[Dodecanone]

Hello, chemical forums. I'm having an issue with a reaction to the lab so I thought I'd bring it to a larger population than just my labmates.

I've been running a condensation reaction on a reduced alpha-amino acid  (so the diamino alcohol) to form the diimine. In the past, imines have been almost "eager" to form! This diimine, however, is proceeding quite slowly, if almost not at all.

The condensation is acid catalyzed and I have drying agent in the flask to pick up water when it forms to try and push the equilibrium towards completion. 48 hours later and the TLC shows very little of any product formation (lots and lots of starting material remains).

Any insight or advice from the professionals or other graduate students out there? I'm at a loss...

[discodermolide]

Do not trust imines and TLC, they are usually not at all stable to silica gel and all you see is starting material.
Use NMR perhaps of backs alumina if you really need TLC. Otherwise just run your next reaction and see if you get the desired product.

[OC pro]

Dean-Stark apparatus and heating?

[opsomath]

I was also going to suggest Dean-Stark and azeotropic H2O removal. It's amazing how much drying agent won't do.