Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: URgEnthalpy on August 10, 2018, 07:06:08 AM
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I can't find literally any info about solubility of aminoacids and similar compounds (creatine, taurine) in organic solvents.
I am a little bit confused if the best solubility would be in their isoelectric point, or protonated/ deprotonated form. Would be direct pouring on the powders CH2Cl2 better, or making solution in the first place and adjusting right pH is a better solution?
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I have often worked with amino acids, but I have not seen information on the solubility in in organic solvents. I suspect that you are correct about the isoelectric point. Obviously if working with them as BOC-derivatives is a possibility, that might be somewhat easier. However, my experience is that even BOC-derivatives will partition from ethyl acetate into water if the carboxylic acid group is deprotonated to form a carboxylate. Were you able to calculate the pI values of the compounds of interest to you?
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I bet they are all soluble in methanol, DMF and DMSO at all pHs.
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https://www.tandfonline.com/doi/pdf/10.1080/00021369.1966.10858601
Hayashi K, et al., Agr. Biol. Chem., Vol. 30, No.4, pp. 378-384, 1966
See Table I for data on methanol and ethanol.
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Dang, I was wrong. This data says to me that there isn't a blanket statement one can make about amino acid solubility, it's a case by case basis. At their isoelectric point they will indeed be most soluble in organics like DCM.
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One question that has long occurred to me is what is the tautomeric equilibrium for an amino acid in an organic solvent. I would think that it would be very different from water, but I have never seen data that address this question.