2-hydroxy oximes

Long range functionalization of alcohols via nitrites leading to y-hydroxy oximes... 

The further transformation of hydroxy oximes to the nitrone has been observed with llj5-hydroxy-l 8-oximes after thermal treatment or by... 

The second example is the extraction of Ni(II) with 2-hydroxy oxime. 2-Hydroxy oxime including 5-nonylsalicylaldoxime (P50) [15], 2-hydroxy-5-nonylacetophenone oxime (SME529) [16], and 2-hydroxy-5-nonylbenzophenone oxime (LIX65N) [17], are widely used as commercial extractants of Ni(II), Cu(II), and Co(II) in hydrometallurgy. These extractants are adsorbed at the interface even in their neutral forms following the Langmuir isotherm,... 

The adsorptivity and the reactivity of the 2-hydroxy oxime were well simulated by the MD simulations as shown in Fig. 5 where the polar groups of — OH and = N — OH of the adsorbed LIX65N molecule are accommodated in the aqueous phase so as to react with Ni(II) ion in the aqueous phase [18], This is the reason why the reaction rate constants of Ni(II) at the interface have almost same magnitude as those in aqueous phase. 

TABLE 1 Parameters in the Adsorption and Extraction of Ni(II) with 2-Hydroxy Oxime in Heptane-0.1 M(H,Na)C104 at 25°C... 

The history and chemistry of the hydroxy-oxime extractants which were originally developed for Cu recovery has been extensively reviewed.11,13,14 Szymanowski s book14 provides comprehensive cover of the literature prior to 1993 and assigns chemical structures to reagents which in most metallurgy texts are referred to only by codes provided by reagent suppliers. An updated version of this information is provided in Table 3. 

Hydroxy-, oxime-, hydroxamate- and imidazole-functionalized micelles. Rate comparisons... 

Generally, hydrogenolysis involves cleavage of the endocyclic N—O bond as the first step. For example, four-membered cyclic nitronates can be reduced successively to a-hydroxy-oximes (167) (Scheme 3.116, Eq. 1). Unfortunately, the yield of the target product was not reported. 

If the alkoxy group at the C-6 atom in nitroso acetals (475) is absent, silyl derivatives (476) are generated instead of nitroso ketones A, and methanolysis of compounds (476) gives rise to y-hydroxy oximes (479). 

Main Rearrangements of BENA In previous Sections (3.5.4.1. and 3.5.4.2.), a-hydroxy oximes (503) and their bis-silyl derivatives (504) were considered as undesired by-products, formed in the synthesis and chemical transformations of BENA. The aim was to minimize the amount of these impurities. On the other hand, oximes (503) are convenient precursors of various useful products, such as p-amino alcohols (530), amino acids (531), a-hydroxycarbonyl compounds (532) and various heterocyclic systems (533). 

The second selective extractant route (that of MRR) uses a hydroxy-oxime to remove palladium. The actual compound used has not been specified, but publications refer to both an aliphatic a-hydroxyoxime and an aromatic S-hydroxyoxime. The a-hydroxyoxime LIX63 has the faster extraction kinetics, but suffers from problems with stripping. For the (i-hydroxyoxime, a kinetic accelerator in the form of an amine (Primene JMT ) has been proposed. The precise mode of operation of this accelerator is unknown, but it may be a similar process to that proposed for the sulfide... 

The D-ring of steroids has been cleaved frequently by a Beckmann fragmentation. Typical strategy uses enolate chemistry to introduce an oximino group at the a-carbonyl carbon. Reduction of the carbonyl (or addition of a carbanion) produces an a-hydroxy oxime which serves as good substrate for the fragmentation. Two examples of this strategy are shown in equations 213 and 214. 

Conversion of the keto ketoxime 1 to the exo-exo-amino alcohol 2 has been accomplished by hydrogenation over Adams catalyst and by reduction with lithium aluminum hydride. Amino alcohol 2 has also been prepared from 1 by a two-stage process in which selective reduction of the ketone is carried out with sodium borohydride, and the resultant hydroxy oxime is reduced with lithium aluminum hydride or by hydrogenation over Adams catalyst. ... 

Beckmann fragmentation of the hydroxy-oxime (119) gave the 16,17-seco-compound (120) which can be converted, by NaBH4 reduction and acid hydrolysis, into the lactone (121). The lactone (121) may also be obtained directly upon acidification of the reaction mixture from heating the hydroxy-oxime (119) with... 

Cleavage of the isoxazolidine ring can also be effected directly to give similar products as the isoxazoline. Upon the addition of methoxide to an isoxazolidine bearing a hydrogen at C(3), fragmentation reveals a p-hydroxy oxime, which can be further hydrolyzed to the corresponding ketone (16,20,34,108). The P-hydroxy... 

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