silica gel is acidic while you can get neutral alumina

thanks sir..

I propose to run the chromatography on basic alumina having pH of ~10.4. Under these conditions your molecule is expected to be stable. In my experience sensitive compounds degrade rapidly even if the elution time is reduced since the surface area of the pores bearing reactive sites is very large compared to the mass of the advancing molecules.

for choosing the right alumina see: https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma-Aldrich/Product_Information_Sheet/a1522pis.pdf