[antracene]

hi everybody

i'm looking for a way to concentrate a complex natural product that was given to me in a solution of DMA.

there is only about 1-2mgs of it and i need to dissolve it in water.  all DMA must be removed as it is detrimental to my protein studies.  i'm a little nervous about extracting it because i don't want to lose any material, as it's the last i'll ever receive.  the compound is clean by HPLC, so all i really need to do is remove the DMA.

are there any cosolvents one can add to help with the lyophilization?  i was told DMSO:dioxane works great; does this work with DMA as well? 

is there something else that i can do to remove the DMA?

any suggestions would be appreciated.

[Babcock_Hall]

I am unfamiliar with the abbreviation DMA.  What does it mean?

[nox]

dimethylacetamide perhaps?

[OC pro]

DMA will not be removed by lyophyllization. Only water and 1,4-dioxane can be removed this way.

[milo2112]

A Lyophilizer will remove the dma, but probably not through sublimation. Take your stuff in a large roundbottom and put it on a good vacuum line and let it go for a while. Once the majority of the DMA is gone, add some water and lyophilize it. 

[OC pro]

A Lyophilizer will remove the dma, but probably not through sublimation. Take your stuff in a large roundbottom and put it on a good vacuum line and let it go for a while. Once the majority of the DMA is gone, add some water and lyophilize it. 

Nope. Like DMSO, DMA is very difficult to remove on the vacline.

[milo2112]

I dislike being difficult, but I do this quite often. I find 0.25 mmHg and 50-60C tends to do the trick. Of course, my vac gauge could be off, so the vacuum could be lower.

[curiouscat]

A Lyophilizer will remove the dma, but probably not through sublimation. Take your stuff in a large roundbottom and put it on a good vacuum line and let it go for a while. Once the majority of the DMA is gone, add some water and lyophilize it.

Why are DMSO / DMA hard to remove? Presumably because of a low Vap. Pr. / High BP?

If so, how does lyophilization help? Just wondering about the rationale. Is it because they have relatively high M.P.'s?