Weaker bonds

Over the past two weeks I attended the Pacifichem meeting (http://www.pacifichem.org) in Honolulu and took a vacation with my wife. Several days ago I could not sleep because of the howling wind from the Pacific. Last night here in Oakville, it was a thunderous thump of a different kind – that of freezing rain – that kept me awake. Strangely, I have no longing for the tropical paradise my wife misses so much now. I feel in place in the midst of our barren winter landscapes, most likely because it is the climate I grew up in (granted, several thousand miles to the East of here).

Pacifichem was great, as it usually is. In the next few days, I will share some notable vignettes.

Due to my lab’s general interest in weak amide bonds, I have been trying to read about the imide functionality. The vast majority of known methods involve strong base-mediated acylation of NH amides. While attending the peptide section at the Pacifichem, I was intrigued by the presentation of Craig Hutton, who described his lab’s interests in building peptides. While Craig makes imides with the ultimate goal of hydrolyzing them post-coupling, my lab has been keen to study imides for a different reason (more on that later, I hope…). Craig’s method of synthesis involves a reaction between a silver carboxylate and an amide. The evidence collected by the Hutton lab points toward intramolecular attack shown below. The relatively weak linkage here is put together at the expense of the stable Ag-S bond. It remains for me to add that this peptide bond-forming method works in the so-called N-to-C direction, which is way less common than the other way around.