Reduction by sodium amalgam

The superiority of catalytic hydrogenation of the readily available D-glucose as a laboratory method and the commercial availability of sorbitol has rendered the earlier reductions by sodium amalgam of... 

Reduction by sodium amalgam or by zinc and an acid produces sulphurous acid s... 

The reduction of inososes is a method much used for the preparation of new cyclitols. Catalytic hydrogenation in neutral, aqueous solution yields predominantly the isomer with the newly formed hydroxyl group in the axial position,210 whereas the product from a reduction by sodium amalgam usually contains considerable quantities of both the possible epimers.211 Recently, sodium borohydride has been used for reducing inososes62,68 211 in some cases, but not in others, it provides more of the equatorial isomer than does sodium amalgam. 

Dilute HBr hydrolysis of the less soluble bromodeoxyisostrychnine (XXXV R = Br) yields isostrychnine-I (56, 58), whereas hydrolysis of the more soluble salt gives the isomeric isostrychnine-II (XXXVI R = OH), the position of the double bond being fixed by its ease of reduction by sodium amalgam. Isostrychnine-II has not been directly obtained from either strychnine or isostrychnine-I. 

A second ketoheptose was found soon thereafter it occurs in the free state in the herbaceous perennial Sedum spectabile Bor. and it was named sedoheptose, which later became sedoheptulose. Its reduction by sodium amalgam yielded two crystalline heptitols, the identification of which was finally established by Ettel, after one of them had been found to... 

Chemical reduction by sodium amalgam (which does not seem the best choice to obtain [FeCo2(p-COXCO)7(PPh2)2] , because of its much too negative reduction potential) afforded a species not yet characterized, but able to restore the starting precursor upon protonation with H3P04. Nevertheless, it can be foreseen that the monoanion is stable and possesses a geometry quite similar to that of the neutral parent. 

These compounds are monomeric and paramagnetic. The magnetic moment of the allylphosphine vanadium(O) derivative equals 1.98 BM at room temperature. The v(C = C) shifts from 1637 cm in the free ligand to 1513 cm in the complex. Reduction by sodium amalgam leads to the anion [V(CO)5L] in which the ligand is coordinated only through the phosphorus atom. 

Willstatter et al. (3) rejected the theory of nascent hydrogen, as a result of a careful study of the course of reductions by sodium amalgam. They proposed that sodium amalgam reductions start with the addition of metallic sodium to the double bond, the alkali metal being covalently bound to the carbon atom. If this reaction is followed by solvolysis, the attached alkali atoms will be replaced by hydrogen atoms. In this theory the solvent takes no direct part in the fundamental reaction. 

Addition of sulfate (804 ) following the reduction results in precipitation of EUSO4. For large-scale operations, reduction by sodium amalgam (sodium dissolved in mercury) removes europium, samarium, and ytterbium. As a recent development, the separation of Eu can be achieved by photochemical means using lasers. That is, an intense... 

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