05-08-04 00:19
No 505668
I have this thought about the synthesis of alpha-substituted amines. You might know of some that are interesting.
My thought is this: If there were an easy way to oxidize the amino functionality to a nitro group, the alpha-alkylation could proceed via a nitroaldol (Henry) route, followed by acid-catalyzed dehydration of the resulting alcohol, and then simultaneous reduction of the double bond and of the nitro group back to an amino.
An example might be:
Step 1: Tryptamine --(unknown process)--> Nitro analogue
Step 2: Nitro analogue --------(LDA)--------> Nitro analogue enolate
Step 3: Nitro analogue enolate ---(acetaldehyde)----> Beta-hydroxy alpha-ethyl nitro analogue (BHAENA)
Step 4: BHAENA ----(excess acid)----> Alpha-ethenyl nitro analogue (AENA)
Step 5: AENA -----(H2, Pd)--------> Alpha-ethyl tryptamine
That was a lot of terminology which I'm not sure I'm using correctly. Pictures follow:
Hopefully what I'm proposing is now clear enough. Questions for discussion:
1. Does anybody know how to do the amino-to-nitro oxidation bit?
2. Does anybody see any major problems with the rest of the plan?
(Newbee)
05-10-04 13:27
No 506182
Acid won't do for the dehydration when the product is not conjugated with an aromatic system, you need phtalic anhydride.
I had the same idea on amphetamine synthesis from PEA's some time ago, but let's face it, the route has too many steps and the yield would probably be low if it worked at all. There are better ways to alpha-alkylated amines.