peppovsky
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Primary amine from secondary alcohol?
I know that one can take a secondary alcohol, and substitute the OH group with Tosyl Chloride, Mesyl chloride, etc. - and then react it with a primary
amine to form a secondary amine-substituted compound, and TsOH (or other leaving groups depending of the one chosen from above).
Can one do the same thing with (I guess anhydrous) ammonia, to gain a primary amine?
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DJF90
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It would be easier to oxidise your alcohol to the ketone, and then perform a reductive amination. Assuming you have the reagents that is.
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peppovsky
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perhaps, but I ask about this specific reaction (I don't like messing around with Jones reagent, its dirty and toxic as hell).
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DJF90
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Jones reagent isn't the only way to oxidise a secondary alcohol. Theres a whole plethora of methodologies applicable to a wide range of substrates - I
suggest you look into this. As for the specific reaction, it would likely depend on the substrate and the conditions. If you're hell bent on going via
the tosylate, consider using a "single ammonia equivalent", such as K-Phthalimide (Gabriel synthesis) or azide, followed by an appropriate work up
(KOH/hydrazine or Ph3P respectively) to furnish the desired primary amine.
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peppovsky
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The problem with the Gabriel synthesis is that it requires a primary halide, and doesn't work with secondary halides. Maybe a tosylate ether and
potassium phthalimide react to create an amine, but I'm not familiar with this reaction. Any references?..
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Nicodem
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Quote: Originally posted by peppovsky  | | perhaps, but I ask about this specific reaction (I don't like messing around with Jones reagent, its dirty and toxic as hell). |
You describe no specific reaction so you can't seriously expect a specific answer. It is simply not possible to predict the outcome of a reaction of a
nonspecific sec-alkyl tosylate with ammonia (whether in solution or liquid). Without knowing the steric and electronic properties of R and R'
your question can not be answered, because it is impossible to tell which of the possible reactions (E2, SN2 with mono or dialkylation, or no
reaction) will be prevalent.
The only useful answer you can currently get, based on the useless information you gave, is to forget about ammonia or phthalimide. Only nucleophilic
substitution with NaN3 followed by reduction has a scope wide enough to cover most cases of R and R'.
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