Hi. i have a molecule it has both amide and ester bond. When i want to get second amide bond with ester part of the molecule by an amine, but it attacks to the amide bond also. In which conditions (temp, solvent, catalyst etc.) i can protect the first amide bond and make aminolysis reaction favour.
First, perform ester hydrolysis using LiOH in aqueous THF at room temperature for 4 hours. To isolate the resulting acid derivative, carry out an extraction with DCM and water. The acid, now in its salt form, will be water-soluble. Separate the aqueous layer and acidify it using HCl. The acid may precipitate out; if not, extract it again, at which point the acid will be in the organic layer.
Next, proceed with amide coupling. Use HATU as the coupling reagent, combining your acid with the amine of your choice at room temperature overnight. This should complete the desired synthesis.
Dear Youssef, i tried it with different coupling agents and it worked. But reaction path has longed and so yield has been decreasing. Also coupling agents are expensive. I want to do direct amidation from my ester intermediate. May be i need to try it with different solvents and with different catalysts. If i cant proceed, as you offer plan B is ready.
- Badges
- Science topic