Sodium in alcohol

Piperitone is of considerable technical im portance. It is a colourless oil of a pleasant peppermint-like smell. (-)-Piperilone has b.p. 109-5-110-5 C/I5mm. Piperitone yields thymol on oxidation with FeCl. On reduction with hydrogen in presence of a nickel catalyst it yields menthone. On reduction with sodium in alcoholic solution all forms of piperitone yield racemic menthols and womenthols together with some racemic a-phel)andrene. 

Reduction with sodium in alcohol was unsuccessful (54). The introduction of lithium aluminium hydride has provided an elegant method for the reduction of thiazole esters to hydroxythiazoles for example, ethyl 2-methyl-4-thiazolecarboxylate (11 with lithium aluminium hydride in diethyl ether gives 2-methyl-4-(hydroxymethyl)thiazole (12) in 66 to 69% yield (Scheme 7) (53),... 

Isothiazoles are reductively desulfurized by Raney nickel, e.g. as in Scheme 31 (72AHC(l4)l). 1,2,5-Thiadiazoles are subject to reductive cleavage by zinc in acid, sodium in alcohol, or Raney nickel, e.g. Scheme 32 (68AHC(9)107). 

Reduction of esters to alcohols by means of sodium in alcohol... 

Syntheses of members of the lobeline group have been effected by Wieland and Drishaus and by Seheuing and Winterhalder. JiorLobelane was prepared by the former authors by condensing 2 6-dimethylpyridine with benzaldehyde to 2 6-distyrylpyridine (IX), which was then reduced by sodium in alcohol, giving a mixture of meso-and trans- forms of 2 6-di-(3-phenylethylpiperidine (worlobelane). From this by crystallisation of the mixed hydrochlorides, meso-norlobelane was separated, which on A-methylation yielded lobelane (X) as the methiodide. 

Constitution. Pelletierine behaves as a secondary amine and the oxygen atom of the alkaloid is present in the form of an aldehyde group, since the base yields an oxime, convertible by the action of phosphorus pentachloride into a nitrile, b.p. 104-6°/13 mm., which is hydrolysed by caustic potash in alcohol to an acid, the ethyl ester of which is Loffler and Kaim s ethyl -2-piperidylpropionate. Pelletierine is not directly oxidisable to this acid. It also yields a liquid hydrazone, b.p. 130°/20 ram., which with sodium in alcohol at 136-70° reduces to dZ-eoniine. These reactions are explained by the following formulas, in which pelletierine is represented as -2-piperidylpropionaldehyde. 

Willstatter and Bode converted tropinone into (/(-ecgonine by treating sodium tropinone with carbon dioxide and sodium, when it yielded sodium tropinonecarboxylate. This on reduction with sodium in alcohol gave some dZ-i/i-ecgonine (p. 97), which on esterification with methyl alcohol and benzoylation yielded a dhcocainc. A simpler synthesis of ( -eegonine was achieved by Willstatter and Bommer, and reference is made on p, 80 to this and other processes, some of which have been protected by patents. These improvements having enabled the prepara-... 

Hydrocotarnine, C12HJ5O3N. HjO. This basic hydrolytic product of narcotine occurs in opium. It crystallises from light petroleum in colourless plates, m.p. 55-5-56-5°, and yields well-crystallised salts of which the hydrobromide, B. HBr, m.p. 236-7°, is sparingly soluble in water. On oxidation, hydrocotarnine is converted into cotarnine, and on reduction by sodium in alcohol it yields hydrohydrastinine (p. 164) by loss of a mcthoxyl group. 

CjHj) picrate, m.p. 235° methiodide, m.p. 257°. To be distinguished from phenolic dihydrothebaine, m.p. 154° prepared by reduction of thebaine with sodium in alcohol. 

Reoux JP, Saxon AJ, Malte CA, et al Divalproex sodium in alcohol withdrawal a randomized douhle-hlind placeho-controlled clinical trial. Alcohol Clin Exp Res 25 1324-1329,2001... 

