Hydroxylamines reacting with ketones

Ketones and aldehydes also condense with other ammonia derivatives, such as hydroxyl amine and substituted hydrazines, to give imine derivatives. The equilibrium constants for these reactions are usually more favorable than for reactions with simple amines. Hydroxylamine reacts with ketones and aldehydes to form oximes hydrazine and its derivatives react to form hydrazones and semicarbazide reacts to form semicarbazones. The mechanisms of these reactions are similar to the mechanism of imine formation. 

Hydroxylamine reacts with ketones and aldehydes to form oximes hydrazine deriva- With HydrOXylamine tives react to form hydrazones and semicarbazide reacts to form semicarbazones. The H VdrazineS... 

Oxime. Hydroxylamine reacts with aldehydes and ketones to form oximes. 

Hydroxylamine, NH2OH Reacts with ketones and aldehydes to yield oximes (Section 19.8). 

Aldehydes and ketones can be differentiated from noncarbonyl compounds through their reactions with derivatives of ammonia (Section 16.8B). 2,4-Dinitrophenylhydrazine and hydroxylamine react with aldehydes and ketones to form precipitates. Oximes are usually colorless, whereas 2,4-dinitrophenylhydrazones are usually orange. The melting points of these derivatives can also be used in identifying specific aldehydes and ketones. 

Hydrazine reacts with aldehydes and ketones to give hydra-zones. Hydrazone derivatives react with aldehydes and ketone to give AT-substituted hydrazones. Hydroxylamine reacts with aldehydes and ketones to give oximes. Semicarbazone reacts with aldehydes and ketones to give semicarbazides. 

Several useful nitrogen-containing molecules react with ketones or aldehydes in a manner that is similar to the reaction of primary amines. Hydroxylamine (96) is essentially a functionalized amine, as is hydrazine (97)—an important compound that was used as rocket fuel many years ago. Hydrazine is still used as a propellant on board space vehicles and in satellites in order to make course corrections. Hydroxylamine may be explosive when concentrated, and shordd be handled with care, but it is used for the removal of hair from animal hides and in photographic developing solutions. ... 

Hydroxylamine reacts with aldehydes or ketones to yield an oxime (Eq. 25.24). Hydroxylamine is usually stored as the hydrochloric acid salt because it is not stable as the free base it is liberated from its salt by addition of base. The use of an oxime as a derivative has the limitation that such compounds frequently are not crystalline solids. 

For the second step, recall that primary amines react with ketones reversibly to furnish imines by loss of water (Section 17-9) and that, in fact, hydroxylamine makes oximes (Table 17-5). These condensations proceed through the intermediacy of hemiaminals by nucleophilic attack of the amine nitrogen on the carbonyl carbon. 

The purity of a synthetic preparation of methylethyl ketone (C4H8O) can be determined by reacting the ketone with hydroxylamine hydrochloride, liberating HCl (see Table 9.10). In a typical analysis, a 3.00-mL sample was diluted to 50.00 ml and treated with an excess of hydroxylamine hydrochloride. The liberated HCl was titrated with 0.9989 M NaOH, requiring 32.68 ml to reach the end point. Report the percent purity of the sample, given that the density of methylethyl ketone is 0.805 g/mL. 

Diphenylthiirene 1-oxide reacts with hydroxylamine to give the oxime of benzyl phenyl ketone (79JA390). The reaction probably occurs by addition to the carbon-carbon double bond followed by loss of sulfur monoxide (Scheme 80). Dimethylamine adds to the double bond of 2,3-diphenylthiirene 1,1-dioxide with loss of sulfur dioxide (Scheme 81) (75JOC3189). Azide ion gives seven products, one of which involves cleavage of the carbon-carbon bond of an intermediate cycloadduct (Scheme 81) (80JOC2604). 

The reaction of 2-chloro-4,5-dihydroimidazole 347 with hydroxylamine-O-sulfonic acid gives 2-hydroxylamino-4,5-dihydroimidazolium-O-sulfonate 348, which reacts with aldehydes and cyclic ketones to give the imidazo[l,2-f] fused 4,5-dihydro-l,2,4-oxadiazoles 350 (Scheme 58). Mechanistically, the reaction may be explained by the reaction of an imidazoline NH with the carbonyl followed by intramolecular electrophilic amination of the anionic oxygen present in the resultant intermediate 349 and elimination of the sulfate group <2003JOC4791>. 

