Amines sodium metal

The less hindered f/ans-olefins may be obtained by reduction with lithium or sodium metal in liquid ammonia or amine solvents (Birch reduction). This reagent, however, attacks most polar functional groups (except for carboxylic acids R.E.A. Dear, 1963 J. Fried, 1968), and their protection is necessary (see section 2.6). 

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). 

Sodium (metal). Used as a fine wire or as chips, for more completely drying ethers, saturated hydrocarbons and aromatic hydrocarbons which have been partially dried (for example with calcium chloride or magnesium sulfate). Unsuitable for acids, alcohols, alkyl halides, aldehydes, ketones, amines and esters. Reacts violently if water is present and can cause a fire with highly flammable liquids. 

In general, reduction of amides to alcohols is difficult. More commonly the amide is reduced to an amine. An exception uses LiH2NBH3 to give the alcohol. Reduction with sodium metal in propanol also gives the alcohol.Acyl imidazoles are also reduced to the corresponding alcohol with NaBH4 in aqueous HC1. °... 

Angeli pioneered the concept of nucleophilic amine nitration by A-nitrating aniline with ethyl nitrate in the presence of potassium or sodium metal. In this reaction a complex anion... 

Hoff and Feit (8) reacted samples in a 2-cm3 hypodermic syringe before injection onto the gas chromatographic column. Reagents were selected either to remove certain functional groups or to alter them to obtain different peaks. Reagents used included metallic sodium, ozone, hydrogen, sulfuric acid, hydroxyl-amine, sodium hydroxide (20%), sodium borohydride (15%), and potassium permanganate (concentrated). 

Treatment of bis (2-chloroethyl)amine with sodium metal gives l-ethylaziridino among other products.8 3... 

However, sulfonamides are much more difficult to hydrolyze back to the amine than are carboxamides. In peptide synthesis (Section 25-7C) the commonly used sulfonyl protecting groups are 4-methylbenzenesulfonyl or 4-bromo-benzenesulfonyl groups. These groups can be removed as necessary from the sulfonamide by reduction with sodium metal in liquid ammonia ... 

Reaction CLXXIV. Reduction of Oximes to Amines with Metallic Sodium or Sodium Amalgam. 

Stimulated by this work, the electro reduction was tested on the sterically more congested menthoneoxime (7). Substrate 7 - which is derived from optically pure L-menthone - could provide, upon reduction, both epimeric products, (+)-neo-menthylamine (8) and (-)-menthylamine (9), respectively. For both diastereomers there exist unique applications [38, 42-53], The preparation was formerly conducted by treatment with 30 equiv. of sodium metal leading to safety concerns for a scale-up [54]. However, detailed investigations with BDD cathodes indicated that 7 is not a useful substrate. Almost no conversion is observed and only traces of both epimeric amines could be detected. However, the cathodic treatment of 7 using lead results in almost quantitative reduction and a splendid current efficiency (6 F/mol, 66%) [55] (Scheme 4). 

Ozonolysis of vinylpyrazine in methanol at — 30° furnishes pyrazine aldehyde in 73% yield.196 Vinylpyrazine undergoes a variety of addition reactions and pyrazylethyl derivatives of amines, ketones, ethyl phenyl acetate, phenylacetonitrile, and acetamide have been obtained.197-199 2-(2-Pyrazylethyl)cyclohexanone (42) has been prepared both by the condensation of vinylpyrazine with cyclohexanone in the presence of sodium metal and by interaction of vinylpyrazine with the pyrrolidine enamine of cyclohexanone followed by hydrolysis.200... 

Later a breakthrough came when a series of weak base catalysts were discovered that are more active than sodium carbonate or tertiary amines. Alkali metals salts of phosphoric, polyphosphoric, phosphorous, and hypophosphorous adds were proven effective [376,385-389]. 

Chemicals in sealed ampules. After the ampules had been cooled to 0° in an ice bath, they were opened and the contents were added to flasks cooled in ice baths. Small portions (0.5-1.0g.) of sodium metal were added to each of the cold amines, and then the cooling baths were removed and the amines allowed to distill from the sodium into the reaction flask. 

Historically, the first method was the dissolution of alkali metals in amine solvents nevertheless, this is useful only in media in which the lifetime of the solvated electron is long enough (at least a few hours in the pure solvent). For example, in liquid ammonia, the solvated electron may be formed from sodium metal ... 

The most recent source of these iminium ion precursors is the amide derived from 3-chloropropionyl chloride. Using the procedure reported by Ruhlmann for the preparation of 1-methoxy-l-trimethylsilyloxycyclopropane, Wasserman and Dion " converted the piperidide (58) to the 1-piperidino-l-trimethylsilyloxycyclopropane (59) by treatment with sodium metal in dry ether at 0°C. This reaction, which takes place smoothly and in high yield, serves as a short, inexpensive way to form the stable cyclopropanone equivalent. Further reaction of the silyl derivative (59) with tetrabutylam-monium fluoride in THF yields the corresponding carbinol amine (60). 

Very recently, Garst and coworkers 100) have provided a means to suppress the cyclization of (l-methyl-5-hexenyl)sodium with t-butyl amine101 . t-Butyl amine is a sufficiently reactive proton donor to compete successfully with the anion cyclization 138 - cis/trans-139 and the intramolecular 1,4-proton transfer 138 -> 142, leaving 1-heptene 140 as well as cis- and tra -l, 2-dimethylcyclopentane cis,trans-141 formation through radical cyclization only. For sodium metal reactions excess t-butyl amine-nearly eliminates cis,trans-141 suggesting that radical cyclization is negligible. For the Na + N" reaction, 2-heptenes 143 are eliminated by added t-butyl amine, but the yields of cis,trans-141 are merely diminished. As expected, the cis/trans... 

The metal mercaptide can be prepared by the reaction of alkylmercaptan with sodium metal in an organic solvent (e. g. xylene). Carbamoyl chloride is prepared by the reaction of the amine with phosgene in the presence of an acid binder (e.g. /-amine) according to the following scheme ... 

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