I have a peptide of 31 amino acid chain length, consisting of amino acids like histidine, arginine, tryptophan. I have to remove the t-butyl group from the alpha carboxyl of glutamic acid. I am looking for the suggestions regarding the scavenger combinations required in this TFA mediated cleavage step.
Hello! I typically use TFA/Water/TIPSI/PhOH mixture (8.8/0.5/0.2/0.5 vol). For sequences involving f.eg. Arg I often have to repeat the cleavage or extend the time as the Pbf group isn't always removed. Hope that helps.
Dear All, Thank you very much for your valuable suggestions!
@Ali Abdil Razzaq Muhammed Noori Aldallal . Sir, your notes do gave me useful insight.. As I am also new in Peptide chemistry..
@Sławomir Lach , I don't have any additional protecting groups..t-Butyl is the final protecting group on -COOH of glutamic acid. So I hope this method works well..
@ Sergio Celis.. Thanks a lot.. I till try triethyl silane...
hi pratap
I use TFA/Water/TIPSI/PhOH mixture (8.8/0.5/0.2/0.5 vol). For sequences involving f.eg. Arg I often have to repeat the cleavage or extend the time as the Pbf group isn't always removed. hope i would help you.. all the best
Thanks a lot Satya.. My initial concern was the report where reduction of Tryptophan ring was mentioned when triethylsilane was used. However, based on the suggestions here, I will check this combination. As I don't have any other protecting groups, I hope the reaction will be smooth and no need to repeat.
Thanks a lot again..
If you fear the t-Bu will be transferred to any thiols in your product, add ethylene dithiol.
Dear Ruben Leenders,
Thiol specially EDT in combination with thioanisol and phenol is the best option (from my search). However, in industry not many people prefer to use thiol....So I am keeping this as a last option..
Hi,
To confirm what has been said, I also use a solution of TFA/H2O/TIS (95/2.5/2.5),
and sometimes more than 4h are needed to deprotect groups like Pbf from Arg.
Good luck.
A solution of TFA/H2O/TIS (95/2.5/2.5) is a perfect method to handle t-Butyl group and work well with all peptide and small molecules..
Good Luck
Hi Pratap Subhashrao Patil, you can use TCEP (tris(2-carboxyethyl)phosphine) as an alternative to EDT.
- Badges
- Science topic
- Similar topics
- Force