Reductive deamination

Reactions of this type are called reductive deaminations... 

Reductive deamination of primary arylamines The ammo substituent of an arylamine can be replaced by hydrogen by treatment of its de rived diazonium salt with ethanol or with hypophosphorous acid... 

Other Applications. Hydroxylamine-O-sulfonic acid [2950-43-8] h.2is many applications in the area of organic synthesis. The use of this material for organic transformations has been thoroughly reviewed (125,126). The preparation of the acid involves the reaction of hydroxjlamine [5470-11-1] with oleum in the presence of ammonium sulfate [7783-20-2] (127). The acid has found appHcation in the preparation of hydra2ines from amines, aUphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. It is also an important reagent in reductive deamination and specialty nitrile production. 

Sodium borohydride has also been used to reduce aiyl diazonium salts in reductive deamination reactions. 

Aminoisothiazoles have all been prepared by nitration and subsequent reduction, usually in good yield, although the reduction of 4-nitroisothiazole to 4-aminoisothiazole has only been achieved in 35% yield. 4-Aminoisothiazoles behave as normal aromatic amines and the diazonium salts undergo the Sandmeyer reaction and reductive deamination. ... 

Under more forcing conditions (Raney nickel, MeOH, H2 pressure, 150°C, 6h). 3H-azepin-2-amine undergoes reductive deamination to hexahydroazepine (86 %).240... 

Amino-5-hydrazinopyrazole dihydrochloride 300 is a good source for the synthesis of this type of heterocyclic compound [78JCS(P1)885] and it was prepared by reaction of malononitrile with two equivalents of hydrazine. Reaction of 300 with ethyl pyruvate afforded 301. Unstable hydra-zone 302 formed when 300 was boiled with diacetyl rapidly cyclized to 303. Reaction of 300 with benzil gave 304 directly, which gave an acetyl derivative and resisted reductive deamination. On the other hand, a polymer was isolated from the reaction of 300 with glyoxal (Scheme 65). 

In analogy with phenol, aniline is carboxylated to 4-aminobenzoate followed by reductive deamination to benzoate (Schnell and Schink 1991), which is degraded by pathways that have already been elaborated. 

Schnell S, B Schink (1991) Anaerobic aniline degradation via reductive deamination of 4-aminobenzoyl-CoA in Desulfobacterium anilini. Arch Microbiol 155 183-190. 

In addition to these studies, the Harmata group also successfully achieved the total synthesis (+)-curcumene 208 and curcuphenol 209 utilizing the 2,1-benzothiazine chemistry <03TL7261>. The synthesis of (+)-curcuphenol was accomplished by reduction of benzothiazine 94, followed by protection, desulfurization, reductive deamination and deprotection to give diol 223 in good yield. The latter was then converted into (+)-curcuphenol 209 (Scheme 63). The total synthesis of (+)-curcumene involved a similar approach to that of (+)-cucurphenol. 

Eubacterium acidaminophilum not only reductively deaminates glycine to ammonia and acetate but also expresses enzymes capable of reductively deaminating sarcosine and betaine when cells are cultured in the presence of formate (Hormann and Andreesen 1989). One would expect that the enzymes catalyzing the latter two reactions might be similar to GR. In fact, the substrate-specific protein B for sarcosine reductase was purified and found to be similar to GR protein B from C. sticklandii (Meyer et al. 1995). Apparently, this organism has evolved means to use different amino acids as electron acceptors and preferentially expresses each in response to conditions in the environment. 

Other than water, protein is the major constituent of meat averaging nearly 21% in heef or chicken meat, with fat varying fiom 4.6 to 11.0% in beef and fiom 2.7 to 12.6% in chickoi. The principal radiolytic reactions of aqueous solutions of aliphatic amino acids are reductive deamination and decarboxylation. Alanine yields NH3, pyruvic add, acetaldehyde, propionic acid, CO2, H2, and ethylamine (6). Sulfur-containing amino adds are espedally sensitive to ionizing radiation. Cysteine can be oxidized to cystine by the hydroxyl radical or it can react with the hydrated electron and produce... 

The published research on the photochemical decomposition of di-azonium salts suggests that the two processes, a heterocyclic and a homolytic process, analogous to those of the thermal decomposition may occur. Various workers 36 187 have reported that phenols are formed when diazonium salts are photolyzed in water and aryl ethers result when an alcohol replaces water as the solvent. Homer and Stohr122 report that a process analogous to reductive deamination occurs in preference to ether formation results in alcohols. The importance of free radical intermediates in the photodecomposition, based on magnetic susceptibility measurements, has been stressed.25 Lee and his co-workers171 have recently suggested that in ethanol the photodecomposition of a diazonium salt occurs via a radical intermediate while in water an ionic process predominates. Thus, photodecomposition of a nitrobenzene diazonium chloride in water yielded both a nitrophenol and a chloronitrobenzene in ethanol, on the other hand, the major product of photolysis was the reduction product, nitrobenzene. 

Reductive deamination 10, 37, 39). This is accompanied by the formation of ammonia and a carboxylic acid. The mechanism proposed by Weeks and Garrison 39) for this reaction involves an initial removal of the amino group by H- ... 

Reactions at the a-carbon atom are affected by the presence of 02. First, by rapidly removing the reducing species, it blocks reductive deamination. This is thought to explain the protective effect of 02 on alanine destruction 26). Secondly, 02 also probably alters the mechanism of oxidative deamination though the products (NH3 and the carbonyl group) are the same 39). 

Reductive deamination of 4-isopropyl-2-nitroaniline by diazotization in the presence of ethanol or hypophosphorous acid yields m-nitrocumene and completes the synthesis. 

Hypophosphorous acid has also been used successfully in the reductive deamination step. 

The desired product will be obtained if the nitro group can be removed. This is achieved by its conversion to the corresponding amine, followed by reductive deamination. 

Deamination ofRNHI.t> A new method for reductive deamination of primary amines (1) involves conversion to an aromatic imidoyl chloride (2), which is converted to the hydrocarbon by Bu,SnH and AIBN (10, 412-413). Yields are satisfactory in the deamination of benzylamine, but are only moderate in the reaction of simple alkylamines. 

Diazotization of a mixture of diamino derivatives (R,S)-22 afforded the triazolo[l,5-c]pyrimidine 23. When the reaction time and the proportion of sodium nitrite were increased, a second compound 24, resulting from a reductive deamination of the amino group [89JCS(P1)2401] was obtained (Scheme 5). 

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