Benzohydroximinoyl chlorides are useful precursors to nitrile oxides used in the preparation of various heterocycles via 1,3-dipolar cycloadditions. These intermediates are typically accessed by oxidation of aldoximes using N-chlorosuccinimide. The simple and efficient reaction is highly exothermic and an induction period can be observed. The potential for a sudden and significant heat release makes large scale reactions difficult to control and potentially hazardous.
This presentation describes a thermal analysis of this reaction to determine the heat flow in the presence of common additives to determine the most effective means of safe scale-up. Of the additives screened, aqueous HCl consistently avoided an induction period and enabled a dose-controlled process to be developed.
Guest Presenter – Eric Hansen, Pfizer
Eric received his undergraduate degree in chemistry from Calvin College and PhD from the University of Wisconsin-Madison. In 2006, he joined the process chemistry group at Wyeth before transferring to the Research-API group at Pfizer in 2010.
This was originally presented at the 17th International Process Development Conference in Baltimore, MD.