aldehydes. The reduction of carboxylic acid derivatives such as esters and nitriles is stopped at the aldehyde stage with the modified sodium aluminum hydride. The reagent is prepared from NaAlH2Et2 and piperidine in THF-toluene at 0°C. Interestingly, acid chlorides can be converted to aldehydes by treatment with piperidine and then with NaAlH2Et2- ... 

Alkyl azides prepared by nucleophilic substitution of alkyl halides by sodium azide as shown m the first entry of Table 22 3 are reduced to alkylammes by a variety of reagents including lithium aluminum hydride... 

AletalHydrides. Metal hydrides can sometimes be used to prepare amines by reduction of various functional groups, but they are seldom the preferred method. Most metal hydrides do not reduce nitro compounds at all (64), although aUphatic nitro compounds can be reduced to amines with lithium aluminum hydride. When aromatic amines are reduced with this reagent, a2o compounds are produced. Nitriles, on the other hand, can be reduced to amines with lithium aluminum hydride or sodium borohydride under certain conditions. Other functional groups which can be reduced to amines using metal hydrides include amides, oximes, isocyanates, isothiocyanates, and a2ides (64). 

Hydroxymethylferrocene has been made by condensing ferrocene with N-methylformanilide to give ferrocenecarboxalde-hyde, and reducing the latter with lithium aluminum hydride, sodium borohydride, or formaldehyde and alkali. The present procedure is based on the method of Lindsay and Hauser. A similar procedure has been used to convert gramine methiodide to 3-hydroxymethylindole, and the method could probably be used to prepare other hydroxymethyl aromatic compounds. 

Methylindole has also been prepared by lithium aluminum hydride reduction of 1-methylindoxyl. Compounds giving rise to NH absorption in the infrared (indole, skatole) can be completely removed by refluxing the crude 1-methylindole over sodium for 2 days and then distilling the unreacted 1-methylindole from the sodio derivatives and tarry decomposition products. 

A solution of hydrazoic acid (prepared from about 30 g sodium azide) in ca. 200 ml chloroform is prepared in a well-ventilated hood. Cholesterol (15 g) is dissolved in the hydrazoic acid solution and 3.5 ml of triethylamine is added. The reaction mixture is then stirred at room temperature while 7 g of A-chlorosuccinimide is added. The reaction mixture is allowed to stand overnight and then the chloroform solution is washed successively with dilute sodium bisulfite, dilute soldium bicarbonate solutions and finally with water. The chloroform extract is then dried (Na2S04) and the solvent removed in vacuo. The residue is crystallized from ethanol to yield ca. 8.5 g of (101) in colorless needles mp 138-139°. The chloro azide is reduced to the aziridine by lithium aluminum hydride according to the foregoing procedure. 

Methyl-4-hydroxyquinazoline reacts with organic halides, in the presence of sodium methoxide, to give 3-substituted 2-methyl-4(3i/)-quinazolinones. The 0-acetyl derivative of 4-hydroxyquinazoline has been prepared under anhydrous conditions and gives the hydroxy compound with water or with lithium aluminum hydride. The N-3 acetyl derivative, however, is more stable and gives 3-methyl-4(31/)-quinazolinone with lithium aluminum hydride. ... 

Homoesermetol (1,4a,9-trimethyl-6-methoxy-1,2,3,4,4a, 9a-hexa-hydro-a-carboline (89 R = CH3, R = OCH3) may be prepared in a manner analogous to that used for the preparation of eseroline. Thus, when the 3-y-oxindolylpropylamine 88 (R = CH3, R = OCH3) is reduced with sodium in butanol, homoesermetol is obtained. Reductive cycbzation of 88 (R = R = H) with lithium aluminum hydride has recently been reported. 

Preparation of cholesta-5,7-diene-ia,3/3-diol a solution of 500 mg of the 1,4-cyclized adduct of cholesta-5,7-dien-3/3-ol-ia,2a-epoxideand 4-phenyl-1,2,4-triazoline-3,5-dione in 40 ml of tetrahydrofuran is added dropwise under agitation to a solution of 600 mg of lithium aluminum hydride in 30 ml of THF. Then, the reaction mixture liquid Is gently refluxed and boiled for 1 hour and cooled, and a saturated aqueous solution of sodium sulfate is added to the reaction mixture to decompose excessive lithium aluminum hydride. The organic solvent layer is separated and dried, and the solvent Is distilled. The residue Is purified by chromatography using a column packed with silica gel. Fractions eluted with ether-hexane (7 3 v/v) are collected, and recrystallization from the methanol gives 400 mg of cholesta-5,7-diene-la, 3/3-diol. 

Cyclohexyloxyethanol has also been prepared by reduction of cyclohexyloxyacetic acid with lithium aluminum hydride 8 and by decomposition of cyclohexanone methanesulfonylhydrazone with sodium in ethylene glycol.9... 

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