Hydroxylamine-<7-sulfonic acid secondary amines

Organoboranes react with a mixture of aqueous NH3 and NaOCl to produce primary amines. It is likely that the actual reagent is chloramine NH2CI. Chloramine itself,hydroxylamine-O-sulfonic acid in diglyme, and trimethyl-silyl azide " also give the reaction. Since the boranes can be prepared by the hydroboration of alkenes (15-16), this is an indirect method for the addition of NH3 to a double bond with anti-Markovnikov orientation. Secondary amines can be prepared by the treatment of alkyl- or aryldichloroboranes or dialkylchlorobor-anes with alkyl or aryl azides. 

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

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." ... 

Primary, secondary, and tertiary amines can be aminated by chloramine also, but pyridine nitrogens have been aminated only by hydroxylamine-O-sulfonic acid. 

Hydroxylamine-O-sulfonic acid (aminyl hydrogen sulfate) has often proved superior to chloramine for amination the former is a stable crystalline substance that can be easily handled and weighed. It aminates primary279,280 and secondary amines280 to hydrazines, and tertiary amines to hydrazinium salts.28<> It is a stronger animating agent than chloramine as it converts pyridine into the 1-aminopyridinium salt, a reaction that cannot be carried out by chloramine.281 Other heterocycles, e.g., uracil,282 can also be converted into hydrazines by hydroxylamine-O-sulfonic acid. 

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