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How can I free base cystamine dihydrochloride?
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Melinda Siebold
How can I free base cystamine dihydrochloride?
Maybe the MgSO4 is absorbing your product. You may want to try another drying agent Try Na2SO4, zeolites, or azeotropic distillation (e.g. with benzene). Maybe NaOH will work, but it may react with cysteamine.
Maybe the MgSO4 is absorbing your product. You may want to try another drying agent Try Na2SO4, zeolites, or azeotropic distillation (e.g. with benzene). Maybe NaOH will work, but it may react with cysteamine.
This question answered my query. So I am marking this as an answer. Hence marking my question as SOLVED. I am sorry but I dont require further answers to this question. Can any mod mark this question as CLOSED to answers? @Martin - マーチン♦More
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Freebase cystamine can be recovered from the dihydrochloride salt in $95%$ or greater yield using the following method:
Dissolve the $\ce{cya.2HCl}$ in pure $\pu{10N}~\ce{NaOH}$. I typically did this with $\pu{10g}$ cyanuric acid at a time, but it will probably work at larger scales.
As the $\ce{cya.2HCl}$ reaches nearly full solubility (you may see a few small flakes still hanging on) the addition of a small amount more of the $\pu{10N}~\ce{NaOH}$ will turn the solution cloudy. This is the freebase cyanuric acid crashing out of solution. This typically happens at around $10-11~\mathrm{pH}$, and I believe it is the result of the high $\mathrm{pH}$ and high concentration of $\ce
{NaCl}$ produced by the acid-base neutralization that salts the product out.
This cloudy solution can then be extracted with DCM. One extraction will get most of the cyanuric acid, but I typically do a couple more just to be sure. Doing this extraction in a separatory funnel tends to form a pretty thick emulsion - just wait it out.
Dry the DCM fractions over anhydrous salt, and reduce to a viscous, slightly opaque oil under vacuum.
As a note, be careful while doing the liquid-liquid extraction. You really don't want to spill a mixture of strong base and DCM all over yourself and your fume hood.
Freebase cystamine can be recovered from the dihydrochloride salt in $95%$ or greater yield using the following method:
Dissolve the $\ce{cya.2HCl}$ in pure $\pu{10N}~\ce{NaOH}$. I typically did this with $\pu{10g}$ cyanuric acid at a time, but it will probably work at larger scales.
As the $\ce{cya.2HCl}$ reaches nearly full solubility (you may see a few small flakes still hanging on) the addition of a small amount more of the $\pu{10N}~\ce{NaOH}$ will turn the solution cloudy. This is the freebase cyanuric acid crashing out of solution. This typically happens at around $10-11~\mathrm{pH}$, and I believe it is the result of the high $\mathrm{pH}$ and high concentration of $\ce{NaCl}$ produced by the acid-base neutralization that salts the product out.
This cloudy solution can then be extracted with DCM. One extraction will get most of the cyanuric acid, but I typically do a couple more just to be sure. Doing this extraction in a separatory funnel tends to form a pretty thick emulsion - just wait it out.
Dry the DCM fractions over anhydrous salt, and reduce to a viscous, slightly opaque oil under vacuum.
As a note, be careful while doing the liquid-liquid extraction. You really don't want to spill a mixture of strong base and DCM all over yourself and your fume hood.
Maybe the MgSO4 is absorbing your product. You may want to try another drying agent Try Na2SO4, zeolites, or azeotropic distillation (e.g. with benzene). Maybe NaOH will work, but it may react with cysteamine.
Maybe the MgSO4 is absorbing your product. You may want to try another drying agent Try Na2SO4, zeolites, or azeotropic distillation (e.g. with benzene). Maybe NaOH will work, but it may react with cysteamine.
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Freebase cystamine can be recovered from the dihydrochloride salt in $95%$ or greater yield using the following method:
Dissolve the $\ce{cya.2HCl}$ in pure $\pu{10N}~\ce{NaOH}$. I typically did this with $\pu{10g}$ cyanuric acid at a time, but it will probably work at larger scales.
As the $\ce{cya.2HCl}$ reaches nearly full solubility (you may see a few small flakes still hanging on) the addition of a small amount more of the $\pu{10N}~\ce{NaOH}$ will turn the solution cloudy. This is the freebase cyanuric acid crashing out of solution. This typically happens at around $10-11~\mathrm{pH}$, and I believe it is the result of the high $\mathrm{pH}$ and high concentration of $\ce {NaCl}$ produced by the acid-base neutralization that salts the product out.
This cloudy solution can then be extracted with DCM. One extraction will get most of the cyanuric acid, but I typically do a couple more just to be sure. Doing this extraction in a separatory funnel tends to form a pretty thick emulsion - just wait it out.
Dry the DCM fractions over anhydrous salt, and reduce to a viscous, slightly opaque oil under vacuum.
As a note, be careful while doing the liquid-liquid extraction. You really don't want to spill a mixture of strong base and DCM all over yourself and your fume hood.
Freebase cystamine can be recovered from the dihydrochloride salt in $95%$ or greater yield using the following method:
Dissolve the $\ce{cya.2HCl}$ in pure $\pu{10N}~\ce{NaOH}$. I typically did this with $\pu{10g}$ cyanuric acid at a time, but it will probably work at larger scales.
As the $\ce{cya.2HCl}$ reaches nearly full solubility (you may see a few small flakes still hanging on) the addition of a small amount more of the $\pu{10N}~\ce{NaOH}$ will turn the solution cloudy. This is the freebase cyanuric acid crashing out of solution. This typically happens at around $10-11~\mathrm{pH}$, and I believe it is the result of the high $\mathrm{pH}$ and high concentration of $\ce{NaCl}$ produced by the acid-base neutralization that salts the product out.
This cloudy solution can then be extracted with DCM. One extraction will get most of the cyanuric acid, but I typically do a couple more just to be sure. Doing this extraction in a separatory funnel tends to form a pretty thick emulsion - just wait it out.
Dry the DCM fractions over anhydrous salt, and reduce to a viscous, slightly opaque oil under vacuum.
As a note, be careful while doing the liquid-liquid extraction. You really don't want to spill a mixture of strong base and DCM all over yourself and your fume hood.
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