Oxygen oxime hydroxyl

Alkylpyrazines can be produced by an ingenious sequence involving an electrocyclic ring closure of a 1,4-diazatriene, aromatisation being completed by loss of the oxygen from the original oxime hydroxyl group. ... 

The isomerization of the (Z)-isomer into the ( )-isomer promoted by the iridium complex explains the lack of stereospecificity of the transformation. O-Alkylated oximes and ketoximes do not react and this fact suggests that the presence of both hydrogen and a hydroxyl group is required for the success of the transformation. The authors proposed that the initial displacement of a chloride ion of the iridium complex by the oxime allows the iridium to remove both the oxygen and the hydride from the initial oxime. Swapping places of both substituents produces the amide. 

The ligands (20) contain a coordination site such as pyridyl or amino nitrogen, or a hydroxyl oxygen. Complexes of (20 T = NH2 and n = 2) with iron(II) have been studied recently.65 A copper(II) dimer (with bridging oxime groups) of (20 T = OH, n = 2 or 3) was described by Ablov and coworkers66 in 1972 and its crystal structure has been elucidated67 in 1974. 

If a hapten does not contain free carboxyl, such group(s) may often be introduced. Alkylation of oxygen or nitrogen substituents with halo-esters, followed by hydrolysis of the ester, is frequently used for this purpose (Kabakoff, 1980). For steroids, carboxyl groups may be introduced to the hydroxyl or keton groups, through the formation of hemisuccinate esters or (carboxymethyl)oximes, respectively. 

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