Oximes chemical

Hydroxybenzaldehyde has extensive use as an intermediate in the synthesis of a variety of agricultural chemicals. Halogenation of Nhydroxybenzaldehyde, followed by conversion to the oxime, and subsequent dehydration results in the formation of 3,5-dihalo-4-hydroxybenzonitrile (2). Both the dibromo- and dhodo-compounds are commercially important contact herbicides, hromoxynil [1689-84-5] (2) where X = Br, and ioxynil [1689-83-4]( where X = I respectively (74). Several hydrazone derivatives have also been shown to be active herbicides (70). 

The products have the characteristic lemon odor of citral and also have greater odor strength and chemical stabiUty than citral. As the need for more stable citms-like fragrances for use in bleach developed, other nitrile compounds have been made available commercially. CitroneUyl nitrile is made from citroneUal dimethyloctanenitrile is produced from dimethyloctanal by the oximation method. 

Although the activity of methoxylated monobactams could be improved by appropriate side-chain modifications, difficulty of synthesis and poor chemical stabihty focused attention on the nonmethoxylated analogues. Both high intrinsic activity and excellent P-lactamase stabiUty are exhibited by monobactams that combine C-3 arninothia2ole oxime side chains and 4-alkyl, 4-alkenyl, and 4-alkynyl groups (19). 

Other macrohdes have been prepared which represent hybrids of stmctures within the 14-membered family, within the 16-membered family, or between the two families. These hybrids have been made by chemical, bioconversion, or genetic manipulations. The 9-0-[(2-methoxyethoxy)methyl]oxime of tylosin (Table 7) was synthesized, using the oxime found in roxithromycin (33) (369). 3-0-Cladinosyl derivatives of 16-membered macrohdes were synthesized in which the neutral sugar of erythromycin (Table 3) was attached to tylosin derivatives at thek 3-hydroxyl group, analogous to its position in erythromycin... 

Caprolactam [105-60-2] (2-oxohexamethyleiiiiriiQe, liexaliydro-2J -a2epin-2-one) is one of the most widely used chemical intermediates. However, almost all of the aimual production of 3.0 x 10 t is consumed as the monomer for nylon-6 fibers and plastics (see Fibers survey Polyamides, plastics). Cyclohexanone, which is the most common organic precursor of caprolactam, is made from benzene by either phenol hydrogenation or cyclohexane oxidation (see Cyclohexanoland cyclohexanone). Reaction with ammonia-derived hydroxjlamine forms cyclohexanone oxime, which undergoes molecular rearrangement to the seven-membered ring S-caprolactam. 

The most important use of cyclohexanone is as a chemical intermediate in nylon manufacture 97% of all cyclohexanone output is used either to make caprolactam for nylon-6, or adipic acid for nylon-6,6. In the caprolactam process cyclohexanone is converted to cyclohexanone oxime (mp,... 

Particular reactions can occur in either or both phases or near the interface. Nitration of aromatics with HNO3-H2SO4 occurs in the aqueous phase (Albright and Hanson, eds.. Industrial and Laboratoiy Nitration.s, ACS Symposium Series 22 [1975]). An industrial example of reaction in both phases is the oximation of cyclohexanone, a step in the manufacture of caprolactam for nylon (Rod, Proc. 4th Interna-tional/6th European Symposium on Chemical Reactions, Heidelberg, Pergamon, 1976, p. 275). The reaction between butene and isobutane... 

Ultraviolet and infrared spectroscopic investigations and also chemical behavior show unambiguously that the compounds which result from the last-rnentioned type of nucleophilic reagent and cotarnine possess the cyclic form. " Examples of these are cotar-nine anil (20a), cotarnine oxime (20b), cotarnine phenylhydra-zone (20c), anhydrocotarnine carbamide (20d), hydrocotarnyl-acetic acid (20e), anhydrocotarnine acetone (20f), and also the compound (21) obtained from two molecules of cotarnine and one molecule of acetone by the elimination of two molecules of water. The cyclic form had ben demonstrated earlier for anhydrocotarnine-nitromethane (20g) and anhydrocotarnine-acetophenone (20h). ... 

Chemical Name 5H-Dibenzo[a,d] cyclohepten-5-oneO-[2-(methylamino)ethyl] oxime Common Name —... 

Chemical Name 5-Methoxy-4 -trifluoromethylvalerophenone 0-(2-aminoethyl)oxime maleate (1 1)... 

Chemical Name 10,11-dihydro-5H-diben2o[a,d] cyclohepten-5-one 0-[2-(dimethylamino)-ethyl] oxime... 

Chemical Name 1 -(2,4-Dichlorophenyl)-2-( 1 H-imidazol-1 -yl)-0-(2,4-dichlorobenzyl)-ethanone oxime nitrate... 

When modified fibres of type 5 are treated with hydroxylamine, oxime groups are also easily formed. The interaction with a protein affords a sandwich polymer22. Fibres modified in this way have enhances dyeability. When copolymer fibres are treated with diamine solutions or in acid medium with Fe+3 salts, intermolecular chemical bonds are formed, which results in a considerable increase of the temperature of zero strength and of the heat resistance of fibres. These conversions are shown in Scheme 2. 

Oxime carbamates have high polarity and solubility in water and are relatively chemically and thermally unstable. They are relatively stable in weakly acidic to neutral media (pH 4-6) but unstable in strongly acidic and basic media. Rapid hydrolysis occurs in strongly basic aqueous solutions (pH > 9) to form the parent oxime/alcohol and methylamine, which is enhanced at elevated temperature. Additionally, oxime carbamates are, generally, stable in most organic solvents and readily soluble in acetone, methanol, acetonitrile, and ethyl acetate, with the exception of aliphatic hydrocarbons. Furthermore, most oxime carbamates contain an active -alkyl (methyl) moiety that can be easily oxidized to form the corresponding sulfoxide or sulfone metabolites. 

Table 1 Chemical names and properties of selected oxime carbamates... 

Oxime carbamates are generally stable in aqueous solutions at pH 4-6. Their chemical degradation (hydrolysis) in water depends strongly on pH. Strongly basic conditions... 

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. 

Machiguchi, Nozoe and coworkers have very recently observed that in contrast to chemical reactivity of tropones, the tosylate of tropone oxime undergoes a facile ring-opening to 6-substituted (Z,Z,Z)-1,3,5-hexatriene nitriles on reaction with various nucleophiles305. For example, reaction of phenyl lithium results in the corresponding hexatriene carbonitrile (equation 183). 

Reactive oximes and their salts, such as potassium 2,3-butanedione monoximate found in commercially available Reactive Skin Decontaminant Lotion (RSDL), are extremely effective at rapidly detoxifying sulfur vesicants. Some chloroisocyanurates, similar to those found in the Canadian Aqueous System for Chemical-Biological Agent Decontamination (CAS-CAD), are effective at detoxifying sulfur vesicants, and so is oxone, a peroxymonosulfate triple salt. 

The agents in this class are halogenated oximes. This class of agents is not specifically covered by the Chemical Weapons Convention. Because of the toxicity of the agents and lack of commercial application outside of limited scientific research, urticants would be prohibited based on the Guidelines for Schedules of Chemicals. 

These shifts are similar to the 29Si chemical shifts in the spectra of silyl derivatives of analogous oximes. This is evidence for the absence of essential additional coordination of silicon in SENAs. The qualitative and quantitative analyses of the 29Si NMR signal can be considered as a simple method of NMR monitoring of SENAs in solution. 

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). 

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