thors.lab - 14-10-2020 at 14:41
Hi, I've got a small sample of 2-FMA hydrochloride that I'm running TLC analysis on. The purpose of this experiment is to practice my TLC skills since
covid means I can't practice in lab at university.
I ran TLC on this using 100% EtOAc as the eluent and got two spots: one at Rf=0, and one at Rf=0.35.
With a molecule like 2-FMA, would you expect it to be sufficiently polar (since it's protonated) to stay at Rf=0? Or is it nonpolar enough what with
the whole phenethyl group to be what I'm observing at Rf=0.35?
Now spotting these polar compounds is proving challenging. Is it good practice to deprotonate 2-FMA before spotting? If I were to do a microscale LLE,
I would expect the deprotonated 2-FMA to migrate to the organic layer, and then I would expect it to be easier to separate. Yes?
Texium - 14-10-2020 at 15:19
You’ll want to deprotonate it and run it with the free base. The HCl salt will be too polar. Then try 20% EtOAc in hexanes or pet ether with a drop
of triethylamine added (if you have it) and see how that runs.