The reduction of ketones to alcohols by sodium in alcohol probably involves a very similar mechanism, but there appear to be some differences between... 

Aldehydes and ketones can be reduced to alcohols by hydrogenation, or sodium in alcohol, and by the use of LiAlH4. 

The reduction with nasdcent hydrogen (sodium in alcohol or zinc in acetic acid) leads to the more stable, often the trans isomers. 

Double bonds in alkenyl pyridines may be hydrogenated under mild conditions (Raney nickel at room temperature) to give alkyl pyridines [450]. If the double bond is conjugated with the pyridine ring sodium in alcohol will reduce both the double bond and the pyridine ring in good yields [450]. 

Geminal dihalides undergo partial or total reduction. The latter can be achieved by catalytic hydrogenation over platinum oxide [512], palladium [512] or Raney nickel [63, 512], Both partial and total reduction can be accomplished with lithium aluminum hydride [513], with sodium bis(2-meth-oxyethoxy)aluminum hydride [514], with tributylstannane [503, 514], electro-lytically [515], with sodium in alcohol [516] and with chromous sulfate [193, 197]. For partial reduction only, sodium arsenite [220] or sodium sulfite [254] are used. 

Partial reduction of the aromatic ring is especially easy in anthracene-9-carboxylic acid which was reduced to 9,10-dihydroanthracene-9-carboxylic acid with 2.5% sodium amalgam in aqueous sodium carbonate at 10° in 80% yield [987]. Aromatic carboxylic acids with hydroxyl groups in the ortho positions suffer ring cleavage during reductions with sodium in alcohols and are converted to dicarboxylic acids after fission of the intermediate j8-keto acids. 

Complete reduction of oc,/ -unsaturated esters to saturated alcohols was also accomplished by sodium in alcohol [1078]. 

Reduction with sodium in alcohols, on the other hand, reduces only the ester group and not the free carboxyl. 

Sodium in alcohol opens one thiophene ring of thienothiophene (2) to give 2-ethyl-3-mercaptothiophene (227), which was characterized as its mercury derivative (228) [Eq. (74)]. 

Similarly 2,3 -bipyridine is reduced to 2,3 -bipiperidine by sodium in alcohol or by catalytic hydrogenation. Two forms of 2,3 -bi-piperidine have been reported to be obtained in this way. Partial hydrogenation of 2,3 -bipyridine, for example, by tin and hydrochloric acid affords T,2, 3, 4, 5, 6 -hexahydro-2,3 -bipyridine, an isomer of anabasine (12 ... 

Semicarbazones are reduced by sodium amalgam in alcohol [69,70], sodium in alcohol [71 ], sodium hydrosulfite [72], or catalytic hydrogenation using either platinum [73, 74], platinum oxide [75, 76], or Raney nickel [71]. The method involving sodium hydrosulfite is simple and is preferable to the other methods (Eq. 27). 

The catalytic hydrogenation of 7,7-dihalonorcaranes proceeds with opening of the three-membered ring and leads ro methylcyclohexane, whereas the reduction with sodium in alcohols affords norcarane [2], Hydrogenolysis of l,l-difluoro-2-methyl-3-phenylcyclopropane in the presence of a Ni—Re or Pd catalyst at atmospheric pressure provides a mixture of 1 -phenyl-butane, l-phenyl-2-fluorobutane, and l-phenyl-2,2-difluorobutane, respectively [25],... 

The 3-amino isomers are more resistant towards reduction 3-amino-5-phenyl-l,2,4-thiadiazole is not affected by hydrogen sulfide or acidified potassium iodide, but does undergo decomposition under the influence of stannous chloride in acids or sodium in alcohol.126 Zinc in hydrochloric acid cleaves the heterocyclic nucleus completely, benzoic acid and hydrogen sulfide being the main products,126 while, under the same conditions, the 3-toluene-p-sulfonyl derivative yields benzal-dehyde and toluene-p-sulfonylguanidine.125... 

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