QDIS Blog

In getting caught up on some of my literature reading, I came across an interesting article from the journal Organic Process Research and Development. Having spent my career as a development chemist, this journal is invaluable in keeping up to date with tricks and tips for large scale production. The following article was in the latest issue (Organic Process Research & Development 2006, 10, 163−164).

A Simple Modification to Prevent Side Reactions in Swern-Type Oxidations Using Py·SO3 Lijian Chen,* Steven Lee, Matt Renner, Qingping Tian, and Naresh Nayyar Chemical Research and Development, La Jolla Laboratories, Pfizer Inc.

The article describes using excess pyridine to convert the pyridine•sulfuric acid 1:1 salt which is present in commercial pyridine•sulfur trioxide to a 2:1 salt. This prevents unwanted side reactions from occurring, at least in this report. In this case they are oxidizing a primary alcohol to an aldehyde and then performing a Wittig reaction without isolating the aldehyde (a common approach in chemical development and production).

I just find it interesting that as widely used as the Swern oxidation is, this hasn’t been reported before. It is interesting to know that there are still “well-known reactions”, that actually aren’t. My usually reaction to being presented with a route containing a Swern oxidation is to ask what other oxidizing conditions have been tried. Unfortunately, at least early in the development process, nothing else was tried because the Swern oxidation worked so well.

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