Sodium in ethanol

Calciferol, when hydrogenated catalyticaky, took up 4 moles of hydrogen and gave a compound with the empirical formula C2gH 2D. Sodium in ethanol reduction gave a dihydroproduct that reacted with 3 moles of perbenzoic acid, thus demonstrating the derivative to have three double bonds. 

Ketones can be reduced by the Wolff-Kishner method to the corresponding alkyl compounds, or by sodium in ethanol to the corresponding alcohols. An alkali-catalyzed deacylation of 3-acetyl-6-methoxypyridazine 1-oxide occurs quantitatively on treatment with dilute sodium hydroxide. 

Dibenz[/>,e]azepines, e.g. 15, are reduced readily to the 5,6-dihydro derivatives, e.g. 16, with hydrogen and palladium on charcoal, or Raney nickel, at room temperature,28,104 with sodium in ethanol,104 with sodium borohydride in methanol,104 and with lithium aluminum hydride in diethyl ether.115... 

Reductions of 5//-dibenz[/j,/]azepines to their 10,11-dihydro derivatives have been accomplished in high yield with sodium in ethanol,29 133 with copper(II) chromite (2CuO Cr203) and barium carbonate,224 with 5 % palladium on charcoal29 or platinum(IV) oxide30 in ethanol, and with magnesium in methanol.225 4//-Thieno[3,2-/)][1]benzazepine is reduced similarly with hydrogen and palladium on charcoal in ethanol.137... 

Thus, the dianion derived from a-amino acid substitutes the /1-chloride to give the ester of 2-(phenylsulfonyl)ethenyl amino acid and subsequent desulfonylation provides N-(benzoyl)vinylalanine methyl ester (62) (equation 61). The conjugate addition of enolates to methyl styryl sulfone (63) and subsequent intramolecular addition to the carbonyl moiety provide a synthetically valuable method for the construction of bicyclic and tricyclic skeletons52. Desulfonylation of the cyclization product 64 with sodium in ethanol-THF gives the diene 65 in good yield (equation 62). 

Although catalytic hydrogenation is the method most often used, double bonds can be reduced by other reagents, as well. Among these are sodium in ethanol, sodium and rerr-butyl alcohol in HMPA, lithium and aliphatic amines (see also 15-14), " zinc and acids, sodium hypophosphate and Pd-C, (EtO)3SiH—Pd(OAc)2, trifluoroacetic acid and triethylsilane (EtsSiH), and hydroxylamine and ethyl acetate.However, metallic hydrides, such as lithium aluminum hydride and sodium borohydride, do not in general reduce carbon-carbon double bonds, although this can be done in special cases where the double bond is polar, as in 1,1-diarylethenes and in enamines. " °... 

Sodium in Ethanol This is called the Bouveault-Blanc procedure and was more popular for the reduction of carboxylic esters (19-38) than of aldehydes or ketones before the discovery of LiAlH4. 

For the reaction with sodium in ethanol the following mechanism been suggested ... 

The reductive removal of halogen can be accomplished with lithium or sodium. Tetrahydrofuran containing /-butanol is a useful reaction medium. Good results have also been achieved with polyhalogenated compounds by using sodium in ethanol. 

A more recent synthesis proceeds via 2,5-diarylamino-3,6-dicarbethoxy-l, 4-hy-droquinone 65, which is obtained by reducing 2,5-diarylamino-3,6-dicarbethoxy-1,4-benzoquinone 64 with sodium hydrogensulfite or sodium in ethanol ... 

Many reductions with sodium are carried out in boiling alcohols in methanol (b.p. 64°), ethanol (b.p. 78°), butanol (b.p. 117-118°), and isoamyl alcohol (b.p. 132°). More intensive reductions are achieved at higher temperatures. For example reduction of naphthalene with sodium in ethanol gives 1,4-dihydronaphthalene whereas in boiling isoamyl alcohol tetralin is formed. 

Reduction of diphenylacetylene with sodium in methanol or with zinc yielded stilbene, whilst reduction with sodium in ethanol gave 1,2-diphenyl-... 

The pyridine ring is easily reduced in the form of its quaternary salts to give hexahydro derivatives by catalytic hydrogenation [446], and to tetrahydro and hexahydro derivatives by reduction with alane aluminum hydride) [447], sodium aluminum hydride [448], sodium bis 2-methoxyethoxy)aluminum hydride [448], sodium borohydride [447], potassium borohydride [449], sodium in ethanol [444, 450], and formic acid [318]. Reductions with hydrides give predominantly 1,2,5,6-tetrahydro derivatives while electroreduction and reduction with formic acid give more hexahydro derivatives [451,452]. 

As a consequence of the wide choice of hydride reagents the classical methods such as reduction with sodium in ethanol almost fell into oblivion [579, 520]. Nevertheless some old reductions were resuscitated. Sodium di-thionite was found to be an effective reducing agent [262], and the reduction by alcohols [309] was modified to cut down on the temperature [755] or the time required [527], or to furnish chiral alcohols ( in good yields and excellent optical purity ) by using optically active pentyl alcohol and its aluminum salt [522]. Formation of chiral alcohols by reduction of pro-chiral ketones is... 

The parent perhydroquinazoline diastereomers were synthesized by Armarego in the late 1960s. Reduction of 5,6,7,8-tetrahydroquinazoline with sodium in ethanol resulted in the trans-fused perhydroquinazoline 237 exclusively [69JCS(C)1635]. Both cis and trans isomers were prepared in an alternative way reaction of the cis and trans diamines 236 with formalde-... 

The reduction of iV-alkylpiperidones with sodium in ethanol has also been reported [139a, b]. 

Cyclobutyl phenyl sulfides are reduced with sodium in liquid ammonia,150 while cyclobutyl phenyl sulfones are reduced either by sodium amalgam,SI -152 or sodium in ethanol.153 In the latter case, an alkene results if the sulfonyl group has a neighboring acetyl group, i.e. reduction of li , 2/ , 3S )-l-(l-acetoxy-2-methylpropyl)-2,3-dimethyl-1-phenylsulfonylcyclobutane gave lram -l,2-dimethyl-3-(2-methylpropylidene)cyclobutane (16).153... 

Pyridines are more susceptible to reduction than benzenes. Sodium in ethanol or in liquid ammonia evidently reduces pyridine to 1,4-dihydropyridine (or a tautomer) because hydrolysis of the reaction mixture affords glutaric dialdehyde (318 — 317 — 316). Reduction of pyridines with sodium and ethanol can proceed past the dihydro stages to A3-tetrahydropyridines and piperidines (318 — 319 and 320). 

In addition to its susceptibility to oxidation, 2-aminoindole is easily converted into oxindole by aqueous acids and is deaminated by sodium in ethanol (72HC(25-1)227). 

Dihydro-1,2,4,5-tetrazines (41) can be reduced by hydrogen sulfide to tetrahydro-1,2,4,5-tetrazines (44) (72HCA1404), while with zinc in acetic acid, sodium in ethanol or diimide they afford 1,2,4-triazoles (118 Scheme 7) (78HC(33)1075, p. 1154). 

Only the trifluoromethyl group has been subjected to reduction in this class of compound. Although not reduced by zinc in acetic acid or by sodium in ethanol, diethyl 2-methyl-4-(tri-fluoromethyl)-1//-pyrrole-3,5-dicarboxylate (1) is reduced at the trifluoromethyl group with an excess of lithium aluminum hydride to give the corresponding tetramethyl derivative 2 sodium borohydridc in ethanol is quite inefficient.104... 

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