DPT synth via propyliodide and ethanolamine

[Bandil]

Hi!

Swim was pondering the synth of DPT, using tryptamine and propyliodide. Shulgin uses some quite exotic catalyst for this reaction. Can anyone explain what it actually does?

I also read about people using ethanolamine instead of the catalyst. Is this feasible for the DPT synth?

The full synth swim was thinking about was:

Tryptamine + propyliodide -> quad-PT
quad-PT + ehtanolamine -> DPT

What about yeilds, how are they? Would it be possible to do the reaction in one shot, by simply mixing all of the reagents?

Thanks!
Regards
Peter

[hypo]

i'm pretty sure that you are wrong.

quaternization seems not to be a problem with DPT (or anything higher than methyl). but you need a base to catch the HI or HBr formed in the reaction.

[Bandil]

OK, so you are suggesting that swim could do it with tryptamine + propyliodide + [Some Base] -> DPT? What bare would you suggest? Ammonia, triethylamine or what?

Thanks

[hypo]

well, i would suggest diisopropylethylamine, but only because shulgin uses it in tihkal, not because i understand this chemistry stuff.

ammonia is obviously bad, because you don't want to alkylate your base, do you? i guess the more sterically hindered, the better.

there's also some stuff in tfse about using PTC/NaOH.

[Rhodium]

Any sterically hindered tertiary amine should work, triethylamine and trimethylamine would probably just be alkylated. Hünig's base (diisopropylethylamine) is perfect - it is not nucleophilic at all.

[UTFSE]

how does one make ethanolamine (sounds like ethyl and a amine) ?

I haven't found a straight forward synth from looking around.  

this is a pre to morpholine.
OTEECEE & meeeee!!!!

[Rhodium]

Addition of ethylene oxide (oxirane) to ammonia. But ethanolamine is so cheap it is unnecessary to make it yourself.

A ghetto variety would be to react ethylene glycol with HCl to get 2-chloroethanol, which is then reacted with ammonia to give a mixture of mono-, di- and tri-ethanolamine.

[Lilienthal]

The ethanolamine route does work only for methylations if I remember correctly.