Hydroxylamine ethyl ether

Hydroxylamine [7803-49-8] M 33.0, m 33.1", b 56.5"/22mm. collected by vacuum filtration and washed with cold ethyl ether. 

A regioselective method affording directly 3-phenyl-5-substituted isoxazoles 341, without isolation of isoxazoline intermediates, exploited reactions of NH2OH and a-benzotriazolyl-a,/3-unsaturated ketones 340, stereoselectively generated from benzotriazolylacetophenone and aldehydes in the presence of piperidine (Scheme 83) <2001JOC6787>. Treatment of /3-lithiated benzotriazolylvinyl ethyl ether with acid chlorides followed by cyclocondensation with hydroxylamine hydrochloride gave 4-benzotriazolyl-substituted isoxazoles <2005S245>. 

Hydroxylamine-O-sulfonic acid is a white, hygroscopic, microcrystalline solid, melting with decomposition at 210 to 211°. The solid acid is stable for long periods of time if it is stored in a moisture-free atmosphere, but the compound decomposes very slowly in aqueous solutions below 25°. It is rapidly destroyed in solutions above this temperature. The decomposition is also markedly affected by pH and by the presence of traces of copper ion.4 Decomposition in acidic media yields hydroxylammonium and hydrogen sulfate ions. In alkaline solution the products are nitrogen, ammonia, and sulfate ions. Hydroxylamine-O-sulfonic acid is soluble in cold water and methanol, slightly soluble in ethanol, and insoluble in chloroform, ethyl ether, and carbon tetrachloride. It reacts with ammonia and amines to give hydrazine and substituted hydrazines, respectively. 

Hydrogen peroxide Hydroquinone Hydroquinone ethyl ether 7-Hydroxycoumarin 2-(2 -Hydroxy-3,5 -di-t-amylphenyl) benzotriazole Hydroxyethylcellulose , 2-Hydroxyethyl methacrylate Hydroxylamine sulfate Hydroxypropyl methylcellulose 2-Imidazolidinone... 

Dimethyl glyoxime Dimethyl terephthalate Diphenylamlne Edetic acid Ethyl ether Hydrobromic acid Hydroxylamine Lead molybdate Manganese oxide (ous) Palladium chloride (ous)... 

Another related class to sterically hindered amines are sterically hindered amine ethers. These compoimds are equally capable of forming nitroxyl radicals, as shown in Figure 20.4. Moreover, for example, the ethyl ethers decompose thermally into a hydroxylamine compound and ethene. 

To a solution of 20.8 g. (0.3 mole) of hydroxylamine hydrochloride and 20.6 g. (0.5 mole) of sodium hydroxide (98%) in 100 ml. of water is added 22.26 g. (0.25 mole) of ethyl carbamate. After 3 days at room temperature the solution is cooled in an ice bath and carefully neutralized with concentrated hydrochloric acid (Note 1). If necessary (Note 2), the solution is filtered and then extracted with ether the aqueous phase is evaporated on a water bath under reduced [iressurc as rapidly as possible at a temperature not aliove 50 60 . 

A mixture of unsaturated ethers 119 and 120 obtained from methoxybu-tenyne and diethylcarbonate, when reacted with hydroxylamine in an acidic medium, quantitatively forms the ethyl esters of isoxazolecarboxylic acids 129 (81H146). 

The resulting mixture does not crystalize and is converted into a mixture of oximes by treatment of a solution of the mixture in 20 ml of ethanol with a solution of 1.8 g of hydroxylamine sulfate in 3 ml of water. 1.B g of sodium acetate In 5 ml of water is added, and the mixture is refluxed for 5 hours, then extracted with ethyl acetate, and the ethyl acetate solution is washed with a saturated aqueous sodium chloride solution and dried over Sodium sulfate. After evaporating the solvent, the residue is triturated with warm ether and 1.1 g of a crystalline oxime is obtained, MP 16B° to 171°C. 

Benzenesulphohydroxamic Acid.1—Hydroxylamine hydrochloride (10 g.) is boiled under reflux condenser with just enough methyl alcohol to dissolve it, and when still hot is decomposed by a solution of 3 g. of sodium in 60 c.c. of ethyl alcohol, which should not be added too quickly. After the mixture has been cooled, precipitated sodium chloride is removed at the pump and 8-5 g. of benzenesulphonyl chloride are then added in small portions to the solution of free hydroxylamine. Most of the alcohol is now removed by distillation from the water bath, the hydroxylamine hydrochloride which has separated is removed by filtration, and the filtrate is evaporated to dryness in vacuo at a moderate temperature. The residue is extracted three times with 15 c.c. portions of boiling absolute ether. Evaporation of the combined ethereal extracts in an open dish yields the benzene sulphohydroxamic acid in the form of a mass of crystalline plates which are digested with cold chloroform and filtered with suction. Yield 5-6 g. Melting point 126°. 

Types of compounds are arranged according to the following system hydrocarbons and basic heterocycles hydroxy compounds and their ethers mercapto compounds, sulfides, disulfides, sulfoxides and sulfones, sulfenic, sulfinic and sulfonic acids and their derivatives amines, hydroxylamines, hydrazines, hydrazo and azo compounds carbonyl compounds and their functional derivatives carboxylic acids and their functional derivatives and organometallics. In each chapter, halogen, nitroso, nitro, diazo and azido compounds follow the parent compounds as their substitution derivatives. More detail is indicated in the table of contents. In polyfunctional derivatives reduction of a particular function is mentioned in the place of the highest functionality. Reduction of acrylic acid, for example, is described in the chapter on acids rather than functionalized ethylene, and reduction of ethyl acetoacetate is discussed in the chapter on esters rather than in the chapter on ketones. 

To a sat. soln. of 3-26 grms, of hydroxylamine hydrochloride in anhydrous ethyl alcohol at —5° is added slightly more than the calculated amount of sodium dissolved in the least amount of alcohol. After filtering, 110 c.c. of anhydrous ether and 3 24 grms. of sodium in the minimum amount of alcohol are added to the soln., whioh is then cooled... 

Ethyl acetic acid ether was treated with hydroxylamine and acetohydroxamic acid was obtained. 

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