Amines, reductive deamination

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. 

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... 

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. 

The mechanism of reduction is postulated to involve a 2e reduction of the 1,6 double bond, and immediate 2e reduction of the product, to give 1,2,3,6-tetrahydroadenine. This, in turn, undergoes reductive deamination to form 2,3-dihydropurine, which is further reduced to 1,2,3,6-tetrahydropurine, followed by cleavage of the 2,3 bond with formation of the same diazotizable amine as in purine reduction 153-i6. 162> One reported observation in apparent conflict with this scheme is the detection of purine as an intermediate 1631. On cyclic voltammetry at the H.M.D.F., adenine exhibits a single pH-dependent cathodic peak, with no anodic peak on the return scan 36). 

Primary amines on treatment with HNF2 undergo reductive deamination, resulting in the formation of alkanes (30, 32). Optically active 2-phenyl-2-butylamine reacts with HNF2 to give 2-phenylbutane with 56% net retention of configuration (29). 

Chemically, methods for deoxygenation and reductive deamination have seen additions in the last two decades which depart from those traditional approaches using hydride reduction of activated alcohols and diazene generation from aliphatic amines. New methods for amine activation, new complex hydrides and, in particular, methods using electron transfer and free radical processes have greatly expanded the range of substrate molecules which can be subject to efficient functional group removal. 

The success of the Wolff-Kishner and related C==0 to CH2 transformations (see Chapter 1.14, this volume) attests to the efficiency of the diazene decomposition route applied to the reductive deamination of primary amines, this requires methods which transform RNH2 into RN=NH, which corresponds to an amination-oxidation sequence. Several one- or two-step processes have been described which carry out this transformation. Treatment of amino acids in alkaline solution with excess hydroxylamine-O-sul-fonic acid (HOS) gave moderate yields of deamination product, as exemplified by the dipeptide case shown in equation (23). 

Some preparative importance attaches also to reductive deamination of tertiary Mannich bases, which are accessible by condensation of a CH-acidic compound with formaldehyde and a secondary aliphatic amine. By this route... 

Reductive deamination. The reagent is prepared from benzenesulfinic acid and dinitrogen tetroxide in THF. Aromatic amines undergo deamination in the presence of CuCli. 

Reductive deamination Aromatic amines are converted to deaminated aromatic compounds with NO in THF under argon. The yields range from trace amounts to 92%. 

Reductive deamination can be performed in reasonable yields via phenylimidoyl chlorides prepared from benzoyl derivatives of primary amines. Imidoyl chloride derivatives decompose on heating with TBTH and AIBN in xylene to yield alkanes (equation 80) . Primary amines can also be reductively deaminated in high yields via isocyanide derivatives. Formylation-dehydration transforms an amino group into an isocyanide quite routinely. Reductive removal of isocyanide can be performed with sodium naphthalenide in hydrocarbon solvents " or with TBTH in the presence of AIBN ". The TBTH reduction works equally well for primary, secondary and tertiary isocyanides and yields are good (equation 81) ". ... 

After the synthesis of the first nucleotides, metabolic regulation must be directed toward the control of interconversions to yield the proper varieties and balance of the required nucleotide classes. Ring substitutions are made via processes of oxidation, reduction, amination, and deamination. Feedback loops and recycling mechanisms are marshaled for the control of these interconversions. Reductive conversions of ribonucleotides to their deoxyribose counterparts are also regulated by both negative and positive feedback loops. 

Deamination of aliphatic amines. Benzenesulfonylbenzylamine from benzyl-amine dissolved in aq.-alc. NaOH, solid hydroxylamine-O-sulfonic acid added portion wise, and distilled during ca. 1 hr. toluene. Y >95% based on startg. m. consumed conversion 63%.—A direct method for effecting reductive deamination of aliphatic prim, amines has not been hitherto available. F. e. s. A. Nickon and A. Sinz, Am. Soc. 32, 753 (1960). 

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