Hi Savio,

Use dry chloroform or dichloromethane as a solvent in the column put alumina. Good luck

There isn't enough information. Although these are very polar compounds, the rest of the molecule also contributes to the chromatography. Small molecules may need to be purified via HILIC. Molecules with more organic groups are less polar overall and can be purified with weaker solvents.

What have you tried already?

Currently i do a tlc at 50 % which removes impurities but the desired N-oxide is stubborn, i change the solvent system to DCM;Methanol and at 5 % methanol:DCM i start getting compoind but on complete elution of column i get my product.