Deamination transform

The following deamination transform, 28 => 29, illustrates how FGA can be used for positional control for a subsequent aromatic FG removal (FGR) transform, 29 => 30. 

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. 

Both enzymatic and whole cell-mediated transformation of sulfonamides has been described, usually with high removal efficiencies and relatively short treatments. Although different metabolites have been elucidated, no clear pathways have been defined however, the desulfonated metabolites have been widely identified (with LAC and fungal cells) along with the products of hydroxylation, formylation, and deamination reactions, and combinations of them. 

The herbicide known as Metamitron (Fig. 8) can be transformed microbio-logically to yield a deaminated product which is non-toxic [169]. 

Amidases can be found in all kinds of organisms, including insects and plants [24], The distinct activities of these enzymes in different organisms can be exploited for the development of selective insecticides and herbicides that exhibit minimal toxicity for mammals. Thus, the low toxicity in mammals of the malathion derivative dimethoate (4.44) can be attributed to a specific metabolic route that transforms this compound into the nontoxic acid (4.45) [25-27]. However, there are cases in which toxicity is not species-selective. Indeed, in the preparation of these organophosphates, some contaminants that are inhibitors of mammalian carboxylesterase/am-idase may be present [28]. Sometimes the compound itself, and not simply one of its impurities, is toxic. For example, an insecticide such as phos-phamidon (4.46) cannot be detoxified by deamination since it is an amidase inhibitor [24],... 

Corey s retrosynthetic concept (Scheme 9) is based on two key transformations a cationic cyclization and an intramolecular Diels-Alder (IMDA) reaction. Thus, cationic cychzation of diene 50 would give a precursor 49 for epf-pseudo-pteroxazole (48), which could be converted into 49 via nitration and oxazole formation. Compound 50 would be obtained by deamination of compound 51 and subsequent Wittig chain elongation. A stereocontroUed IMDA reaction of quinone imide 52 would dehver the decaline core of 51. IMDA precursor 52 should be accessible by amide couphng of diene acid 54 and aminophenol 53 followed by oxidative generation of the quinone imide 52 [28]. 

Dichloronitrobenzene has been prepared by deamination of 3,5-dichloro-4-nitroaniline and of 2,4-dichloro-3-nitroaniline. This procedure is an example of the rather general oxidation of anilines to nitrobenzenes with peroxytrifluoroacetic acid. Use of this reagent is frequently the method of choice for carrying out this transformation, and it is particularly suitable for oxidation of negatively substituted aromatic amines. Conversely, those aromatic amines, such as />-anisidine and j8-naphthylamine, whose aromatic nuclei are unusually sensitive to electrophilic attack give intractable mixtures with this reagent. This is not... 

Aziridines can undergo loss of a nitrogen atom in a number of ways and this process is frequently stereospecific in terms of the alkene formed. For example, the reaction of aziridines, e.g. (268), with nitrosating agents such as nitrosyl chloride or methyl nitrite results in the formation of alkenes wit.h greater than 99% stereoselective deamination (64JOC1316). Such transformations proceed via N- nitrosoaziridine intermediates which are isolable at temperatures below -20 °C, but which decompose to the observed products at higher temperatures. 

Figure 6.43 Mechanism of a mutagenic transformation by deamination of adenine to hypoxanthine. Hypoxanthine (Fig. 4.29) pairs like guanine, and this results in a transition A T—>G C. Source Adapted from Ref. 12.

Elimination to give alkenes is a major reaction-pathway in the deamination of simple amines. The relative unimportance of elimination for amino groups equatorially attached to six-membered rings has been attributed to the fact that, in the supposed transformation from diazonium ion to carbonium ion, the developing carbon p-or-... 

For the DEAand TEA Y zeolites treated under vacuum, the OH stretching bands do not appear (see, for instance, Figure 4A). This would result from the negligible transformation into NH4+. This is also in agreement with the observation by Jacobs el al. (7) that the deamination of DEA and TEA Y zeolites does not lead to the stoichiometric formation of OH groups. 

The enzymic oxidative deamination of simple phenethylamines is exemplified by the reported bio transformations of mescaline (146) (114, 115) and ephedrine (148) (116). Mescaline is metabolized to 3,4,5-trimethoxy-phenylacetic acid by tissue homogenates of mouse brain, liver, kidney, and heart (114,115). 3,4,5-Trimethoxybenzoic acid is also formed as a minor metabolite. The formation of jV-acetylmescaline (147), a significant metabolite in vivo, was not observed in the in vitro studies. Both D-(—)-and L-(+)-ephedrine have been incubated with enzyme preparations from rabbit liver norephedrine (149), benzoic acid, and 1-phenyl-1,2-propanediol were characterized as metabolites (116). The D-(—)-isomer was the better substrate, being more rapidly converted. Similar results were previously reported with rabbit liver slices as the source of enzyme (153,154). The enzymic degradation of the side chain of /i-phenethylamines has been extensively investigated with nonalkaloid substrates such as amphetamine (151) and jV-methylamphetamine (150) (10,155-157), and the reader is referred to these studies for a more comprehensive coverage of this aspect of the subject. 

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