Cyclocondensation processes of p-dicarbonyl derivatives or their analogues are still widely employed for the synthesis of new isoxazoles. Non-proteinogenic heterocyclic substituted ct-amino acids have been synthesised using the alkynyl ketone functionality as a versatile building block ynone 2, derived from protected L-aspartic acid 1, reacted with hydroxylamine hydrochloride affording the isoxazole 3 with enantiomeric purity greater than 98% ee <00 JCS(P 1 )2311 >. 

In 1983, Prasad et al.12 first reported the condensation of chloromethyl polystyrene with /V-hydroxyphthalimide to give the ester, hydrazinolysis of which yielded the desired resin-bound hydroxylamine. However, the sole purpose of this reagent was to react with, and hence extract ketones from, a complex steroidal mixture, and its use for the solid-phase synthesis of hydroxamic acids was not explored. Recently, the exploitation of the above solid-phase approach for the synthesis of hydroxamic acids was independently reported by three groups,7-9 all of which differ only in the method for the initial anchoring of TV-hydroxyphtha-limide to an 4-alkoxybenzyl alcohol functionalized polystyrene or trityl chloride polystyrene. Subsequent /V-deprotection was... 

In 1999, Hajipour reported that silica gel, without any base, could be a useful catalyst for the preparation of oximes in dry media coupled with microwave irradiation. Hydroxylamine hydrochlorides were reacted with several aliphatic and aromatic aldehydes and ketones affording the desired oximes. 

Another widely used approach is the cyclization of oximes either under acidic, as in the conversion (147 ->148) (71MI22700), or basic conditions (149- 150) (78JOC2020). Cyclopropyl ketones (151) also react with hydroxylamine hydrochloride to give dihydro-1,2-oxazines (153), probably via the protonated oxime (152). If this is so then this reaction represents a rare example of a 6-endo-tet ring closure <80AG(E)199). 

Although the xanthones contain a ketone oxygen atom, they, like the pyrones (see p. 385), do not react with hydroxylamine, or phenyl hydrazine. 

The majority of aldehydes and ketones react with hydroxylamine, forming oximes. 

Aldehydes (e.g., citral, cinnamic aldehyde, etc.) and certain ketones e.g., acetone) react with hydroxylamine hydrochloride forming oximes with the liberation of hydrochloric acid (Z. a., 1895, 623) which can be titrated in presence of methyl orange. 

In the example included here (Expt 5.100) ethyl methyl ketone is nitrosated to butane-2,3-dione monoxime, which is then reacted with hydroxylamine to give the dioxime, dimethylglyoxime, the well-known reagent for nickel. 

Dihydropyridines containing at position 3 a carbonyl group similar to oc,(3-unsaturated ketones can be involved in cyclocondensation reactions with 1,2-binucleophiles. Dihydropyridine 376 treated with hydroxylamine yields isoxazoline derivatives 377 [363, 382, 383, 384, 385, 386] (Scheme 3.122). Dihydro-l,2,4-triazolo[l,5- ]pyrimidine 378 reacts with hydrazine and hydroxylamine in the same manner, giving the condensation products 379 [387]. 

Cyclodextrin ketones have been used as powerful catalysts of amine oxidation in the presence of hydrogen peroxide as the stoichiometric oxidant. This oxidation follows Michaelis-Menten kinetics and depending on the substrate the oxidation rate is increased up to 1100-fold. It has been proposed that hydrogen peroxide reacts with the ketone to form a hydroperoxide adduct and this adduct is responsible for oxidizing the amine, bound in the cavity, to the hydroxylamine.189... 

In an aqueous medium buffered by sodium acetate, acetylenic ketones react with potassium telluride to give bisfacylvinyl] telluriums. These reactions were performed in the presence of hydroxylamine-Osulfonic acid with the goal of preparing 2-azatellurophenes. The formation of divinyl tellurium compounds competes with the formation of the heterocycles6. 

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