Reduction with sodium amalgam

The reducing action of sodium amalgam is similar to that of sodium and alcohol. Double bonds are resistant when isolated but reactive when conjugated. According to Kuhn and Hoffer,15 polyenes always add the hydrogen at the ends of the conjugated system. 

For the preparation of 3-phenylpropionic acid (hydrocinnamic acid), as described by Henle,26 cinnamic acid (15 g) is dissolved in 5% sodium hydroxide solution (75 ml) with warming, the solution is cooled, and freshly prepared 2.5 % sodium amalgam is added slowly 

Gattermann and H. Wieland, Die Praxis des organischen Chemikers, Walter de Gruyter and Co., Berlin, 1947. 

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Nitrogen cannot be eliminated from the latter by further methylation, but (VIII) on catalytic hydrogenation has its vinyl group converted into ethyl and the product, on methylation followed by reduction with sodium amalgam, yields 6-dimethylamino-3 4 3 4 -tetramethoxy-6 -ethyl-a)3-diphenylethane (X), and this, on repetition of the methylation, and reduc-... 

On reduction with sodium amalgam the acid adds on two atoms of hydrogen the resulting amorphous aeid yields a crystalline dimethyl ester, C2iH2gOgN2, colourless prisms, m.p. 143-7° dec.). On hydrogenation in presenee of platinic oxide as catalyst 2 mols, of hydrogen are absorbed to form the acid, CjgHjgOgNj, colourless prisms, [ajo - -17-7° (HjO). On oxidation with chromic acid the Cjg acid is converted into Wieland s Ci7 acid and Hanssen s Cjg acid. ... 

Toluene from Toluidine.—It is often desirable to obtain tbe hydiocarbon from the base. The process of diazotisntion offers the only convenient method. The diazonium salt may be reduced by alcohol (Reaction 1, p. 162) or, as in the piesent instance, by sodium stannite. Less direct methods are the con-veision of the diazonium compound into (i) the hydrazine (see p. 174), (2) the acid and distillation with lime (p. 200), (3) the halogen derivative and reduction with sodium amalgam, 01, finally (4) the phenol and distillation with zinc dust. 

Benzoin yields hydrobenzoin on reduction with sodium amalgam, and clesoxybenzoin, C H,CO.CHj.C,Hj, when reduced with zinc and hydrochloric acid. 

Vinyl sulfones are reactive as dienophiles. The sulfonyl group can be removed reductively with sodium amalgam (see Section 5.6.2). In this two-step reaction sequence, the vinyl sulfone functions as an ethylene equivalent. The sulfonyl group also permits alkylation of the adduct, via the carbanion. This three-step sequence permits the vinyl sulfone to serve as the synthetic equivalent of a terminal alkene.68... 

The 3,6-anhydro-D-glucose (XIX) of Fischer and Zach13 on reduction with sodium amalgam or with hydrogen in the presence of Raney nickel14 gives 3,6-anhydro-D-sorbitol (XX), a method of synthesis which establishes the ring structure of the substance since that of 3,6-anhydro-D-... 

Reductions with sodium amalgam are fairly mild. Only easily reducible groups and conjugated double bonds are affected. With the availability of sodium borohydride the use of sodium amalgam is dwindling even in the field of saccharides, where sodium amalgam has been widely used for reduction of aldonic acids to aldoses. 

REDUCTION WITH SODIUM AMALGAM Preparation of Sodium Amalgam [68]... 

When y-cyanopropylmalonic ester is treated with nitrous acid, it loses one of its carboxethyl groups and is converted into a-oximido-8-cyanovalerianic acid, which on reduction with sodium amalgam yields a, e-diaminocaproic acid, thus —... 

This compound on reduction with sodium amalgam and hydrolysis with water gives tryptophane —... 

Various processes separate rare earths from other metal salts. These processes also separate rare earths into specific subgroups. The methods are based on fractional precipitation, selective extraction by nonaqueous solvents, or selective ion exchange. Separation of individual rare earths is the most important step in recovery. Separation may be achieved by ion exchange and solvent extraction techniques. Also, ytterbium may be separated from a mixture of heavy rare earths by reduction with sodium amalgam. In this method, a buffered acidic solution of trivalent heavy rare earths is treated with molten sodium mercury alloy. Ybs+ is reduced and dissolved in the molten alloy. The alloy is treated with hydrochloric acid, after which ytterbium is extracted into the solution. The metal is precipitated as oxalate from solution. 

Aminonaphthol has been prepared by the reduction of 1.4-nitronaphthol by tin and hydrochloric acid 1 by the reduction with sodium amalgam of i,4-aminonaphthol-3,8-disul-fonic acid 2 or i,4-aminonaphthol-5-sulfonic acid 3 by the action of phenylhydrazine on 1,4-nitrosonaphthol.4 The more usual preparative method has been to start with a-Naphthol Orange (Orange I) and reduce it with stannous chloride.8... 

OB to C02 —72.7%, unstable in free state prepd from following entry by reduction with sodium amalgam... 

Attempted18 transformation of 12 into DL-erythrose by direct reduction with sodium amalgam, or by hydrogenation in the presence of platinum catalyst, failed the reduction proceeded to the stage of erythritol. 

Mercapto-l,2,4-thiadiazoles are oxidized, by 2N nitric acid at 50-60°, by chromic acid mixture, chlorine, or potassium permanganate to the disulfides, which are reconvertible to the thiols by reduction with sodium amalgam and alcohol.71,72,91 168 Use of excess chlorine in aqueous acetic acid results in replacement of the mercapto group by the halogen.168... 

On the otner hard,if this were the correct formula the compound should readily add bromine and reduce potassium perm ngante the first reaction it gave only in the sunlight,the other not at all1. These facts,its stability towards reduction with sodium amalgam, the value of its magnetic rotation and the fact that it behaved like a disubstltuted malonic acid4 settled the dispute in favor of Perkin. 

A hexose, C6H1206, which we shall call X-ose, on reduction with sodium amalgam gives pure D-sorbitol, and upon treatment with phenylhydrazine gives an osazone different from that of D-glucose. Write a projection formula for X-ose and equations for its reactions. 

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