Oximes


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Oximes

 

aldehyde and ketone derivatives that are obtained upon action of hydroxylamine (H2NOH). Aldoximes have the general formula RHC=N—OH, and ketoximes RR’C=N—OH. Oximes are colorless liquids or crystalline solids with low melting points and low solubility in water but high solubility in organic solvents. Aldoximes and asymmetrical ketoximes occur in two stereoisomeric forms, syn- and anti-. Highly reactive, oximes interact with alkalis to form salts (for example, RR’C=NONa) and hydrolize upon heating with aqueous solutions of mineral acids to yield the original carbonyl compounds—aldehydes and ketones. One important property of ketoximes is their ability to undergo the Beckmann rearrangement—isomerization into the substituted carboxylic-acid amides upon action of acidic dehydrogenating agents. Under similar conditions, aldoximes generally undergo dehydration and subsequent conversion into nitriles.

Oximes form intermediate products during certain syntheses, for example, cyclohexanoneoxime is formed during the preparation of caprolactam, from which nylon-6 fibers are manufactured. Diacetyl dioxime, or dimethylglyoxime, is used in analytical chemistry as a reagent for nickel. One of the methods for quantitatively analyzing aldehydes and ketones is based on the formation of oximes from the salts of hydroxylamines and carbonyl compounds.

References in periodicals archive ?
It is thought to be owing to neuromuscular junction dysfunction and perhaps inadequate oxime therapy.
Cholinesterase reactivation in organophosphorus poisoned patients depends on the plasma concentrations of the oxime pralidoxime methylsulphate and of the organophosphate.
Our proposed strategy was based on a simple and lucid cycloaddition reaction [42-45] of alkyne 5 with oxime 7 to prepare isoxazole-amino acid hybrids 8 (Scheme 1).
For the assessment of oxime and bicarbonate therapeutic regimen, Vucinic et al.13 conducted a clinical trial and suggested that oximes and bicarbonate should not be used together.
Oxime therapy and outcomes in human organophosphate poisoning: An evaluation using meta-analytic techniques.
Oximes of six-membered heterocyclic compounds with two and three heteroatoms: II.
The results were unsuccessful and the oximes unchanged after 30 min of stirring.
Amino acid residues controlling reactivation of organophosphonyl conjugates of acetylcholinesterase by mono- and bisquaternary oximes. J Biol Chem 270:6370-6380.
10:45 SYNTHESIS OF IMINES, ENAMINES AND OXIMES CATALYZED BY SILICA,
The morbidity and mortality with organophosphate poisoning is relatively high despite the use of atropine as specific antidotal therapy and oximes to reactivate acetylcholinesterase Several adjunct and alternative therapies have been explored in animal and human studies.
Role of oximes in organophosphate poisoning--a case report