N-Acylhydroxylamines

The reduction of 0-acyl oximes to 0-acylhydroxylamines also is accomplished under mild conditions with pyridine-BHs/HCl, NaBHsCN/HCl, and NaBHsCN/AcOH in a similar fashion as with other oxime derivatives. In addition, BH3 (1 equiv.) and the combination of EtsSiH/TFA also effects efficient reduction. With the former reagent, rearrangement to N-acylhydroxylamines has been observed (equation 3). Representative examples of 0-acyl oxime reductions are presented in Table 12. The related derivatives nitrones are also reduced by LAH, or NaBHsCN/H to hydroxylamines (equation 4).202... 

N-Acylhydroxylamines s. Hydroxamic acids O-Acylhydroxylamines s. Acoxylamines Acylimines... 

The Af-aryl-Af-acylhydroxylamines 289 and 290 rearrange to aminophenol derivatives in the presence of sulfonyl chlorides (equation 138) as well as of iodonium salts in a reaction similar to the benzidine rearrangement (equation 139). The A-aryl-N,0-diacylhydroxylamine 291 undergoes isomerization on heating to produce dibenzoylated aminophenol 292 (equation 140) . The Wallach rearrangement consists of isomerization of aromatic azoxy compounds 293 to form the hydroxyazobenzenes 294 on heating in... 

N -I henylmorpholine (Amination of an Arylzinc Derivative with an O-Acylhydroxylamine). This procedure is found in Organic Syntheses.111... 

Alkylations. There are reports on the alkylation of Al-acylhydroxylamines, 1,2,4-tricizole, and glycine methyl ester using DBU as base. In the last case, an a,N,Al-triallyl derivative results because of a [2.3]Stevens rearrangement. 

Boche, G., F. Bosold and S. Schroder. 1988. N-Aryl-O-acylhydroxylamines preparation by O-acylation or N->0 transacylation and reaction with amines model reactions for key steps connected with the carcinogenicity of aromatic amines. Angew. Chem. Int. Ed. Engl. 27 973-974. 

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