Hydroxylamine using

Addition of arylhydroxylamines to electrophilic allenes such as methyl propadienoate or l-methancsulfonyl-l,2-propadiene is another route to 0-vinyl derivatives[2]. The addition step is carried out by forming the salt of the hydroxylamine using NaH and the addition is catalysed with LiO CCFj. The intermediate adducts are cyclized by warming in formic acid. Yields are typically 80% or better. 

Although the simplest route to prepare hydroxamic acid derivatives remains the reaction of hydroxylamine with acid chlorides, this last method cannot be apphed to all Af-protected-a-amino acids. The synthesis of Fmoc-protected amino acid hydroxamates represents the only exception to this rule . In fact, Fmoc-amino acid hydroxamates 98 can be synthesized by the acylation of hydroxylamine using Fmoc-amino acid chlorides 97 in the presence of MgO (Scheme 52). The route is simple, efficient, and affords good yields of products. 

Treatment of V-acyloxazolidinone 122 with hydroxylamines using samarium triflate as a Lewis acid gives the corresponding hydroxamic acids 123 in 50-98% yields at room temperature (Scheme 61). The conversion proceeds with a high degree of chemoselectivity and without racemization of chiral centers at the a-position to the acyl group. 

Antidotes that remove active poison from its site of action e.g. hydroxylamine used in organophosphate anticholinesterase poisoning. 

In a similar way it is possible to perform the amination of aromatics by indirect electrochemical reduction of hydroxylamine using a combination of the Cu /Cu and redox pairs Thus, aniline and toluidine are formed from benzene... 

The electrical conductivity was measured by W. H. Ross, who found that in all cases the conductivity of the salt soln. was increased with time, especially with the more dil. soln. This is due to the decomposition of the salts under the influence of the platinum-black of the electrodes with polished electrodes, the effect is considerably smaller. The base itself is oxidized even more rapidly than the salts. The soln. are in all cases decomposed by the platinum electrodes, and G. M. J. MacKay showed that tin does not decompose the soln. at all, while copper decomposes the soln. completely. The order in which the metals were found to decompose the soln. is tin, platinum, silver, nickel, mercury, and copper. The electrical conductivity of hydroxylamine, using tin electrodes, in terms of mercury at 18°, with v vols. of soln. per mol, is as follows ... 

Treatment of A-acyloxazolidinones with hydroxylamines using samarium triflate as a Lewis acid, afforded the corresponding hydroxamic acids in good yields <02OL3343>. 

In this pyridine synthesis, give a structure for A and mechanisms for the reactions. Why is hydroxylamine used instead... 

Eve, T.S.C., Wells, A. and Turner, N.J. (2007) Enantioselective oxidation of 0-methyl-hydroxylamines using monoamine oxidase N as catalyst. Chemical Communications, 1530-1531. 

Metals bound to Fe-Mn oxides determined together. Sulfide or sulfide-ocduded metals. Bound to free and readily soluble oxides. Calculated as difference between the total content and sum of other operational groups. Symbols HOAc, acetic add HO, oxalic acid NH4OAC, ammonium acetate NH4OJ, ammonium oxalate NHjOH, hydroxylamine used as NHjOHHCl NaOAc, sodium acetate DTP A, diethylenetriaminepentaacetic acid EDTA, efhylenediaminetetraacetic add (sodium salt) CBD, dtrate-bicarbonate-dithionite Hq, hydroquinone TEA, triethanolamine Fx, numbers of operational groups (fractions, species) of metals, as defined by the authors. In both procedures FI fraction is related to water soluble form of the elements. 

The hydroxylamine used for the reaction with cyclohexanone is obtained by the Raschig process or by catalytic hydrogenation of either nitric oxide or nitric add. In the Raschig process, the hydroxylamine is obtained in the form of its sulfate. The raw materials for this process are sulfur dioxide, ammonia, carbon dioxide, and water. A mixture of NO and NO2, as obtained from the catalytic oxidation of ammonia, is absorbed in an aqueous ammonium carbonate solution to yield ammonium nitrite, which is then reacted with SO2 in the presence of ammonium hydroxide. The product of this reaction is hydroxylamine disulfonate, which converts upon hydrolysis via the monosulfonic acid hydroxylamine into hydroxylamine sulfate ... 

Table 7.8. Electrochemical Data for the Electrocatalytic Detection of Hydrazine and Hydroxylamine Using M-N4 Complexes ... 

Scheme 6.3 Three-component protocol for determination of the e.e. values of chiral hydroxylamines using the assembly of boronic acid and enantiopure BINOL. ...

It has been shown that during the synthesis of the nitrile 124 by free radical chemistry (Vol. 22, p. 214), some of the C-3 epimer is also formed. 156 Nitrile 124 was used in an alternative route to 3 -deoxy-3 -C-hydroxymethylthymidine 125 (see Vol. 25, p. 257) Mitsunobu reaction with N-hydroxyphthalimide at the branched hydroxymethyl group gave an (9-alkyl hydroxylamine used to make the dinucleotide analogue 91 (see Section 6). 126 The 3 -aldehyde formed as an intermediate in... 

Form Supplied in liquid widely available, but expensive. Analysis of Reagent Purity FI NMR (benzene- s) 0.16 (s, 9, NSiMes), 0.25 (s, 9, OSiMes), 4.6 (br s, 1, NH).i 3 Preparative Methods can be prepared in 69% yield by treating dry hydroxylamine with 2 equiv chlorotrimethylsilane and 2 equiv triethylamine. A safer preparation, which avoids the use of the explosive solid, hydroxylamine, uses the reaction of hydroxylamine hydrochloride with excess hexamethyldisi-lazane (71-75% yield).Alternatively, neutralization of hydroxylamine hydrochloride with ethylenediamine followed by addition of chlorotrimethylsilane can be used. ... 

Chain extenders are usually difunctional compounds, such as glycols, diamines or hydroxylamines used in polyureas and polyurethane/ureas. Table 7 shows common hydroxylated compounds used as chain extenders or crosslinkers. 

In the DSM HPO process, nitrate ions are reduced to hydroxylamine using a palladium/carbon catalyst in an aqueous phosphate buffer solution. It was possible to prepare cyclohexanone oxime by a process involving the extraction of cyclohexanone from solution in toluene, into an immiscible aqueous solution of hydroxylamine in a two phase liquid reactor. The spent solution was then recycled with added nitric acid to the reduction step and sulfate production was eliminated ... 

---