Well, re:'what happens with bromine,' the thought-train I'd been musing on used either iodine or bromine, and IMO was simpler...
I2 + tyrosine -> 3,5iodotyrosine + NaOH -> 3,4,5OHphenylalanine (which I kinda wanna munch in its own right - sounds like an interesting non-essential amino acid)
...and then, of course, decarboxylation in, say, thujone, a little MeI, and I think we all know what I delusionally believe would result...
...only *I* got the idea from :
http://www.ajinomoto.co.jp/ajinomoto/A-Life/e_aminoscience/bc/amino_18.html
...according to which, this whole damned chain should fall under the "idiot high school kid cooking in a jelly jar" level of difficulty... the first step is apparently damn-near-automatic, with all the reaction sensitivity of CO2 synthesis via NaCO3H + GAA...
...the article also asserts that Br2 would react identically to I2...
...however, I found this thread via a desperate search for better recrystallization info for tyrosine than this article gives - the H2O solubilities given, while they seem useable for small-scale recrystallization at first, have a simple problem - the solubilities of phenylalanine, which is also common in the same organic sources (lima beans, soy, sesame, almonds, etc...)
...U.S. patent 6,294,579 (no, I *don't* have the link, sorry) suggests that tyrosine is more soluble in alkaline than neutral solution, which may help - hot basic water -> cold salt water - but again, I don't know about phenylalanine's behavior...
...also, I don't know exactly how tyrosine/phenylalanine respond under blacklight - do they flouresce?
...I'm dirt-ass poor (actually, since you refer to both Cl and tyrosine as 'dirt cheap,' *beyond* dirt-ass poor), so these little tidbits are vital to a ghetto lab - I don't have the luxury of paying health food stores out the ass for precursor, and it would probably become a point of pride if I *was* wealthy enough - although I'd probably have better resources to do the deed with in such a case...
::sigh:: Naked in the woods,