I synthesised [3,5 -bis(tolyl carbamoyl)phenyl pivalate] by reaction of 5-acetoxyisophthalic acid with p-aminotoluene and i used DMAP and DIC as a catalyst.
Hi,
Assuming column chromatography hasn't worked, maybe you could selectively hydrolyse the pivalate ester to the phenol, extract it into aqueous base, isolate the phenol, then re-acylate it with pivaloyl chloride (assuming the amides don't react)
Bill
1) Your product might really show a high tendency to crystallization, perhaps EtOAc heptane or MTBE might be useful here; if not immediately successful
2) Dissolve the crude product in 2-Me-THF or in CH2 Cl2, wash the solution with 0.5 N HCl (that removes DMAP); separate the phases, wash the organic phase with water, separate the phases well, concentrate the organic phase to dryness
3) Try recrystallizing the product-again I expect it to be highly crystalline.
Indeed, don't bother with chromatography; it should be easy to recrystallize. Or perhaps simple precipitation is sufficient? Did you wash with acid? did you get a solid or an oily material after removal of the solvent?
I recommend water with some trepidation, as i find it hard to gauge the stability of the pivalate ester. Often, these electron poor phenolates are somewhat reactive.
Yes , i used dilute hydrochloric acid and i extracted it but it was pointless !
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