This is a reply to https://www.dmt-nexus.me...aspx?g=posts&t=67539
I can't reply due to limited membership so hope this info reaches the right people so they can test or perhaps correct me if I have read this paper incorrectly.

Found this paper with Tetrahydroharmine (THH) pKa 15.6

The pKa of Harmine and Harmaline are different but they are not freebase form so maybe that is an explanation for the discrepancy?

Thats the deprotonation pKa
Its an interesting paper, basically they mixed THH with So Much lye that the freebase alkaloid behaved as an acid and formed a water soluble potassium salt. As it turns out, that hydrogen on the indole nucleus in ß-carbolines is distinctly more acidic than that in plain indole. So much so that it can behave as an acid in water solutions if a wildly excessive amount of lye is employed.
The moral of this paper, then, would be that while an excess of lye may be ok when basing THH a huge excess could be problematic.

Thanks for the post, Modern.

It seems the hunt continues!

I assume pKb is just as useful? THH pKb is 10.33

Tetrahydroharmine pKb sources
https://anoniem.org/?htt...cn/substance-175671.html

https://anoniem.org/?htt...und/inspect/CHEMBL129208

There is a 'pka graph' for THH on this page after clicking 'open all+' perhaps that is useful to someone that understands how to interpret the graph?
hxxp://www.chemicalize.org/structure/#!mol=%281R%29-7-methoxy-1-methyl-1H%2C2H%2C3H%2C4H%2C9H-pyrido[3%2C4-b]indole&source=recent

The chembase.cn database entry is obviously corrupt, a mixture of two entries, so I was ignoring it and the chembl entry, while matching the other, listed it as a theoretical value, so I figured even if the chembase pKb was for THH it was theoretical- which often doesnt match reality on these.

However! I had never found the chemicalize database before. I'm bookmarking this bitch Thanks modern.
According to that graph the intersect where half exists as the freebase is pH 9.11, which is clearly not the value spat out by the theorizer machine the other sites used. Moreover its value for the deprotonation of that indolic hydrogen is 16.30 which is similar to the 15.6 in that older paper. Working at such extremes of pH it wouldnt surprise me if the paper from the 80's was off by that much.
I think you found the real deal.

It also lists the isoelectric curves for all 3 of our harmaloids. Isoelectric point being where the maximum percentage of alkaloid should precipitate from solution. From those curves it matches the nexuses experience that baking soda should crash out harmine quite well while leaving much of the harmaline in solution. In the next comparison pH of 9 or just above should crash out most of the harmaline while leaving much of the THH in solution.
Ideas for doing that: Borax buffers to pH 9.2 and saturated calcium carbonate is pH 9.4

Can a PhD verify that I'm interpreting all this reasonably?