uemura (Hive Photographer)
01-31-02 11:17
No 263157
      Confirmation needed...  Bookmark   

In ../rhodium/chemistry /345-tmb.html the preparation of Syringaldehyde starting from 5-Bromovanillin is described (for which nasty bromine needed). Simple question for the Hive Bees:

Instead of the 5-Bromovanillin, it should be possible to use 5-Iodovanillin (much less nasty iodine needed) in this metylation rxn.

Is this correct?

Thnxs and
Carpe Diem
 
 
 
 
    Rhodium
(Chief Bee)
01-31-02 11:31
No 263169
      Re: Confirmation needed...  Bookmark   

Yes definitely. The yields should be higher, too. Just adjust for the molecular weight of iodovanillin vs. bromovanillin.

Don't forget the DMF-less variation of this reaction in ../rhodium/chemistry /mmda.mescaline.html :

5-bromovanillin (5mmol) is refluxed with EtOAc (3mmol) and CuBr (1mmol) in 5 M NaOMe/MeOH (10 ml) for 14 hours. Classical work-up (addition of water and acidification followed by extraction of the phenol) leads to pure syringaldehyde (95%). When starting from the more soluble 5-bromovanillin dimethyl acetal, reaction is achieved within 2 hours (yield 98%). Preparation of this acetal is probably not worth the extra work.

What was your method for producing the 5-iodovanillin? Don't forget to post your results for the methoxylation of iodovanillin when you're done.
 
 
 
 
    uemura
(Hive Photographer)
01-31-02 12:04
No 263183
      Re: Confirmation needed...  Bookmark   

Rhod,

Sure, all details and results will be provided. Now, since a simple route to the trimethyl phosphate for methylation is on the horizon (uemura will try to make some this weekend), the idea is to follow:

1) vanillin -> 5-iodo-vanillin from United States Patent 4,465,864 (99% yield)

2) 5-iodo-vannillin -> syringaldehyde (95% yield, see your post above)

3) syringaldehyde -> 3,4,5 trimethoxybenzaldehyde (92% yield)

From: ../rhodium/chemistry /me3po4.html
In an apparatus similar to Example 1, 15.2 g (0.083 mol) of syringaldehyde and 15.0 g (0.11 mol) of potassium carbonate were heated to 105C under nitrogen and 15 ml (0.12 mol) of trimethyl phosphate were added over 10 minutes. The mixture was maintained at about 80 C. for 3 hours then cooled to 45 C. and quenched with 50 ml of H2 O. The tan solid which precipitated was collected, washed with 350 ml of water and dried to give 15 g (92%) of 3,4,5-trimethoxybenzaldehyde.

4) 3,4,5-trimethoxybenzaldehyde -> 3,4,5 trimethoxynitrostyrene (a la Slotta would give 50%+ yield)

5) 3,4,5 trimethoxynitrostyrene -> 3,4,5 trimethoxyphenylethylamine (a la sunlight, yield say 50%+)

and BINGO....... smile

P.S. the most likely non-OTC chems needed for 1-5 are iodine, p2o5 and MeONa. For the last one foxy2 or Antocho digged out a patent for preparing sodiummethylate solutions.
Carpe Diem
 
 
 
 
    Osmium
(Stoni's sexual toy)
01-31-02 12:23
No 263193
      Re: Confirmation needed...  Bookmark   

Iodine is MUCH more expensive than Br2 though!

Anybody remember the solventless methylation reactions using dimethylsulfate? Yields were supposed to be even higher (just curious if anybody has it bookmarked, too lazy to search myself)
 
 
 
 
    uemura
(Hive Photographer)
01-31-02 12:39
No 263201
      Re: Confirmation needed...  Bookmark   


Iodine is MUCH more expensive than Br2 though!



But it doesn't stink that much! Just don't want to destill these nasty bromine fumes which don't want to condense.


Anybody remember the solventless methylation reactions using dimethylsulfate?



Same ref as the one with the Me3PO4: ../rhodium/chemistry /me3po4.html


Carpe Diem
 
 
 
 
    Osmium
(Stoni's sexual toy)
01-31-02 12:41
No 263202
      Re: Confirmation needed...  Bookmark   

Ooops!
 
 
 
 
    TranceMe
(Hive Bee)
02-01-02 04:19
No 263516
      Re: Confirmation needed...  Bookmark   


Iodine is MUCH more expensive than Br2 though!



Dunno the price of Br2 in your neighbourhood Osmium, but I got mine today (yup OTC where I am) for $90/kg. Sublimated iodine 99%, little round pellets, 2-3mm in diam with a silver tone and a violet hue if looked with sunlight.

PD: paid cash, no papers, no questions.


Chemically enhanced.
 
