[nj_bartel]

I'm attempting to devise a route to synthesize dopamine from L-DOPA, but I'm having trouble.  I haven't been able to find a reaction that cleaves a carboxylic acid and other routes I've looked into look like I might need to protect the alcohols on the bezene, which I'd like to avoid doing.  Does anyone have a direction they could point me in?  I'm looking to actually run this, so no directions that lead to me needing highly controlled substances please 

http://img291.imageshack.us/img291/4455/dopaminesynthesiswz7.jpg

^L-DOPA => Dopamine

Thanks =]

If anyone has an idea for a tryptophan => serotonin route, that would be equally useful to me, but I haven't looked into it much because the chemistry of indole is unknown to me.

[nj_bartel]

Ok, found decarboxylation.  Is there any way to predict the temperature at which a carboxylic acid will break off into CO₂?  Or if I were to do it, would slow heating until I see bubbles form be a satisfactory way to determine if the carboxylic acid is cleaving?

Thanks.

[macman104]

I would imagine the slow bubbles would be a good indication of the CO2 production, I'm not really sure how you could predict temperature unless you found a paper that did the decarboxylation on a similar substrate.

[nj_bartel]

Ok, thanks.  One more thing about decarboxylations in general - as you have a heterogenous mixture, should it be stirred to suspension during heating?  That might make it difficult to identify bubbles.

[sjb]

If anyone has an idea for a tryptophan => serotonin route, that would be equally useful to me, but I haven't looked into it much because the chemistry of indole is unknown to me.

I think this is done effectively in vivo by tryptophan hydroxylase and some decarboxylase enzymes, but not sure about a non enzymatic route.

S

[ns9908]

Your body does this all the time. All it takes are some PDDIs (peripheral dopa decarboxylase inhibitors) to make it happen solely inside your brain (making it happen solely outside your brain is trickier [not to mention harmful] but some pyridoxine would help with that). Unfortunately most of them are prescription only. Fortunately, Internet!

[limpet chicken]

As far as tryptophan goes, if its 5HT and not tryptamine itself your after (oopsie, did I spill MeI in that flask before I started.. ), 5-OH-tryptophan is available in capsulated form in health food shops, and reflux in a high boiling point solvent with a ketone catalyst will give some yield, with some beta-carboline crap formed via pictet-spengler.

Just watch it with any alkylated derivatives that could cyclize to form a 1,1-disubbed harmine analog, as at least  1,1-dimethylharmine is a selective dopaminergic neurotoxin, gets oxidised to a charged species once it gets past the BBB, so can't get out again, and while its in there, fries the bejeebers out of ones DAergic neurones ala MPTP, and voila, instaparkinsons.

I apologise, for not posting the references, but I don't have access to my journal collection, or for that matter, my computer or mobile phone atthe moment, but its in a US forensic cland. chem. journal dealing with the byproducts formed by decarboxylation of tryptophan using peppermint oil and high-boiling nonpolar solvents , if. youwant a pointer on where to look, can't remember which, though, but best I can do at the moment