Hydroxylamine 0-sulfonic acid, synthesis

Other Applications. Hydroxylamine-O-sulfonic acid [2950-43-8] h.2is many applications in the area of organic synthesis. The use of this material for organic transformations has been thoroughly reviewed (125,126). The preparation of the acid involves the reaction of hydroxjlamine [5470-11-1] with oleum in the presence of ammonium sulfate [7783-20-2] (127). The acid has found appHcation in the preparation of hydra2ines from amines, aUphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. It is also an important reagent in reductive deamination and specialty nitrile production. 

Two substituents on two N atoms increase the number of diaziridine structures as compared with oxaziridines, while some limitations as to the nature of substituents on N and C decrease it. Favored starting materials are formaldehyde, aliphatic aldehydes and ketones, together with ammonia and simple aliphatic amines. Aromatic amines do not react. Suitable aminating agents are chloramine, N-chloroalkylamines, hydroxylamine-O-sulfonic acid and their simple alkyl derivatives, but also oxaziridines unsubstituted at nitrogen. Combination of a carbonyl compound, an amine and an aminating agent leads to the standard procedures of diaziridine synthesis. 

The major development in the Knorr pyrrole synthesis has been access to the amine component. For example, use of preformed diethyl aminomalonate with 1,3-diketones affords much higher yields of pyrroles 14. Reaction of 6-dicarbonyl compounds with hydroxylamine 0-sulfonic acid gives pyrroles 15 in one step. Weinreb a-aminoamides have found use in the Knorr pyrrole synthesis of a wide variety of pyrroles 16. °... 

Thus the structure of the oxazirane must formally involve elimination of water from one molecule each of the carbonyl compound and of an alkyl hydroxylamine. (In the synthesis of oxazirane from N-methylhydroxylamine-O-sulfonic acid and benzaldehyde, this method... 

A simple chemical proof of structure of the diaziridines is given by the synthesis of the same diaziridine 42 from cyclohexanone either using methylamine and hydroxylamine-O-sulfonic acid or using ammonia and methylhydroxylamine-O-sulfonic acid. ... 

In 1979, Olah [47] reported a one step conversion of alicyclic ketones into lactams by means of hydroxylamine O-sulfonic acid and formic acid under reflux for a few hours. More recently this reaction has been realized under solvent-free conditions with Si02 as inorganic support and focused irradiation, as exemplified in Scheme 8.29 for caprolactam synthesis. 

In another variation of a type E synthesis, thioamides or thioureas condense with /V,/V-dimcthylacylamide dimethyl acetal to give imino compounds which react with amino-transfer reagents like hydroxylamine-O-sulfonic acid and mesitylsulfonyloxyamine (MSH) to give 3,5-substituted-l,2,4-thiadiazoles in excellent yields <1996CHEC-II(4)307>. There have been no new reports of type E syntheses since the publication of CHEC-II(1996). 

Sulfonylhydroxylamines and hydroxylamine O-sulfonic acid have found wide apph-cation in synthesis of amines from achiral or chiral organoboranes and boronate esters and the hydroboration-amination methodology is successfully used for direct amination of alkenes. 0-Sulfonyloximes were also found to be good reagents for synthesis of amines from organomagnesium, -copper and -zinc reagents. 

Following the demonstration of catalytic hydroboration-amination employing hydroxylamine-O-sulfonic acid as the electrophile, extension to the synthesis of secondary amines was considered. 

Hydroxylamine-G-sulfonic acid in the synthesis of heterocycles 90 WCH243. 

It is well-known that organoboranes can be utilized to yield primary amines by treating them with chloramine or hydroxylamine-O-sulfonic acid Recently Kabalka et al. reported a convenient synthesis of primary alkyl amines via the reaction of organoboranes with ammonium hydroxide in the presence of sodium hypochlorite (Eq. 13) The reaction presumably proceeds through the in situ formation of chloramine. 

The Schmitz reaction can be unsuccessful in sterically demanding environments in such circumstances, the electrophilic aminating agent reacts faster with ammonia than with hindered ketones <1965JA2665>. Consequently, the synthesis of 2-azi-camphane 64, a compound which is unobtainable under standard conditions <1996TL6647>, was achieved by slow diaziridination of camphor imine hydrochloride 63 (rather than camphor itself) with hydroxylamine-O-sulfonic acid (HOSA)-ammonia, followed by iodine-mediated oxidation (Scheme 22) <2001S379>. 

Knorrpyrrole synthesis. The reagent reacts with some active methylene compiounds to give products of C-amination. Thus 2,4-dimethyl-3,5-dicarhethoxypyrrole (2) can be prepared in one step by the reaction of hydroxylamine-O-sulfonic acid with ethyl acetoacctate (1). ... 

H(55)1759>. N-Unsubstituted l,2-benzisothiazolin-3-ones 344 (R = H R = H, Cl, OMe R = H, Cl, OMe) can be prepared in a chlorine-free synthesis by cyclization of 2-sulfenamoylbenzoates 342 (R = OR, R = NH2) which are prepared by amination of thiosalicylates with hydroxylamine-O-sulfonic acid. N-Substituted sulfenamoylbenzoates, prepared by transamination with different amines, can be cyclized to N-substituted 1,2-benzisothiazolin-3-one 344 (R = PhCH2,/ -MeOC6H4CH2,/>-ClC6H4CH2) <2003H(60)1855>. 

Electrophilic N-aminations have been performed with hydroxylamine-O-sulfonic acid (HOSA)," O-(2,4-dinitrophenyl)hydroxylamine and C>-mesitylenesulfonylhydroxylamine. The use of HOSA is mainly restricted to aqueous reaction media. Imide sodium salts of some heterocycles such as theobromine (88) can be converted to hydrazine derivatives by treatment with 0-(diphenylphosphinyl)hydroxylamine (equation 35)." This reaction has been extended to synthesis of N-arylhyd ines, where R and R are hydrogen, alkyl or aryl (equation 36)." Similarly, trisubstituted hydrazines can be prepared by the use of N-aryl-O-acetylhy oxylamines and secondary amines." A recent publication" concerning the synthesis of l-acyl-2-dkylhydrazines from hydroxamic acids and amines in the presence of activating agents has been found to be erroneous no N—N bond formation occurs under these conditions." ... 

Tamura, Y., Kato, S., Ikeda, M. One-Step Knorr pyrrole synthesis with hydroxylamine 0-sulfonic acid. Chem. Ind. 1971,767. 

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