Now SWIM's primarily interested in demethylating vanillin since it was his impression that eugenol is very hard to deal with.
You are suggesting that your impression is that the demethylated eugenol is less stable than the demethylated vanillin? Is this correct?
Method for dealkylation of alkyl-aryl ethers
Patent US4695659 (http://l2.espacenet.com/dips/viewer?PN=US4695659&CY=gb&LG=en&DB=EPD)
A method is disclosed for the dealkylation of alkylaryl ethers by reaction with aluminum triodide under reflux. The reaction is carried out in the presence of a catalytic amount of a quaternary ammonium iodide in a substantially non-aqueous organic solvent. The reaction product is then hydrolyzed with water. The quaternary ammonium iodide can be of the formula R4N+I-, wherein R is alkyl, and the solvent is preferably benzene or cyclohexane. (In their claims they say that toluene or xylene also work, but give no examples/yeilds.)
EXAMPLE 1
Aluminium powder (2.5 g, 93 mmol) and iodine (19.0 g, 150 mmol) were mixed in 130 ml benzene (or cyclohexane) and were refluxed until the red colour of iodine disappeared (about 1.5 hours). The mixture was cooled. A solution of anisol (phenyl-methyl ether, 5.4 g, 50 mmol) and n-Bu4 N+ I- (tetra-n-butyl ammoniumiodide, 0.05 g, 0.14 mmol) dissolved in 25 ml benzene (cyclohexane) was added dropwise. The mixture was heated and was refluxed for 20 min, then cooled and hydrolysed with 150 ml water. The organic phase was separated and the water phase was extracted with 2.times.25 ml diethyl ether. The organic phases were collected and were extracted with 30 ml 2 molar NaOH. The water phase was separated, acidified with concentrated HCl and was extracted with 3.times.25 ml diethyl ether. The organic phases were dried (Na2 SO4) and were evaporated to give pure crystalline phenol. Yield=99%. M.p. 41 DEG-42 DEG C.
Vanillin to 3,4-Dihydroxybenzaldehyde
Solvent-benzene
AlI3/ether molar ratio-4.8
ether/R4NI molar ratio-360
Time(hours)-1.5
Yeild(%)-88
Isovanillin to 3,4-Dihydroxybenzaldehyde
Solvent-benzene
AlI3/ether molar ratio-4.5
ether/R4NI molar ratio-120
Time(hours)-1.5
Yeild(%)-84
Interesting Selective Demethylation
2,4,5-trimethoxybenzaldehyde to 4,5-Dimethoxysalicylaldehyde
(4 different)
Solvent-cyclohexane
AlI3/ether molar ratio-1.5, 3.3, 5.5, 10
ether/R4NI molar ratio-100, 100, 100, 50
Time (hours) -14, 1.5, 1.5, 10
Yeild(%) -88, 90, 91, 85
Those who give up essential liberties for temporary safety deserve neither liberty nor safety
However, since the mechanism of apomorphine formation starts by protic attack at C-14, then a chain reaction ensues which transfers thru the C-7,8 double bond SWIM believes this can be circumvented by reducing the 7,8 double bond.
This explains why there are processes for demethylating oxycodone using hydrobromic acids.
The yields are low (35%) but it works.
On poppies.org there was a discussion called "hypothetical hydromorphone failure"
Where a guy catalytically rearranges codiene with Pd black in HCl, then goes on to demethylate it with hydroiodic acid.
At first he fucked it up, but on the second try he got 15%
Yeilds, and if you look closely at how he did it he was sloppy.
Because he refluxed it too long (1 hour), and in most journals they specify 15 minutes at 135 degress centigrate, add the dihydro (phenanthrene) whatever, when the acid (48% HBr) reflux is underway and not before, etc.
So it the personal conviction of SWIM that codeine can conveniently be converted to hydrocodone, then hydromorphone, using very accessible chems, an opiate for the masses type mission.
The link for that thread is:
http://www.poppies.org/foru/DCForumID16/143.html (http://www.poppies.org/foru/DCForumID16/143.html)
I think there is another possible side reaction in this case
(H-X) demethylation, that could screw things up.
That is, H-X cleavage of the oxygen bridge on the phenanthrene skeleton to the catechol.
See:
Rice,K.C., J.MED.Chem., (1977),20,164
For details.
He also rambles on in that thread that he tries to demethylate hydrocodone with pyridine.HCl and got a discouraging 5-7 %, so that`s a no go.
If you were to use any method to prepare hydrococdone that gives anything less than quantitative yields from codiene SWIM would recommend that you seperate unreacted codiene from the hydrocodone by forming bitatrate salts of the two.
codiene bitartrate is water insoluble, hydrocodone bitartrate is water soluble, hence seperation.
If you overshoot the tartaric acid in this titration you`ll get tartrate salts which are both soluble, hence no seperation.
Failure to do so in this case will result in you blowing chunks for some time.
(Gee blowing chunks was never this fun !)
Regarding pyridine via decarboxylation of aryl type acids
See: "copper quinoline decarboxylation of aromatic acids"
Nilsson M., Acta. Chem. Scand. 1966, 20, 423-426
Any more info on this would be welcome.
Spisshak Out!
Got the tough shit response when I tried that link, hope this fixes things.http://www.poppies.org/forum/DCForumID16/143.html (http://www.poppies.org/forum/DCForumID16/143.html)
Aluminum foil works well, but iron/steel turnings are much cheaper, and work better Post 228769 (https://www.thevespiary.org/talk/index.php?topic=6827.msg22876900#msg22876900)
(lugh: "Re: proper waste disposal", Chemistry Discourse) :)
Can you provide the reference to this it sounds interesting.
I don`t care if it is Russian, I can have this translated..
Dear Spisshak!
Diafrag asked me to translate the reference for you to avoid any possibility of mistake. It's (i'm not quite certain myself if that's the proper name :) ) -
Applied biochemistry and microbiology, v. IX, 1, p. 138
or, as transcripted from Russian -
Prikl. Bioch. i Microbiol., <et cetera>
I am also looking forward very much to seeing that article, BTW!
Great job, Diafrag! ;)
Antoncho
http://www.chemlover.narod.ru/articles/article16.djv (http://www.chemlover.narod.ru/articles/article16.djv)