I am working with a molecule that has an NBoc protecting group. In my reaction, I am using HMPA as the solvent and heating the reaction mixture to 110 °C. I have noticed that under these conditions, I am obtaining two new spots, which I separated using column chromatography. However, upon analyzing the proton NMR spectra, I observed that neither of the isolated compounds has the characteristic 9-proton peak of the Boc group.

Is the NBoc group stable under these reaction conditions?