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Topic: Amine protecting groups  (Read 9924 times)

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Offline 408

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Amine protecting groups
« on: December 12, 2011, 09:29:39 AM »
Hi,

I have a heterocyclic amine which I need to protect towards oxidizing conditions.  Any recommended protecting groups?  It needs to survive aqueous acidic peroxide based oxidation reagents.

Thanks,
408

Offline Honclbrif

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Re: Amine protecting groups
« Reply #1 on: December 12, 2011, 10:42:28 AM »
You can probably get away with Fmoc
Individual results may vary

Offline OC pro

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Re: Amine protecting groups
« Reply #2 on: December 12, 2011, 04:00:30 PM »
If it is only slightly acidic: Boc boc boc boc boc boc...one of my favorites. ;D
Survives generally even acetic acid at room temperature.

Offline Oxime

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Re: Amine protecting groups
« Reply #3 on: December 12, 2011, 10:50:25 PM »
Cbz (Benzyloxy carbamate) protecting group is stable to even highly acidic conditions (TFA at room temp, 2-4 hours) but I'm not sure about its stability under oxidative conditions.

Offline Honclbrif

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Re: Amine protecting groups
« Reply #4 on: December 13, 2011, 12:21:31 PM »
Depending on what's being oxidized, it may all be undone when removing the Cbz.
Individual results may vary

Offline fledarmus

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Re: Amine protecting groups
« Reply #5 on: December 13, 2011, 01:59:04 PM »
Echo what Honclbrif said - you may need to select your deprotection conditions carefully. Cbz is frequently removed by reduction, which may also reduce the group you just oxidized.

Offline 408

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Re: Amine protecting groups
« Reply #6 on: December 13, 2011, 04:33:36 PM »
I will give the above a shot!  Thanks!

Offline Åke

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Re: Amine protecting groups
« Reply #7 on: December 27, 2011, 09:44:54 PM »
You can probably get away with Fmoc

Is using Fmoc really getting away with it? 408, have you considered good old acetyl? Trifluoroacetyl is another, very useful protecting group for amines, it's really easy to attach and to hydrolyze - I'd give it a shot. Next on the list would be tosyl and analogs. I'd consider fancy protecting groups only if the simpler ones would prove unsuitable. What ya reckon, bad boys?  8)

Offline 408

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Re: Amine protecting groups
« Reply #8 on: December 29, 2011, 06:42:31 AM »
I protected with pthalic anhydride ;)  cheap and easy. 
And far more stable than the others, its gotta survive hypofluorous acid ( Did I mention I love my chemistry?)

Offline Åke

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Re: Amine protecting groups
« Reply #9 on: December 29, 2011, 05:54:59 PM »
I protected with pthalic anhydride ;)  cheap and easy. 
And far more stable than the others, its gotta survive hypofluorous acid ( Did I mention I love my chemistry?)

That's interesting, I didn't suggest phtalimide earlier since I assumed that your amine wasn't a primary one - based on your earlier post:

Hi,

I have a heterocyclic amine which I need to protect towards oxidizing conditions.  Any recommended protecting groups?  It needs to survive aqueous acidic peroxide based oxidation reagents.

Thanks,
408

Now, either your "heterocyclic amine" substrate contains a mysterious primary amino group, which you happily protected with phtalic anhydride, or you made a really bad choice when selecting a protecting group for the endocyclic amino group.  ;)

Offline Honclbrif

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Re: Amine protecting groups
« Reply #10 on: December 29, 2011, 06:02:57 PM »
Also, when did we go from peroxide to hypofluorous acid?
Individual results may vary

Offline 408

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Re: Amine protecting groups
« Reply #11 on: February 17, 2012, 04:18:24 PM »


It was a heterocyclic N-NH2 group.  Sorry for confusion.

HOF stinks. Fluorine smells like clean chlorine, but this stuff smells like F2 farted in an elevator.


Offline veselin

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Re: Amine protecting groups
« Reply #12 on: January 24, 2014, 11:41:37 AM »
Is Phthalimide as protective group for amines stabile in alkylation with NaH/propargyl bromide? Thanks

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