Raman spectrum of hydroxylamine hydrochloride (NH3OH.Cl)

The Raman spectrum of hydroxylamine hydrochloride (NH3OH.Cl) in the form of a single crystal has been photographed usingλ 2536·5 excitation. 32 Raman lines with frequency shifts 40, 57, 78, 88, 111, 125, 135, 156, 187, 217, 250, 330, 550, 575, 1004, 1168, 1204, 1470, 1496, 1565, 1590, 1979, 2636, 2710, 2750, 2789, 2926, 2970, 3000, 3050, 3141 and 3220 cm.−1 have been recorded. Of these, the first 8 low-frequency lines belong to the external oscillation, while the four lines at 187, 217, 250 and 330 cm.−1 should be attributed to the vibrations of the hydrogen bond valence vibrations. The remaining Raman lines have been assigned to the vibrations of the NH3OH ion. The O-H and N-H stretching vibrations are very much influenced by the presence of the hydrogen bonds in the crystal.

Reaction of spironaphthalenones with hydroxylamine: Part I. A reinvestigation of the mechanism

Spironaphthalenones 1b–g on reaction with hydroxylamine hydrochloride gave the expected pyrrolotropones 2b–g. Furanotropone 6, postulated as an intermediate in the formation of pyrrolotropones, remained unchanged on reaction with hydroxylamine hydrochloride in ethanol. Reaction of unsymmetrical spironaphthalenones 1h–o with NH2OH.HCl gave the rearranged pyrrolotropones 2h–o.

Reaction of spironaphthalenones with hydroxylamine: Part II. Structure of product in the reaction of 1′-substituted spironaphthalenone.

Reaction of 1′-aryl substituted spironaphthalenones 1a–d with hydroxylamine hydrochloride in ethanol gave substituted cinnamic ester derivatives 4a–d. Similarly, reaction of spironaphthalenone 1a with different alcohols gave the corresponding esters 4i–m. Reaction of unsymmetrical spironaphthalenones 1e–h with hydroxylamine hydrochloride in presence of ethanol gave the respective esters 4e–h. All the esters were characterised by their spectral data.

Reaction of spironaphthalenones with hydroxylamine: Part III. A novel mechanism for the formation of products and trapping of an intermediate.

A mechanism involving the intermediacy of nitrene 5, formed from the oxime of spironaphthalenone 1 by acid catalysed dehydration, has been proposed to explain the formation of pyrrolotropones/pyrrolo esters from spironaphthalenones. The initially formed nitrene rearranges to the isopyrrole 6, which either undergoes sigmatropic migration to the pyrrolotropone 2 or adds alcohol to form the pyrrolo ester depending on substitution at 1′ position. The isopyrrole intermediate 6 has been trapped as a Diels-Alder adduct 8.

Reaction of spironaphthalenones with hydroxylamine hydrochloride: Part IV

Reaction of 1-methoxynaphthalene with 1-formylnaphthalene in presence of n-BuLi/TMEDA, followed by deoxygenation and demethylation gave the bisnaphthol 6. Oxidation of 6 with KOBr yielded the spironaphthalenones 4a-b and 5a-b. The spironaphthalenones 3a-c on reaction with NH2OH.HCl gave naphth[2,1-c]isoxazole derivatives 9a-c. While similar reaction of 4a-b gave the pyrrolotropones 11a-b, spironaphthalenones 5a-b afforded the naphth[1,2-c]isoxazole derivatives 12a-b.

Phosphorus substituted hydroxylamine and hydroxamic acid derivatives: synthesis and reactivity

Dedicated to Prof. Julio Alvarez-Builla on the occasion of his 65th anniversary.

Control of cocklebur seed germination by nitrogenous compounds : Nitrite, nitrate, hydroxylamine, thiourea, azide and cyanide

Germination of non-dormant upper cocklebur (Xanthium pinsylvanicum Wallr.) seeds was stimulated by not only CS(NH2)2 but also NH2OH, KCN and NaN3. This stimulation was not via the enhancement of aerobic C2H4 production. NH2OH, KCN and NaN3 in certain concentrations promoted the initial growth of axial and/or cotyledonary parts, but the degree of growth promotion by NH2OH, NaN3 and KCN was slight compared with that by CS(NH2)2. As in the case of CS(NH2)2, however, the germinationstimulating effect of NH2OH disappeared rapidly as the preceding imbibition period was prolonged. In contrast, KCN and NaN3 were still effective in stimulating the germination of aged seeds maintained on a water substratum, as previously seen with anaerobiosis. Anaerobic induction was enhanced not only by NaN3 and KCN but also by NH2OH, KNO3, KNO2 CO(NH2)2 and CS(NH2)2 applied during the anaerobic treatment, but without causing an increase in anaerobic production of C2H4. Furthermore, KCN and NaN3, given prior to the anaerobic treatment acted additively with anaerobic induction. The germination-stimulating actions of nitrogenous compounds are discussed in comparison with those of C2H4 and anaerobiosis.

Determination of hydroxylamine by capillary electrophoresis electrochemical detection with a palladium-particle modified carbon fiber microdisk array electrode

A highly dispersed ultramicro palladium-particle modified carbon fiber microdisk array electrode (Pd-CFE) was employed for capillary electrophoresis-electrochemical (CEEC) detection of hydroxylamine (HA). The Pd particles obtained were in the nanometer scale, had a high electrocatalytic activity towards HA and exhibited good reproducibility and stability. A linear relationship between the current and the analyte concentration was found between 5 x 10(-6) and 1 x 10(-3) mol/l of HA with a correlation coefficient of 0.9992. The detection limit was 5 x 10(-8) mol/l. The applicability of the method for the determination of HA in river water and waste water was investigated.

The inhibition of human cytomegalovirus (hCMV) protease by hydroxylamine derivatives.

Aryl hydroxylamine derivs. have been synthesized that are some of the most potent inhibitors of hCMV protease prepd. to date (IC50 14-60 nM). Mass spectrometry studies indicate that oxazinone derived hydroxylamines inhibit the enzyme by acylation of Ser132 whereas non-oxazinone derived hydroxylamines appear to inhibit via formation of a sulfinanilide at Cys138.

Electrochemical Oxidation of Hydroxylamine on Gold in Aqueous Acidic Electrolytes: An in Situ SERS Investigation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The Oxidation of Hydroxylamine on Gold Electrodes in Mildly Acidic Aqueous Electrolytes: Electrochemical and In Situ Differential Reflectance Studies

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The oxidation of hydroxylamine on Pt-, and Pd-modified Au electrodes in aqueous electrolytes: Electrochemical and in situ spectroscopic studies

The electrooxidation of hydroxylamine, NH2OH, in 0.1 M phosphate buffer (PB, pH = 7) on Pt-, and Pd-modified Au electrodes prepared by galvanic displacement of underpotential deposited Cu, was investigated by electrochemical techniques and three and in situ vibrational probes, substrate-induced surface enhanced Raman scattering, SI-SERS, surface enhanced infrared absorption, SEIRAS, and Fourier transform infrared reflection-absorption, IRAS, spectroscopies. Analyses of the results obtained made it possible to identify at low overpotentials, solution phase (sol) and adsorbed (ads) nitric oxide, NO, as well as solution phase nitrous oxide, N2O. As the potential was increased, the peak(s) ascribed to NO(ads) gained in intensity and new features associated with NO2−(ads) and NO2−(sol) were clearly discerned. Further excursion toward higher potentials yielded an additional peak assigned to NO2(ads). This behavior is analogous to that found for bare Au electrodes in a potential region in which the metal is at least partially oxidized under otherwise the same experimental conditions.