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Removal of tetrabutylammonium from an organic reaction
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Marlene Dixon
Removal of tetrabutylammonium from an organic reaction
I know it is a relative old issue but I had the same problem with nucleosides during my PhD. I tried a wide range of reagents but all of them lead to the decomposition of compounds or no reaction occurred. The only one that worked was TBAF 1 M in THF. I could not extract them because they are too polar. FCC did not work at all.
Solution (at least it worked for me): after FCC, I dissolved my product with TBAF in water and pass it through a Supelco SPE DSC-C8 3 mL, 500 mg for up to 10 mg of my compound. Use only water and do it slowly. I always get the desired compound from tube one to 6-7 and no TBAF is present. It is useful if you can use a LC-MS to analyze each tube. I tried other brands and no one worked except this one. I don't work for them, just want to share my solution.
I know it is a relative old issue but I had the same problem with nucleosides during my PhD. I tried a wide range of reagents but all of them lead to the decomposition of compounds or no reaction occurred. The only one that worked was TBAF 1 M in THF. I could not extract them because they are too polar. FCC did not work at all.
Solution (at least it worked for me): after FCC, I dissolved my product with TBAF in water and pass it through a Supelco SPE DSC-C8 3 mL, 500 mg for up to 10 mg of my compound. Use only water and do it slowly. I always get the desired compound from tube one to 6-7 and no TBAF is present. It is useful if you can use a LC-MS to analyze each tube. I tried other brands and no one worked except this one. I don't work for them, just want to share my solution.
I have the same problem in my Ph.D. research. Whenever I am too lazy to skip the aqueous workup and throw the solid residue from rotavapor directly into a column for chromatography, TBA just penetrate through flash column and exist in every tube I collect. To me, aqueous workup help a lot to remove TBAF if your product is not too soluble or unstable in water. Also, TBAF is mostly used as the floride anion source because its solubility in organic solvent. Other fluoride anion source like KF can be used as alternative to TBAF with proper solvent.
I have the same problem in my Ph.D. research. Whenever I am too lazy to skip the aqueous workup and throw the solid residue from rotavapor directly into a column for chromatography, TBA just penetrate through flash column and exist in every tube I collect. To me, aqueous workup help a lot to remove TBAF if your product is not too soluble or unstable in water. Also, TBAF is mostly used as the floride anion source because its solubility in organic solvent. Other fluoride anion source like KF can be used as alternative to TBAF with proper solvent.
You may just try other fluoride salts. CsF or KF or NH4F may do the deprotection job as well as TBAF while they will not mess up in your column. I remember KF will work in acetonitrile. HF is acidic and may decompose your compound. HF-Pyridine is almost equally messy in column as TBAF a lot of time.More
I know it is a relative old issue but I had the same problem with nucleosides during my PhD. I tried a wide range of reagents but all of them lead to the decomposition of compounds or no reaction occurred. The only one that worked was TBAF 1 M in THF. I could not extract them because they are too polar. FCC did not work at all.
Solution (at least it worked for me): after FCC, I dissolved my product with TBAF in water and pass it through a Supelco SPE DSC-C8 3 mL, 500 mg for up to 10 mg of my compound. Use only water and do it slowly. I always get the desired compound from tube one to 6-7 and no TBAF is present. It is useful if you can use a LC-MS to analyze each tube. I tried other brands and no one worked except this one. I don't work for them, just want to share my solution.
I know it is a relative old issue but I had the same problem with nucleosides during my PhD. I tried a wide range of reagents but all of them lead to the decomposition of compounds or no reaction occurred. The only one that worked was TBAF 1 M in THF. I could not extract them because they are too polar. FCC did not work at all.
Solution (at least it worked for me): after FCC, I dissolved my product with TBAF in water and pass it through a Supelco SPE DSC-C8 3 mL, 500 mg for up to 10 mg of my compound. Use only water and do it slowly. I always get the desired compound from tube one to 6-7 and no TBAF is present. It is useful if you can use a LC-MS to analyze each tube. I tried other brands and no one worked except this one. I don't work for them, just want to share my solution.
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I have the same problem in my Ph.D. research. Whenever I am too lazy to skip the aqueous workup and throw the solid residue from rotavapor directly into a column for chromatography, TBA just penetrate through flash column and exist in every tube I collect. To me, aqueous workup help a lot to remove TBAF if your product is not too soluble or unstable in water. Also, TBAF is mostly used as the floride anion source because its solubility in organic solvent. Other fluoride anion source like KF can be used as alternative to TBAF with proper solvent.
I have the same problem in my Ph.D. research. Whenever I am too lazy to skip the aqueous workup and throw the solid residue from rotavapor directly into a column for chromatography, TBA just penetrate through flash column and exist in every tube I collect. To me, aqueous workup help a lot to remove TBAF if your product is not too soluble or unstable in water. Also, TBAF is mostly used as the floride anion source because its solubility in organic solvent. Other fluoride anion source like KF can be used as alternative to TBAF with proper solvent.
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