Jan e Kharabat
Established member
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I've been working on 2C-B purification for a while and have discovered many interesting things. I had a very dirty sample, just to make things more challenging. I tried acetone and IPA washes which work well but only to a limited extent, I also tried re-x from IPA which didn't do much either. Then I tried mini A/B using NaOH and DCM as a solvent, it worked much better but resulted in significant yield loss (you have to be careful about the pH, which I wasn't...) DCM is problematic on its own.
Then I stumbled upon something interesting. I dissolved the salt in a small amount of water, added NaCO3 and left it for a while. When I came back, a layer of solid had settled at the bottom. I knew that 2c-b freebase can solidify, but from the NaOH solution it only crashed out as an oil. So I poured off the aqueous solution, dissolved the solids in IPA, filtered, added FASI, and fumarate crystals crashed out after a while! Repeating the process a couple of times gave very pure crystalline powder which I re-xed from water to get beautiful shards.
So to sum it up,
- dissolve the salt in a small amount of water.
- add a good amount of NaCO3
- wait a couple of hours for the freebase to crash out and solidify
- pour off the aqueous solution
- dissolve the solids in IPA and filter to remove the insoluble matter
- add FASI and let it stand for a few hours
- once the fumarate crystals have crashed out, pour off the mother liquor, and wash with a small amount of fresh IPA
- redissolve the fumarate in a small amount of hot distilled water and let it stand for a few days or weeks until the water has evaporated and the big beautiful shards have formed.
Also, I think it forms a di-salt with fumaric acid. I weighed the fumarate, converted it into freebase, weighed the freebase and it was much more than the calculated supposed weight, but it was almost identical to the calculated weight using half of the molecular weight of fumaric acid.
Then I stumbled upon something interesting. I dissolved the salt in a small amount of water, added NaCO3 and left it for a while. When I came back, a layer of solid had settled at the bottom. I knew that 2c-b freebase can solidify, but from the NaOH solution it only crashed out as an oil. So I poured off the aqueous solution, dissolved the solids in IPA, filtered, added FASI, and fumarate crystals crashed out after a while! Repeating the process a couple of times gave very pure crystalline powder which I re-xed from water to get beautiful shards.
So to sum it up,
- dissolve the salt in a small amount of water.
- add a good amount of NaCO3
- wait a couple of hours for the freebase to crash out and solidify
- pour off the aqueous solution
- dissolve the solids in IPA and filter to remove the insoluble matter
- add FASI and let it stand for a few hours
- once the fumarate crystals have crashed out, pour off the mother liquor, and wash with a small amount of fresh IPA
- redissolve the fumarate in a small amount of hot distilled water and let it stand for a few days or weeks until the water has evaporated and the big beautiful shards have formed.
Also, I think it forms a di-salt with fumaric acid. I weighed the fumarate, converted it into freebase, weighed the freebase and it was much more than the calculated supposed weight, but it was almost identical to the calculated weight using half of the molecular weight of fumaric acid.
