Friday, May 16, 2008

Reactions that work from chemistry notes

Looking for a way to prepare nucleoside-5'-carboxylic acids? Then I have just the reaction for you. Using a procedure adapted from Epp and Widlanski [1], one can easily make these carboxylic acids in just under three hours. In my hands, this reaction has worked wonderfully every single time, producing relatively pure product without much effort on my part; over the years it has become one of my favorite reactions.


Here is a sample procedure, exactly as it appears in my lab notebook:

Place 5g of acetonide protected adenosine in a 100ml round bottom flask. Add stir bar, 11.53g of DIB and 0.51g of TEMPO. Add 15ml of acetonitrile to 15ml of water and add to the reaction flask. Stir. After about 15 minutes the the reaction will turns a deep brown-orange color and the components begin to dissolve. Shortly after this a white precipitate forms. Stir for an additional 3 hours. Filter the solid and triturate sequentially with acetone and diethyl ether (3x each, 15ml). Dry the resulting solid under vacuum. No further purification necessary.

Yield: 4.98g, 96.8%

Large or small scale, the yield for this reaction is usually in the 90% range.

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