Those derived from aldehydes are known as aldoximes, those from ketones as ketoximes.
The aldoximes are converted by the action of dehydrating agents into nitriles: RCH: NOH-->R C: N+H 2 0.
Thus in the case of the simple aldoximes two con R C H R C H figurations are possible, namely: and
, the former, N OH HO N where the H atom and OH group are contiguous, being known as syn-aldoximes and the latter as the anti-aldoximes.
The syn-aldoximes or treatment with acetyl chloride readily lose water and yield nitriles; the anti-aldoximes as a rule are acetylated and do not yield nitriles.
HO N Aldoximes are generally obtained by the action of hydroxylamine hydrochloride on the aldehyde in presence of sodium carbonate; the oxime being then usually extracted from the solution by ether.
Ketoximes are usually rather more difficult to prepare than aldoximes, and generally require the presence of a fairly concentrated alkaline solution.
-> CH3C6H5CONHC6H51 N OH Syn-phenyltolylketoxime CH3 C6H4 C C6H5 CH3C6H4NH000,H5 HO N A nti-tolylphenylketoxime In the case of the aldoximes, that one which most readily loses the elements of water on dehydration is assumed to contain its hydroxyl radical adjacent to the movable hydrogen atom and is designated the syn-compound.
They react with hydroxylamine and phenylhydrazine, with the formation of aldoximes and hydrazones.
(For the isomerism of the aldoximes see Ox1MES).
Soc. chim., 18 95, (3) 1 3, p. 735); and from the syn-aldoximes by the action of acetyl chloride or acetic anhydride.