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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Urbanium on March 24, 2014, 06:28:07 AM

Title: A question on protection
Post by: Urbanium on March 24, 2014, 06:28:07 AM
Hello,

I'm doing a protection of secondary amine in thiomorpholine ring, and it's the first time in general I'm doing a protection of an amino group. I've checked in papers if there is some procedure for this particular case, but I wasn't able to find it.

In your opinion, is Boc a good protective group in this case? My substrate is a secondary amine incorporated in the ring, and I'm not sure if classic Boc procedures will work here).

 Which molar ratios of substrate vs. Boc2O vs. DMAP should I use in this case (i.e. is there some rule of thumb for molar ratios when it comes to Boc protection)?
Title: Re: A question on protection
Post by: sjb on March 24, 2014, 08:45:27 AM
Hello,

I'm doing a protection of secondary amine in thiomorpholine ring, and it's the first time in general I'm doing a protection of an amino group. I've checked in papers if there is some procedure for this particular case, but I wasn't able to find it.

In your opinion, is Boc a good protective group in this case? My substrate is a secondary amine incorporated in the ring, and I'm not sure if classic Boc procedures will work here).

 Which molar ratios of substrate vs. Boc2O vs. DMAP should I use in this case (i.e. is there some rule of thumb for molar ratios when it comes to Boc protection)?

What are you hoping to protect this against?
Title: Re: A question on protection
Post by: Urbanium on March 24, 2014, 09:23:44 AM
Well I can't quite say that, only that I'm doing a nucleophile displacement on sulfur, and there is a very good chance the secondary amine in thiomorpholine would react, so I need to protect it somehow in order to restore it later.
Title: Re: A question on protection
Post by: TheUnassuming on March 24, 2014, 09:31:54 AM
A simple boc protection should work just fine. 
I typically use catalytic DMAP with around 1.25 equiv of boc anhydride.  I recently did this on a non-aromatic heterocyclic amine and it worked just fine.