Oxime esters reduction

Reduction of oximino esters, i.e. oximes of keto esters, is very useful for the preparation of amino esters. Reductions are very selective since the oximes are easily reduced by catalytic hydrogenation over 10% palladium on carbon in ethanol (yield 78-82%) I094, by aluminum amalgam in ether (yields 52-87%) [750, 70P5], or by zinc dust in acetic acid (yield 77-78%). None of these reagents attacks the ester group. The last mentioned reaction gives an N-acetyl derivative [1096. ... 

Reduction of Oximes, Oxime Ethers and Oxime Esters to Hydroxylamines and Derivatives... 

Oxime esters 3.280 can be reduced to acyloxyamines by NaCNBH, in AcOH [GNl, SJl] (Figure 3.106). On the other hand, BH3 THF or NaBH4-l2 converts oxime ethers to amines and to the corresponding alcohols [BCl 1, H3]. NaCNBHj-T1CI4 in aqueous MeOH converts oximes into amines this reduction is compatible with ketones, esters, acetals, and isolated double bonds [LK2]. 

In the presence of chloramine T, the non-reducing end oxime 42 underwent 1,3-polar cycloadditions with terminal alkynes to give 3-glycosyI-5-substituted isoxazoles 43 in moderate yields. Reductive alkylation of pyrroline derivative 44 with methyl 2,3,4-tri-0-benzyl-6-deoxy-6-iodo-a-D-glucopyranoside gave, after ester reduction, osmylation and acetylation-deacetylation, the novel poly-hydroxypyrrolidine 45, containing a methyl glucoside moiety. ... 

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. 

H-Benzimidazole, 2,2-pentamethylene-reduction, 5, 423 Benzimidazole-2-carbaldehyde oximes, 5, 436 Benzimidazolecarbaldehydes oxidation, 5, 437 Benzimidazole-2-carbamates 5-substituted as anthelmintics, 1, 202 Benzimidazole-1-carboxylic acid, 2-amino-methyl ester reactions, 5, 453... 

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