Acet-aldoxime

It uill be easily understood from these formula why the /3-compound should yield bcn/onitrile vith acetic anhydride whilst thea-compoiind does not. Thepio imity of hydrogen and hydioxyl m the former case facilitates the formation and elimination of water. In this way the configuration of most of the aldoximes may be ascertained. 

Aldoximes can be dehydrated to nitriles by many dehydrating agents, of which acetic anhydride is the most common. Among reagents that are effective under mild... 

Aldoximes can be oxidatively dehydrogenated to nitrile oxides using a variety of oxidants such as lead tetraacetate [16a], alkali hypohalites [lla],NBS in DMF followed by base treatment [16b], chloramine-T [11b], 1-chlorobenzotriazole [16c], mercuric acetate [ 16 d], etc. However, we employed either NaOCl or chloramine-T for most of our INOC reactions. For instance, a piperidine ring fused to an isoxazoline as in 14 was constructed using the INOC methodology (Scheme 3) [17]. Monoalkylation of N-tosylallylamine 10 with the bromoacetal... 

On the other hand, 3-phenylpropionitrile was synthesized from Z-3-phenyl-propionaldoxime (0.75 M) in a quantitative yield (98gP ) by the use of cells of E. coli JM 109/pOxD-9OF, a transformant harboring a gene for a new enzyme, phenylacetaldoxime dehydratase, from Bacillus sp. strain OxB-1. Other arylalkyl- and alkyl-nitriles were also synthesized in high yields from the corresponding aldoximes. Moreover, 3-phenylpropionitrile was successfully synthesized by the recombinant cells in 70 and 100% yields from 0.1 M unpurified P/Z-3-phenylpropionaldoxime, which is spontaneously formed from 3-phenylpropionaldehyde and hydroxylamine in a butyl acetate/water biphasic system and aqueous phase, respectively. 

Then again, many elimination reactions are found to occur much, more readily in that member of a pair of geometrical isomerides in which the atoms or groups to be eliminated are trans to each other than in the isomer in which they are cis (p. 255). As is seen in the relative ease of elimination from and and syn aldoxime acetates to yield the same cyanide ... 

Azido derivatives of furazans have proved to be particularly useful for the synthesis of heterocyclic systems. Thus, by 1,3-dipolar addition of l-azido(4-amino-l,2,5-oxadiazol-3-yl)aldoxime 186 to propargyl alcohol and phenylacetyl-ene, bicyclic 4-amino-l,2,5-oxadiazol-3-yl(4-R-l,2,3-triazol-l-yl)ketoximes 187 were obtained (Equation 34) which in reaction with acetic anhydride afforded the corresponding 0-acyl derivatives <2003RJ0574>. 

Peroxyacetic acid generated in situ from sodium perborate and glacial acetic acid has been used for oxime to nitro group conversion. Peroxyimidic acid generated from acetonitrile and hydrogen peroxide has found similar use. An Mo(IV) peroxy complex has been reported for the oxidation of both ketoximes and aldoximes. 

Sera and coworkers, during their investigation on electroreduction of nitroalkenes, found that plates of powder or metalhc lead can reduce nitroalkene 20 to give oxime 21 in acetic acid-DMF solution without electricity (Scheme 18). The reduction of 1-nitro-1-alkenes afforded the corresponding aldoximes or ketoximes in excellent yield. 

The formation of nitriles from aldoximes was at that time a well-known reaction, at least in its general lines. Gabriel and Meyer found that o-nitrobenzonitrile was obtained by heating o-nitrobenzaldoxime, prepared in an indirect way, with sodium acetate and acetic anhydride Lach prepared benzonitrile in a similar way, and Dollfuss transformed aldoximes of the aliphatic series into nitriles by simple treatment with acetic anhydride. The complicated character of this reaction was demonstrated by the classical work of Beckmann and Hantzsch, who... 

A cyclic hexaacetyl oxime (XII) was also isolated by mild acetylation of D-galactose oxime and by treatment with sodium acetate and acetic anhydride. A cyclic aldoxime acetate (XIII) was also obtained by Voto6ek from D-fucose oxime, and by Restelli de Labriola and Deulofeu ... 

Cycloaddition reactions of nitrile oxides continue to be the source of new isoxazoles and dihydroisoxazoles. The oxidation of a-hydroxyimino acids 1 by ammonium hexanitratocerium(IV) has provided a new method of generation of benzonitrile oxide and other nitrile oxides on the other hand the oxime 2 is simply dehydrogenated by this oxidant to produce benzoylnitrile oxide <99BSJ2277>. Manganese dioxide has also been used to oxidise aldoximes to nitrile oxides the reaction is most efficient with methyl (hydroxyimino)acetate <99TL5605>. ... 

Under the same conditions, aldoximes (E- and Z-isomers), along with the formation of diadduct 144, are sometimes dehydrated to nitriles, ethyl acetate being the second reaction product. This is explained (60RTC888) by decomposition of the intermediate O-vinyloxime 145 (Scheme 71) which, however, has never been isolated. 

Some of these procedures are exemplified in Expt 5.160. Dehydration of aldoximes proceeds under milder conditions, acetic anhydride being frequently used. The method is particularly applicable to the synthesis of aromatic nitriles (see Expt 6.170). 

Lead tetraacetate oxidizes oximes to various products. For exanqrle, the oxime of cyclohexanone gives a-acetoxynitrosocyclohexane in 35% yield.Aldoximes react with lead tetraacetate to give nitrile oxides which then yield acetyl hydroxamates 1 reaction with acetic acid. ... 

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