Arrheniusthegreat - 8-2-2013 at 12:41
So, I've done some searching around the forums and I can't find any direct answers to this because it all seems to be 4-methoxyphenol from other
reagants. I can't seem to find anything as far as literature goes, but then again I'm not too good at searching and finding things around here
apparently. So here's what I'm curious about,
1. How do I go from Anethole--> 4-MeOphenol? Do I get an intermediate of Anisealdehyde? I surely spelled that wrong but I'm sure you know what I
mean.
2. Would all this be easier to start from phenol?(Could someone pm me about salicylic acid--> phenol? I know its on here somewhere if you could
just direct me because I can't seem to find it. Yes I looked for like 30 minutes, if thats lazy well.. whatever.)
3. The last but most important part, what would be the easiest way to prepare 2-methyl 4-methoxyphenol? (It's not the same as just 4-MeOphenol
right??
)
I'm obviously not too informed on this subject matter, but I've a good grasp of running oxidations, condesations, etc etc.
Scr0t - 10-2-2013 at 04:09
The easiest way to 4-Methoxyphenol is monomethylation of Hydroquinone using MeOH/H2SO4/p-Benzoquinone.
Can't you get Hydroquinone?
To convert anethole you could try these
http://www.erowid.org/archive/rhodium/chemistry/benzaldehyde...
http://www.erowid.org/archive/rhodium/chemistry/ba2phenol.ht...
One way to 2-Methyl-4-methoxyphenol...
Formylate 4-Methoxyphenol with Mg/Paraformaldehyde or Reimer-tiemann reaction to give 5-Methoxysalicylaldehyde.
Reduce the carbonyl with a Clemmensen reduction.
Another way could be...
Toluene -> 2-Nitrotoluene (nitration followed by laborious separation of isomers)
2-Nitrotoluene -> 3-Methyl-4-aminophenol (reduction with Al/H2SO4, US2446519, 74% yield).
Protect the amino group by acetylation of the 3-Methyl-4-aminophenol by heating with AcOH to give the N-acetyl derivative (Vogel 3rd. Ed. p577-578).
Methylate the phenolic group.
Hydrolyze the acetyl group to deprotect the amine with aqueous HCl.
Perform a Sandmeyer reaction with NaNO2/HCl to convert the amino group to a phenol.
[Edited on 10-2-2013 by Scr0t]
crazyboy - 10-2-2013 at 13:56
A : Anisaldehyde from anethole via oxidative cleavage: 20 g anise oil was
suspended in a mixture of 150 mL water and 30 mL conc. sulfuric acid; addition of
55 g sodium bichromate at such a rate that the temperature did not exceed 40°C.
The reaction mixture was extracted with 4 x 125 mL toluene and the solvent evaporated. The residual oil was vacuum distilled to yield 9.1 g
anisaldehyde.
B : O-formyl-4-methoxyphenol: 6 mL anisaldehyde was dissolved in 75 mL
dichloromethane (DCM). A mixture of 12 g hydrogen peroxide and 10 mL conc.
formic acid was added over 30 min. The reaction mixture was gently refluxed for 21 h.
C : 4-methoxyphenol: Evaporating the solvent from reaction mixture and taking
up the residue in 100 mL aqueous NaOH (20%) (25 mL MeOH as co-solvent)
yielded 4.1 g 4-methoxyphenol as a white crystalline product after the usual
work-up and purification steps.
From
http://www.erowid.org/archive/rhodium/pdf/anethole.2c-b.pdf