[CPC]

Hallo,
i am doing a synthesis of an oxime from tert-butyl acetoacetate using NaNO2 in acetic acid (see the reaction scheme attached). I follow the procedure described in Tetrahedron Asymmetry, 1991, 2, 555. It was reported that from tert-butyl acetoacetate, a white solid product with m.p. of 68 ^OC was obtained in high yield.
I have obtained an colorless oil. I suppose that it is still a mixture of the product (oxime), tert-butyl acetoacetate and probably acetic acid.
I will try to improve the operation to get the compound in high yield so that i do not have to care much about purification. However, I am thinking a way to separate the oxime from the mixture I have got today-the result of my first experiment concerning the topic. I still do not have a sound idea, how to do it. I do not think that recrystalization may help because it seems that the mixture contains considerable amounts of the starting materials. Column chromatography may help but I could not do TLC to look for a proper solvent system since the compounds may be invisible under UV light.
I appreciate any of your suggestions.
Thank you.
CPC

[kryptoniitti]

Column chromatography may help but I could not do TLC to look for a proper solvent system since the compounds may be invisible under UV light.
I appreciate any of your suggestions.
Thank you.
CPC

You might still be able to use TLC eventhough the compounds are invisible under UV; there are different colouring solutions for TLC that you dip the plate in and then heat it with hot air blower or put it in an oven for  awhile. Any handbook of practical organic chemistry or TLC should give you detailed information about this procedure.

[phil81]

TLC stains: http://chem.chem.rochester.edu/~nvd/tlcnotes.html (a very useful website anyway)

Crystallization sounds like a good idea to me. The product is described as a solid, and both your contaminants are liquid and probably much more water-soluble. I would try crystallization from water or an aqueous solvent mixture.

[CPC]

Hallo,
thank you for your suggestions.
The idea of using some solutions to help visualize the components seems interesting and the link to Stains for Developing TLC Plates are very helpful.
If it possible one may try a TLC and do a column.
Concerning recrystalization, I am quite afraid that the mixture still contains a large amount of tert-butyl acetoacetate and I am not quite sure whether it is quite soluble in water. I would do try anyway.
Best regards,
CPC