I have performed a demethylation reaction using BBr3 and neutralized it with sodium bicarbonate solution and removed the water by lyophilization. Now, I want to separate my product from reaction mixture. My product is soluble in methanol and water. Could anybody help me to give idea for separation of the product?
Try to extract product with hot isopropanol - it will not dissolve byproducts (sodium bromide, borate and bicarbonate).
Do you have a nitrogen in your molecule, if yes, then you have the salt form which is good water soluble. If you treated your molecule with NaHCO3, then you may have compound soluble in organic solvent. NOW if you do not have N, the best way is to derivative your compound by eg. acetylate the OH group and deacetylate latter on using ion exchange.
Extract the lyophilized product with absolute methanol such that boric acid and sodium bicarbonate will not go in solution.
Have any of the suggested answers worked for you? If not, I have more but I see no need in providing more comment if the answer is already known.
Dear Solimabi Wahidullah,
I do not wish to contradict you but, rather, alert you to a fact of boric acid.
It is more soluble in methanol than in water.
Dear Girdhar Singh Deora,
Boric acid can be removed from a sample by repeated evaporation in the presence of methanol. "Boric acid...is subsequently removed by methanol dry-down: sufficient 100% methanol is added to the sample to resuspend it, mixed and evaporated using a vacuum centrifuge set at medium heast (about 60C). - M. Fukoda in "Functional Glycomics"
Or see: Gigg, et al., STRUCTURE OF PHYTOGLYCOLIPID - Biochemistry of the Sphingolipids: XVI. J. Biol. Chem. 1964, 239:743-746.
Or see: Raja, RH et al., Analytical Biochem. 139:168 (1984).
Thanks Joe and Jawad and all researcher. I'll try to follow your valuable suggestions. Thanks again.
Giri
I know that this discussion was 5 years ago, but I need help. I performed demethylation (using BBr3) of a compound, and at the end of the reaction the product had three phenols and one primary amine (in the bromide salt form). At the end of the reaction a solid formed (insoluble in dichloromethane), which I filtered and dissolved in water to destroy the complex formed between phenol and BBr2. Since my compound is soluble in water (and methanol) i did a dialysis and liophilization afterwards. Since the resulting solid was not pure I dissolved in IPA and after filtration I obtained my compound in the filtration. This procedure worked very well for a 100-300 mg reaction. When i did a 2g reaction i could not obtaind the same results with IPA. After liophilization what do you recommend?
- Badges
- Science topic
- Similar topics
- Chemistry