TLC of three 4-position substituted psychedelic tryptamines

[nuke]

0.25 mm Silica glass backed plate run with butanol-acetic acid-water (12:3:5) for 2 h

All compounds were freebase. Approximately 500 ug - 1 mg of these compounds was solvated in 50 uL 1:1 methanol:acetone. Solvation was nearly instantaneous. 5 uL was removed and spotted on the plate.

Solvent front is at the top by the text, origin is the line at the bottom. UVL indicates that the spot had UV long wave absorbance or fluorescence.

All samples used were approximately 8 years old, with 4-HO-MiPT showing mild degradation and 4-AcO-DET showing much more degradation as a dark brown, clumpy powder. 4-AcO-DiPT had no visible degradation, and the TLC reflects this.

So, stuff to note here:
1) Both the 4-hydroxylated and 4-acetoxylated compounds have Rf values close to 0.5, showing that this solvent system is fairly ideal.
2) The 4-hydroxylated compounds have some absorbance in the visible light region and appear as grey spots on the plate; they are also very highly visible under short wave UV light.
3) The 4-acetoxylated compounds have very mild absorbance in the visible light region and appear as faint beige spots on the plate; these spots are very clearly visible under UVL light.
4) 4-HO-MiPT had two unique impurities or degradation products present, neither of which I'm terribly sure of. These two spots are extremely faint under UVL light and probably represent less than 1% of the total product. The lower Rf spot fluoresced orange under UVL light.
5) 4-AcO-DET had six unique impurities or degradation products present. One of these is 4-HO-DET, which was present in approximately equimolar quantity to 4-AcO-DET. Of the remaining impurities, the two closest to the origin exhibited UVL fluorescence, while the top two absorbed UVL light without fluorescence. It is expected that at least one of these is an synthesis impurity or degradation product N-acetylated on the indole ring. Although hard to see in the photo, another impurity was present as a brown stain at the origin which failed to migrate at all; this is probably some kind of highly conjugated polymer which resulted from degradation.
6) With 4-AcO-DET, the major products were 4-HO-DET and 4-AcO-DET, which I would estimate to be 90%+ of the material.
7) The 4-AcO-DiPT sample I possess is pristine, with no visible impurities.

Hope this helps someone out there!

 

[sekio]

Beautiful. Would a ninhydrin stain help visualise the spots?

 

[nuke]

Ninhydrin would reveal if any N-monosubstituted tryptamines were present, probably as synthesis byproducts. Ehrlich's reagent is ideal but I'm not sure if I have any DMAB laying around.

 

[Solipsis]

Great, so 4-HO-DET is showing right above 4-AcO-DET ?

I was looking for this info, for when I get around to investigating other esters than acetyls. It will come very handy, thank you.

 

[nuke]

Great, so 4-HO-DET is showing right above 4-AcO-DET ?

That's correct, it's the faint gray band which is not circled.

I'll also note that now, 48 h later, the bands for the 4-HO-tryptamines have now turned a very dark shade of gray, with yellow-green tinges at the edges of the spot. By contrast, the 4-AcO-tryptamine spots have turned light yellow-green. I'm guessing that they're rapidly oxidizing.

The migration is somewhat counter-intuitive; with silica plates usually the most hydrophobic compounds migrate the furthest, and we should expect that the 4-AcO-Ts would be more non-polar. However, it's clear from the Rf of 4-HO-MiPT versus 4-AcO-DiPT that the 4-AcO-Ts migrate less far than the 4-HO-Ts.

There was an erowid commentary on the TLC of psilocin/psilocybin, and it looks like the author mistakenly labeled the peak closest to the origin psilocin and the peak near Rf=0.50 psilocybin. I'm almost 100% sure he/she has it backwards after running this TLC.

http://www.erowid.org/archive/rhodium/chemistry/psilo-tlc.txt