HYDROXYLAMINE.172 PHOSPHORUS PENTACHLORIDE

In the mildest of these reactions the hydroxylamine is refluxed in ether over phosphorus pentachloride and the same order of migration aptitudes is observed as in the pinacol rearrangement. The range in... 

For example, the chloramine LV failed to rearrange when heated with base, a condition not unfavorable for the non-chain radical mechanism.812 Yet the corresponding hydroxylamine rearranged with phosphorus pentachloride in ether.813... 

Xanthone is unreactive towards hydrazine and phenylhydrazine. The oxime is obtained by reaction of xanthione (xanthene-9-thione) with hydroxylamine, or from xanthone and hydroxylamine in pyridine. When the oxime is heated in water with phenylhydrazine, the phenylhydrazone is formed. In acid solution, xanthone reacts normally with 2,4-dinitro-phenylhydrazine but xanthone-1 -carboxylic acid (435) gives the pyridazinone (436), possibly via the hydrazone (57JCS1922). When the oxime is heated with phosphorus pentachloride it undergoes a Beckmann rearrangement to give the amide (437) (70MI22300). 

Dehydropregnenolon-3p-acetate Hydroxylamine hydrochloride Phosphorus pentachloride... 

To a solution of 1 gram of 16-dehydropregnenolon-3p-acetate in 10 ml pyridine is added 0.22 gram of hydroxylamine hydrochloride, and the mixture is allowed to stand at room temperature for four days. One gram of 16-dehydropregnenolon-3p-acetate oxime is dissolved in 30 ml of hot dioxane, and then the solution is cooled in an ice bath until about one-half of the dioxane has solidified. Then 1 gram of phosphorus pentachloride is added and the mixture is shaken until all the dioxane has melted. The mixture is maintained at 35°C, for seventy-five minutes, then an excess of ice is added and the solution is again allowed to stand at 35°C. After about thirty minutes, a solution of 5 ml of concentrated hydrochloric acid in 10 ml of water is added, and the mixture is diluted with water, extracted with ether and the ethereal extract washed with dilute sodium hydroxide solution. The ether is removed on a steam bath and the residue is worked up to yield dehydro-isoandrosterone. 

Camphor, CioHieO, sometimes called Japan camphor or laurinol, is obtained by distilling with steam the wood or leaves of the camphor tree it melts at 176°-177°, boils at 209 , and is dextro-rotatory. The chemical properties of camphor are those of a ketone it forms an oxime with hydroxylamine, its oxygen atom is replaced by two chlorine atoms when it is treated with phosphorus pentachloride, and it is converted by reducing agents into borneol, which is a secondary alcohol. By the loss of water camphor passes into cymene (453), and by... 

Rearrangement of trityl hydroxylamines to Schiff bases on treatment with phosphorus pentachloride ... 

Fresenius, passing his pharmacy examination in 1877. He then joined Kolbe, and his assistant, Ernst von Meyer, and started work on the oxidation of dialkyl sulfides. For this research Beckmann received his PhD in July 1878. Beckmann tried to apply an already-known reaction to discriminate between aldehydes and ketones. This reaction involved the use of hydroxylamine to convert benzophenone into an oxime. Treating this oxime with phosphorus pentachloride he converted it into a substance already characterized by Wallach. This reaction is now known as the Beckmann rearrangement. 

Hydroxylamine Barium oxide and peroxide, carbonyls, chlorine, copper(II) sulfate, dichromates, lead dioxide, phosphorus trichloride and pentachloride, permanganates, pyridine, sodium, zinc... 

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