Solid Phase Esterification
This method describes the esterification of peptides in sequence with the coupling of the terminal residue, a hydroxy acid, onto the next.
Step 1: Coupling of Hydroxy Acid onto Peptide
It's been found that standard coupling conditions/equivalencies are sufficient when coupling on a hydroxy acid.
- Rinse resin with DMF (3x), followed by swelling with DCM (3x)
- Dissolve hydroxy acid in DMF.
- Add DIPEA, followed by HOAt and HATU.
- Agitate for 45 min - 1 hr. and check on HPLC for completion
NOTE: Ionization of hydroxy acids might appear weaker in the MS.
Step 2: Esterification
NOTE: The esterification step requires dry technique.
- Swell resin with DCM and pull through with Argon.
- Add dry THF to resin and pull through with Argon.
- In separate vial, dissolve the next residue in dry THF. Then add in DMAP, followed by DIC.
- Allow the solution to react for 2-5 minutes.
- Add solution to resin, cap, and agitate for 1 hour.
page revision: 5, last edited: 07 Mar 2017 20:45