[elr41]

hey everyone,
i'm new to this forum and am in my MChem year at uni. I have been trying to make an iminium salt catalyst for asymetric epoxidation. I started with thiomicamine which i carried out reactions to protect the hydroxyl groups as an acetal and the amine protected using methyl formate. the last step was oxidation using mcpba to the sulfone. TLC showed mcpba still present plus two other spots. I carried out flash chromatography( using EtOAc as mobile phase as i was advised to do), did an HNMR on what i expected to be the product. It looks like i do have some of the amide/sulfone but its no where near a clean spectrum. I asked advice and was asked if i'd added triethylamine.. apparently forgot to tell me that bit!! Looking at the NMR there might be a possibility there's been some kind silica interaction..
so here's my question
do i combine all fractions and re-column with TEA and if so should i re-pack the column with new silica or re-use what i already have in there?
any advice would be SOO welcome!! : ) thank you all!!
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[Doc Oc]

Did you really just run a column with pure EtOAc or was it a hexane/EtOAc mixture?  If it was pure EtOAc then I can say with 99% certainty that's the issue.  Did you run a TLC of your crude mixture first?  That will tell you a lot about how your compound and the impurities will run on a column.  I don't like running columns with Et₃N and it's not necessary for your compound in my opinion, it looks greasy enough that it should slide off without needing to neutralize the silica.  Again, a TLC will give you more definitive information.

[collin_det]

Clean EtOAc can be used to "empty" the column when done, so there is no leftovers. So if you have run the column using pure EtOAc you will probably have a mixture of all you compounds.