Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: affa on April 28, 2008, 08:53:38 AM
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I am working to cleave the N-bound tert-butyl group from a tertiary amide (aliphatic one) to regenerate a N-H in secondary amide.
I have tried using trifluoroacetic acid (TFA) or even trifluoromethanesulfonic acid (TfOH) under refluxing dichloromethane conditions (~ 39 oC). However, the tert-butyl group is unreactive at all.
Can anyone suggest alternative conditions to deprotect a tert-butyl from amides? Thank for your attention.
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Can I ask why is it on there?
R.
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tert-butyl tertiary amide was prepared to control the amide rotamer by forcing another alkyl substituent (reaction site) "anti-" to the amide carbonyl. Otherwise, the alkyl substituent would be "syn-" to the amide carbonyl, which cannot lead to desired reactions.
Do you have any idea to cleave this bulky group?
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Can you expose your compound to aqueous acidic conditions?
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coz I think protic acid in non-aqueous medium is more "acidic" than that in aqueous, where the acid protons mostly occupied by aqueous but not to protonate the amide substrates.