Hi all. After doing some reading on the use of amines as proton sponges, I thought I'd try a typical reaction using one. I happen to have a bunch of
vanillin, so I went ahead and used the erowid demethylation procedure with pyridine as a scavenger. To be brief, I began to wonder if piperidine or
piperazine would work better as scavengers due to both being saturated rings and piperazine having a second nitrogen. I got a good deal for
piperazine-based deworming medication on ebay. I later received two bottles of piperazine citrate in water with a bunch of sugars and preservatives
which I obviously don't want. The plan was to freebase the piperazine and then distill, but unfortunately my condenser just died. Is there any other
way to separate the freebase from the aqueous solution (i.e. an insoluble adduct or alternative solvent)? mackolol - 18-5-2020 at 00:11
It's very hard to separate such mixtures without distillation. All I can suggest you is to buy new condenser and try to distill it, You'll need the
condenser anyways.draculic acid69 - 18-5-2020 at 00:42
You can extract the alkaline mixture with a non polar and then dry it and gas it if u r after the HCL saltkarlos³ - 18-5-2020 at 04:02
Pyridine is more than just acid scavenger in that reaction.unionised - 18-5-2020 at 09:27
The aldehyde group will react with the secondary amines.
If you had dimethyl piperazine it would be interesting.G-Coupled - 18-5-2020 at 10:10
Pyridine is more than just acid scavenger in that reaction.
How so? Catalyst?
Pyridine, but only as it forms one of its hydrohalogenide salts by reaction with the dry aluminium salt, is the active demethylating reagent, as far
as I understood it.
We all know how pyridine HCl is used for that purpose, I understand it like that it will form in-situ, and thus be the responsible reagent to result
in that reaction.
I doubt it can be replaced with either piperazine or piperidine.
As far as I know, it has something to do with pyridine being a tertiary amine and won't work with those two secondary ones.
On the other hand, it will work with triethylamine instead, but just worse.
Good luck with the piperazine isolation!
I read it is quite annoying and not easy.
But as soon as you have the dihydrochloride salt, treat it carefully.
When you prepare the monohydrochloride for a monoalky-/acylation, you should really take care to get the other molar half that acts as acid scavenger
during that process out afterwards.
It will precipitate as diprotonated salt after the reaction under cooling, so filter that and keep it for later reactions on hand.
Without using any other base as acid scavenger, the piperazine itself will fill in that purpose.
