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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: JimCronshaw on September 21, 2012, 01:18:24 AM

Title: Sulfonamide interfering with Suzuki reaction?
Post by: JimCronshaw on September 21, 2012, 01:18:24 AM

Greetings all. I'm trying Suzuki couplings and the common factor to all is the presence of a sulfonamide. I'm not getting the desired products from the reactions. Any chance that a sulfonamide might interfere? There's more detail available here

http://www.thesynapticleap.org/node/419

My lab book is open to the public, so for an example of this reaction in detail, see:

http://malaria.ourexperiment.org/aminotpseries/4436/Synthesis_of_34aminothieno32dpyrimidin6ylbenzenesulfonamide_JRC_421.html

Any ideas at all would be appreciated. I'm trying a different catalyst now (which I used successfully to make the boronic ester), to see if that makes a difference.

Thanks,
Jim.

ps: if you help, and want to be given credit for your ideas in my honours thesis (and presumably in any paper published thereafter (i should probably check with those higher up that this is indeed the case)), just message me with your name and i'll include you.

Title: Re: Sulfonamide interfering with Suzuki reaction?
Post by: OC pro on September 21, 2012, 03:03:27 AM

I see a problem with a side-reaction of the Sulfonamide with the bromo-thiophene via a Buchwald-Hartwig coupling.

Title: Re: Sulfonamide interfering with Suzuki reaction?
Post by: zoork34 on September 21, 2012, 09:02:28 AM

Along the lines of what OC pro said, but I see a potential problem with the amino group on your pyrimidine ring coupling to the aryl bromide in a buchwald-hartwig type coupling.  Those typically use stronger bases to activate the Pd-NR2 complex, but it seems possible.