Zn(BH4)2 can be useful when it comes to reductive permethylation of amines using paraformaldehyde or equivalent, but that is not useful in this case. Good for making DMT out of tryptamine though.

Did our PimpMaster make a useful comment back in his foolish youth ?

--psyloxy--

Author
                         Topic:   What did he not-do this time?
    KrZ
    Member
                            posted 11-16-1999 06:03 PM          

                         Well, I came up with a good use for all that leftover NaCNBH3 you might have laying around.

                         "Tryptophan (454g) was suspended in tetralin (1150 ml) containing acetone (12.9 g) and the mixture was heated
                         to reflux for 12 hours with vigorous stirring until no more carbon dioxide was evolved and the reaction mixture
                         became clear. The solvent was removed under vacuum, and the residue was distilled under reduced pressure to
                         give a yellow crystalline solid. (from rhodium). Next 30g of formaldehyde and 120g Tryptophan were disolved in
                         1800ml of MeOH, to this was slowly added dropwise 50g of NaCNBH3 disolved in 550ml MeOH. Then 14g Glacial
                         Acetic Acid was added dropwise with stirring. The mixture was then stirred for 60 hours. The majority of the
                         MeOH was distilled off (2L collected) to the distillation flask was added 1L of 5% Aq. Ammonia which was
                         extracted with 3x 250ml of DCM. The DCM was washed with a salt solution (not saturated but still pretty strong)
                         then the DCM seperated and dried with a large portion of MgSO4 made by dehydrating epsom salts overnight in
                         the oven at 450C (the rock-solid mass had to be pounded into a powder with a hammer and the small remaining
                         clumps ground in a pestal, quickly so as not to allow H2O uptake from the atmosphere). The DCM was distilled off
                         at atmospheric and then the distillation was continued (~1 torr now) until the dimethyltryptamine was collected.
                         Which was recrystalized from boiling hexane with a few mls of Ethyl Acetate added (these were the 2 hardest
                         things to get!) This afforded 48.8g of DMT, a 35% yield. Not high but it was still a fun adventure. The DMT was
                         immediately mailed 3500 miles away."

                         Found this (yes again) at a desk in the library, looked like there was a stack of journals next to it as well.
                         Amazing the detailed notes ppl leave in the library here.
    psychokitty
    Member
                            posted 11-16-1999 10:20 PM          

                         Like I said, you ARE the MAN. It goes without saying that I'm impressed. You're definitely paving the way to
                         success for many of us.

                         --PK
    Slappy
    Moderator
                            posted 11-17-1999 01:23 AM          

                         I think he not-meant Trptamine, not Tryptophan in the second step.
    KrZ
    Member
                            posted 11-17-1999 08:22 AM          

                         Heh, yes tryptamine indeed. My mistake.
    Rhodium
    Administrator
                            posted 11-17-1999 11:15 AM          

                         I thought tryptamine cyclized to a beta-carboline on attempted methylation with formaldehyde? But you should
                         know if it was the real stuff you got.
    Bright Star
    Member
                            posted 11-17-1999 11:32 AM          

                         Bra-fuckin-vo.

                         Anyone know how to paste PGP into Hushmail?
    KrZ
    Member
                            posted 11-17-1999 12:22 PM          

                         J. Med. Chem., 1995, Vol. 38, No. 18 pg 3577. half-way down the page "The general method for dimethylation of
                         indoleethylamines is illustrated below for
                         (S)-N,N-dimethyl-2-[5-[(2-oxo-1,3-oxoazolidin-4-yl)methyl)-1H-indol-3-yl]ethylamine."
    KrZ
    Member
                            posted 11-17-1999 12:35 PM          

                         You should just be able to export your key to a text file, select and paste, and then do the same with any
                         message you might want to send? Is something not working? Works fine on other free-web-mail servers. Why
                         would tryptamine cyclicize? How exactly does that mechanism work?
    Rhodium
    Administrator
                            posted 11-17-1999 03:16 PM          

                         I don't know the mechanism, but it is called "Pictet-Spengler cyclization". After a formaldehyde molecule has
                         added to the side-chain nitrogen, the other end of it bites the 2-position of indole, water is liberated and you
                         have a betacarboline instead of a tryptamine... It is acid catalyzed and it only takes place in solutions with a pH
                         < 7.
    KrZ
    Member
                            posted 11-17-1999 05:30 PM          

                         I see now, in the notes above they said they used 14g GAA and the freebase of tryptamine. That 14g isn't going
                         to make the reaction mix very acidic. This does occur at pH < 7, but the optimal rate is acheived at lower pH? If
                         so then perhaps cyclization is kept relatively low. No pH testing was done in the notes for this reaction, if only
                         they had kept tabs we could have the answer :-( Even in the sample reaction below they only reported 52%
                         yield, a good sign.
                         http://orgchem.chem.uconn.edu/namereact/pictetspengler.html 

Zn(BH4)2 and NaBH3CN are both good for reductive amination. The only problem with the reductive amination of tryptamine with formaldehyde is that Pictet-spengler side reaction which occur at low pH. Follow KrZ's example above and don't make the mixture too acidic, and you will probably minimize this competing reaction.