Hydroxylamine, diazotization

Phenylhydrazine has been prepared by the reduction of benzene diazonium salts with sulfites 1 by the reduction of benzene diazonium chloride with stannous chloride 2 by the reduction of benzene diazonium hydrate with zinc or sulfur dioxide 3 by the reduction of sodium benzene diazotate with sodium stannite 4 by the reduction of diazoamino benzene 5 by the reduction of nitrosophenyl hydroxylamine or its methyl ether 6 and by the action of hydrazine hydrate on phenol.7... 

Oxidation, by chromic-acetic acid, of the hydroxylamine 272 yields the azoxy-thiadiazole 276 quantitatively, presumably via a primary nitrosamine the interaction of the hydroxylamine (272) with suitable nitrosamines does indeed afford mixed azoxy-thiadiazoles (277), but their exact structure is not known. Alkaline hydrolysis of s-azoxy-thiadiazole (276) yields the 1,2,4-thiadiazole diazotate 278 and hydroxy(or alkoxy)-1,2,4-thiadiazole 279, depending on the hydrolytic reagent employed170 (see also ref. 190). 

Veratronitrile has been obtained from 4-aminoveratrole by diazotization and treatment with cuprous cyanide1 and by heating veratrylglyoxylic acid with hydroxylamine.2 The general method employed above has been used for the preparation of a variety of substituted aromatic nitriles.3... 

Two syntheses of benzocinnoline Ar-imines have been described recently.78 They can be prepared from benzocinnoline and hydroxy lamine-O-sulfonic acid or by diazotization of 2,2 -diaminobiphenyl with pentyl nitrite or JV-nitrosodiphenylamine. Diazotization of the diamine presumably proceeds via the triazepine 48, which is isomeric with unsubstituted benzocinnoline iV-imine. Benzocinnoline iV-imine itself, the only unsubstituted iV-imine so far isolated, was prepared from benzocinnoline and hydroxylamine-O-sulfonic acid. Under similar conditions, quaternary IV-amino salts were isolated from the other iV-heterocycles. The unsubstituted Ar-imine can be converted easily into the acyl, sulfonyl, and 2,4-dinitrophenyl derivatives (Scheme 3). 

The hydroxylamine is oxidized to nitrite with an acidic iodine solution and the excess iodine destroyed by arsenite. The nitrite thus produced is determined by diazotizing sulphanilic acid and coupling with N-( 1-naphthyl)-ethylenediamine to form a highly coloured azo dye, the extinction of which is measured. A correction is made for any nitrite initially present in the sample. 

Hydroxylamine, oximes, and hydroxamic acids can be oxidized with iodine quantitatively to nitrous acid. If this oxidation takes place in the presence of sulfanilic acid, the latter is diazotized so that it can be detected, after the excess of iodine had been eliminated with thiosulfate, by coupling it with 1-naphthylamine. 

A series of 8-amlnopurine nucleosides and their N -substituted derivatives were prepared via direct brominatlon of the natural purine ribosides and deoxyribosides and subsequent nucleophilic displacement of the 8-bromo group with hydrazine or azide (followed by catalytic reduction), hydroxylamine or allqrlamines . A new synthesis of 2-fluoro-adenoslne was developed, starting from 2,6-diazido-9-(tri-0-acetyl-p-D-ribofuranosyl)purine which was reduced to the 2-amlno-adenosine derivati the latter was selectively diazotized in the presence of fluoroboric acid 2. 2-Fluoro-3 -deoxyadenpsine was prepared from the unprotected 2-amlno-3 -deoxyadenosine in an analogous manner . 2-Aminoadenosine was also prepared by Raney-nickel catalyzed reduction of 2,6-dihydroxylamino-... 

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