I'm working on gelatin modification. To do this, the amine group was protected by BOC and the carboxylic group was activated by EDAC and NHS to form a stable amide bonds with another amino-content small molecule.
Now I need to remove the protecting group. As in the reference, they use the conc. HCl (0.5 % v/v to sample) at 4 degree Celsius to deprotect the BOC. But this spend about 2 weeks to reach the full deprotection.
I hope to fasten this process, I have found some papers such as using conc. HCl (0. 01% v/v) at 40 degree celsius take about 16 hours and HCl (4M)/dioxane at 0 degree celsius take around 30 mins for deprotection. Will these methods also break the amide bond of gelatin and the additional group that I'm grafting to the backbone? Anyone has experienced in this kind of reaction, please help !!!!
Can your gelatin handle high temps while dry? If so you can add a photo acid generator. Shine light on it, heat while dry and de protect. Commonly used in photoresists. Triphenyl sulfonium salts will work. You can buy them commercially.
look up papers by Frechet, Ito or Reichmanis
In peptide chemistry we routinely use TFA/DCM (trifluoro-acetic acid in dichloromethane). (http://commonorganicchemistry.com/Rxn_Pages/Boc_Protection/Boc_Protection_TFA.htm ).
There is no danger for amides.
Ioannis Hadjidakis thank you for your answer. But can I use another solvent instead of DCM, I think gelatin may not soluble in DCM
Gelatin is insoluble in DCM but soluble in TFA. However, you have BOC-gelatin (much more soluble in organic solvents) and so I expect there is no solubility problem by using a 50:50 mixture. The problem is that BOC-group is cleaved by dry acidic media in order to avoid any cleavage of other sensitive groups.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science