Hello,

I have tried loading pro as the first amino acid on to the 2-chlorotrityl chloride resin (CTC) with no luck. I have performed both using manually synthesis and tried using the synthesizer for loading and synthesis. For both methods I have done double coupling, but the Pro was not coupled to the CTC, even when I've tried doing the first coupling for 3 hours.

Others members of my groups used the same CTC for their synethsis and had no issues with it.

It could be due to the unique characteristics of Pro that it might need a specific method-

How can I get a proper coupling of the Pro to the resin?