 
 
 
    halfapint
(Ubiquitous Precursor Medal Winner)
02-01-02 09:34
No 263697
      Re: Confirmation needed...  Bookmark   

I got mine today (yup OTC where I am) for $90/kg. Sublimated iodine

You're connected. You gotta be hooked up. Must bee lots of seaweed around where you live...

~ ~ ~ C U N D C ~ ~ ~
~ ~ 4 / 20 / 003 ~ ~
1000000 heads high
 
 
 
 
    Osmium
(Stoni's sexual toy)
02-01-02 09:59
No 263707
      Re: Confirmation needed...  Bookmark   

> Dunno the price of Br2 in your neighbourhood Osmium, but
> I got mine today (yup OTC where I am) for $90/kg.
> Sublimated iodine 99%, little round pellets, 2-3mm in
> diam with a silver tone and a violet hue if looked with
> sunlight.

Yeah, exactly as I said, I2 is MUCH more expensive than Br2! I certainly can get Br2 for much less than $90, or 100, and so should you.

1kg of I2 is about 4 moles. 200ml of Br2 would be 4 moles too. You can't simply compare kilo prices for I2 with the liter price of Br2 and then decide which one is the cheapest. Doesn't work like that.
 
 
 
 
    TranceMe
(Hive Bee)
02-04-02 06:06
No 264903
      Re: Confirmation needed...  Bookmark   

Osmium, you are right about the mole things. Besides I made a mistake when changeing to my currency. 1kg I2 was $54, and NOT 90, sorryblush
However, just yesterday and following your advice, I got 250ml Br for $20 smile. Funny thing is that I went looking for HBr and the guy gave me a bottle which didn't state any conc. When I asked if it was 48% wink the guy had no clue. So he told me "Why don't you take bromine and dilute it as you like?" Ok...wink


Chemically enhanced.
 
 
 
 
    Rhodium
(Chief Bee)
02-04-02 12:57
No 265012
      Re: Confirmation needed...  Bookmark   

I bet half of the members here are envious of you having such a ignorant chem supplier near you... wink
 
 
 
 
    uemura
(Hive Photographer)
02-04-02 13:16
No 265017
      Re: Confirmation needed...  Bookmark   

All taking about money...smile
Just some remarks...
1) The NaJ (KJ) can be partially recovered and iodine regenerated
2) Working with bromine is much more hazardoeus than with iodine
Last one
3) a hobby is a hobby ....
 
 
 
 
    Sektor7G
(Stranger)
02-05-02 01:38
No 265226
      Re: Confirmation needed...  Bookmark   

Just a small question, what are some common uses for 5-Iodovanillin ?
 
 
 
 
    Osmium
(Stoni's sexual toy)
02-05-02 11:41
No 265405
      Re: Confirmation needed...  Bookmark   

There are no common uses. Only use for it is as an organic intermediate for research or small scale pharmaceutical production. I don't think you will be able to find a company with iodovanillin in their name which produces that stuff regularly, in bigger than a few kilogram amounts. And if there is one then they are most likely producing it for only very few industrial clients for use in a specialised process, and you won't be able to find them and/or buy from them.

Suppliers like Aldrich/Merck/Fluka etc will most likely custom synth it for you if you need 50 or so kg of it and are willing to pay their price, even if they offer that stuff in their catalogues I doubt they have tons of it in stock. Such rare intermediates are usually produced every few years by them, and when they run out they either produce another batch which will last them another few years or they will ask another company to do it for them since it's too much hassle to do it on their own.

I'm not fat just horizontally disproportionate.
 
 
 
 
    Rhodium
(Chief Bee)
02-05-02 12:04
No 265413
      Re: Confirmation needed...  Bookmark   

5-Bromovanillin is featured in Aldrich's latest catalog, at 44 for 25g. Considering that the vanillin, H2O2 and KBr needed for making it costs about 100 times less, I can't think of any reason to deal with the Sigma-Aldrich creeps.
 
 
 
 
    otto
(Newbee)
02-05-02 18:54
No 265526
      Re: Confirmation needed...  Bookmark   

hi uemura,

regarding your second step, afair the yield would be somewhat about 80%, the remainder being vanillin. iodine in organic compounds is easily reduced in presence of iodide (which will form as rxn goes on), thats why.
i think i've read the analogous reaction to give the hydroxy - compound somewhere on rhodiums site.

otto
 
 
 
 
    uemura
(Hive Photographer)
02-06-02 00:55
No 265654
      Re: Confirmation needed...  Bookmark   

Hi otto,
thanks for reply, Uemura has read the US patent avail on rh's site. Due to his 'extensive' search today, he's just running an Osmium/Rhodium AcOH-in-situ-bromation' run on vanillin. Things doesn't look bad. All stuff finished, cooling down for workup in the morning...