Leading Question

LEADING QUESTION



Why Did They Use T3P?

Just why exactly did Gutekunst and his chemical pals decide to use T3P (Propylphosphonic Anhydride) as the amide coupling reagent in this specific synthesis?

To Appeal to all you visual learners out there, we have this table. For those of you that like to read books... put your mouse on it.

Yes, Euitical's marketing team did a wonderful job. From the visual and released statement above, it would just be plain silly to use any other amide coupling reagent. However, for less commercial evidence, one could look to the claims of Hiebl, "T3P® was superior to other reagents with regards to yield and low epimerisation." Though high yield, and low epimerization could be the reason T3P was chosen, we will never know.

Other amide coupling reagents they could have used, and possible reasons why they may have not used them...

 


Other Amide Coupling Reagents


 


TBTU- “ O-(Benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate“ According to the paper published by Valeur reviewing various amide coupling reagents, the relative time that it takes for a reaction with TBTU to go to completion is longer. In addition to the longer reaction time, it has a (relatively) lower yield. Though we wont know what was going throught the researchers heads when they ruled out using TBTU as the amide coupling agent, but the aforementioned resons could have factored in to thier decision.


 


BOP – Also called Castro’s reagent, BOP is discouraged for laboratory use because it liberates large amounts of HMPA which is a known carcinogen. On the basis that cancer is a horrendous disease, it is possible that BOP was not chosen as the amide coupling reagent because fo the large amount of dangerous by-products created.


 


DCC - N,N'-dicyclohexylcarbodimide is an amide coupling reagent used primarily for solid phase peptide synthesis. DCC was most likely not used in the synthesis of 20 due to the fact that our peptide synthesis was in liquid, not solid.


 

 


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