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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: asa029 on May 29, 2011, 04:55:40 AM

Title: N-detosylation of heterocycle
Post by: asa029 on May 29, 2011, 04:55:40 AM

I need to N-detosylate a heterocyclic compound. I've seen different procedures in the litterature, but the yield is usually pretty low and the reaction conditions are pretty harsh. Such procedures include using lithium or sodium metal in methanol, different kinds of amalgams or very strong basic conditions. I've also seen an article describing using a two-phasic system and a PTC. Does anyone have any experience or thoughts on the subject?

Title: Re: N-detosylation of heterocycle
Post by: rucik5 on May 29, 2011, 06:18:39 AM

There was a paper (in Org Lett I think) released quite recently about a detosylation procedure with samarium iodide, base (triethylamine or pyrrolidone) and water. They managed to remove the tosyl from an Ts-N-Boc cmpnd, leaving the Boc intact.

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fimg821.imageshack.us%2Fimg821%2F5074%2F600pxsmi2detosylation.png&hash=f6c22a59c25f5f25755e1962938cb36bd6de45cd)

Here: http://pubs.acs.org/doi/abs/10.1021/ol802243d

They use 6 equivalents of it, but the whole reaction is complete in seconds, and 100ml 0.1M sln of SmI2 in THF is available from sigma. Yield are in 80-90% i believe.

Title: Re: N-detosylation of heterocycle
Post by: nox on May 29, 2011, 10:14:52 PM

Is there anything Samarium iodide won't do?