In our Wiki it is mentioned that over time DMT N-oxide forms naturally from DMT FB over time because of exposure to air.

However, What direct evidence is there for this? Sorry if it is out there and I can't find it. The only hard evidence I can find of oxide formation so far is from metabolism or chemical treatment (e.g. peroxide).

Could there be a confusion here with DMT polymerization over time (NOT oxidation)? In this thread from benzyme polymerization of free base is discussed. Benzyme showed how it can be undone with TASA and Jees showed that it can be also be undone with an acidic water treatment.

We have an entry in our Wiki to convert N-oxide into DMT FB. Could that instead really be about de-polymerizing with an acid step? If so the zinc would not be required to go from goo to xtals.

Practical detail: there was betterment in 1 experiment (like 50% orange goo -> crystals) in a process where {redissolving in acetic acid} was a part of a zink reduction. Tests are needed for asserting a claims about the role of redissolving on it's own without the zink stuff.

This is exactly what you did with the vitC + citric acid in post #24, instead of my vinegar try, and clearly had better result than my 50%.

I also think there is no relevant transformation N -> N-Oxide at regular conditions. It only forms in contact with O2-radicals and these occur quite to a lesser extent if no UV-rays are present. This means in no direct sun that reaction should be slowed down super much and in dark enclosed cavities there seems to be no transformation for years?

So you would really have to force it by placing your goodies in direct sun, otherwise there seems to be no reaction?

Thanks Jees. To clarify those experiments:

With post #3 and #4, you discovered that doing several acid/base treatments "de-polymerized' the goo to the point of making 23% of it xtals (a very important observation). With a later zinc + acid + stirrer (post #15) you found 50% "depolymerization". We don't know if the difference is because the zinc helped de-polymerize DMT or if it was simply because of the action of acetic acid breaking up the polymer slowly over time with a stirrer. However based on what I tested inspired by your finding of goo -> xtals, zinc is not neeccesary since a good conversion happened with acids + stirring and no zinc. As you say, we still really don't know if zinc would speed depolymerization up or not, but I guess it does not matter - I could be wrong that's just a guess on my part. Also, it looks like Benzyme had some success with tartaric acid (no zinc) in post #15.

If yields are better without zinc, it's even possible that zinc reduction stabilizes the polymer!

Is there anyone out there who can do something like solid-state NMR on a sample of goo? What other analytical technique would be most informative about the bonding state in the DMT goo?

Apparently indole aggregates can change luminescence. The more aggregation, the longer the wavelength (at least in the attached example, which I'm not sure would apply to DMT).

So when converting orange goo (aggregated DMT candidate) to crystals (less aggregated DMT candidate) using acid water (example), monitoring progress with a UV light may be interesting: orange goo may be red/green under UV right after dissolving in acid, and change towards blue or UV transparent while being "de-polymerized" by the acid over time.

For testing purposes, I think one can get the orange goo back from xtals using a concentrated basing step with high ionic strength + time. Heated naphtha seems to be needed to pick up the polymerized DMT which will crash as orange oil before xtals when cooling.