After BOC depreciation by TFA and DCM I probably got R-NH3+-OOCCF3 after evaporation. But I want to get the compound salt free (R-NH2 form) ? How can I get R-NH2 form from R-NH3+-OOCCF3 ?
NaHCO3 is not strong enough base to deprotonate an ammonium.
- If your amine is soluble in organic solvents (like EtOAc or DCM) : Extract your compound in the presence of a strong base like NaOH (your aqueous phase should be at least pH 12).
- If your amine is not soluble in organic solvents then dissolve it in water or methanol and use a basic resin like IRA-67 resin, check the pH, filter and evaporate... very easy!
(http://www.sigmaaldrich.com/catalog/product/aldrich/476633?lang=fr®ion=FR)
Hope it will help!
Dear Muhammad:
You need to pass ammonia gas through your resulting mixture. See synthesis of amines.
R-NH3+-OOCCF3 +NH3 = R-NH2 +NH4+-OOCCF3
Best regards.
intensive shaking of your salt solution with the mixture of 1M sodium bicarb removes acid counter-ions as well. Dissolve your compound in organic solvent, add to separatory funnel. Add aq. solution of bicarb and shake well. This method works well both for prior-to-use simple amino acid precursors and for the final compound. Although, for prolonged storage it is recommended to keep the salted form and make it acid-free just right before use. Also keep in mind that in case if you have open C-end, you'll get Na-salt of your compound. then Yuri's advise will be the best choice.
NaHCO3 is not strong enough base to deprotonate an ammonium.
- If your amine is soluble in organic solvents (like EtOAc or DCM) : Extract your compound in the presence of a strong base like NaOH (your aqueous phase should be at least pH 12).
- If your amine is not soluble in organic solvents then dissolve it in water or methanol and use a basic resin like IRA-67 resin, check the pH, filter and evaporate... very easy!
(http://www.sigmaaldrich.com/catalog/product/aldrich/476633?lang=fr®ion=FR)
Hope it will help!
Thank you very much Mr. Mayeul Collot,
My compound is soluble in both water and methanol, IRA-67 resin is not available in my store. I use thriethylamine in methanol and stirred for three hours then filtrated and evaporated. But still it seems , it is not free R-NH2 form. Is there any alternative suggestions ??
Review this;
http://www.waters.com/waters/library.htm?cid=511436&lid=10122759&xcid=ext5325&utm_content=sf54187503&utm_medium=spredfast&utm_source=linkedin&utm_campaign=Waters+Corporation&xcid=sfwaters-linkedin-b-CBU+p-CBU+Columns+Field+Marketing+promo-sf54187503&sf54187503=1&locale=101
review this,
https://www.biosciencetechnology.com/article/2015/11/exchanging-out-tfa-synthetic-peptide-preparations-why-its-important-and-how-do-it-effectively
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