Author Topic: Easy Route to DMT ?  (Read 5263 times)

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Rhodium

  • Guest
diphenylmethane and nabh4
« Reply #20 on: July 20, 2003, 02:09:00 AM »
The merit of diphenylmethane lies just in its high boiling point, I guess...

As for alternatives to NaBH3CN, there has recently been posted a method using NaBH4 in this forum, using low temperature and slow simultaneous addition of the hydride and formaldehyde from two separate addition funnels to make it work.

Rhodium

  • Guest
More about Tryptophan -> 3-Indoleacetaldehyde
« Reply #21 on: November 21, 2003, 08:35:00 PM »
Kinetics of Oxidation of Tryptophan by Sodium Hypochlorite
Thomas Rausch, Frieder Hofmann, and Willy Hilgenberg

Z. Naturforsch. 36B, 359-361 (1981)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/tryptophan.strecker.kinetics.pdf)

Abstract
The oxidation of tryptophan to 3-indoleacetaldehyde with sodium hypochlorite was investigated with 14C labelled DL-tryptophan. The reaction was performed under pseudo first order conditions. From the pH dependence of the reaction it was concluded that only the unprotonated tryptophan is converted to the aldehyde. The activation energy is 35±2.2 (SE) kJ x mol-1 as derived from the Arrhenius plot. Varying the pH between 8.5 and 11.0 and the temperature in the range from 298 K to 318 K did not alter the selectivity of the reaction as confirmed by TLC of the product (purity > 90%). A possible reaction mechanism is proposed.

Vitus_Verdegast

  • Guest
failed attempts to prepare indole-3-acetaldehyde
« Reply #22 on: June 16, 2004, 12:09:00 AM »
The route to indole-3-acetaldehyde by simple NaOCl oxidation of tryptophan has always intrigued me since it was posted here a couple of years ago. Granted, the dilution and amount of solvent used is huge, but in practice this takes only more time in the work-up, a price that is most willingly paid for what could be an OTC route to the dialkyltryptamine of choice. It is astounding that nobody has reported trials for what looks like a very straightforward route, even if indole-3-acetaldehyde is an unstable critter, it has worked for at least 2 different groups in the literature.


https://www.thevespiary.org/rhodium/Rhodium/pdf/indole-3-acetaldehyde.pdf


Two trials were made (by a famous Hungarian actor who appeared to me in a vivid dream  ;) ) using the above procedure, but substituting toluene for carcinogenic and thus restricted benzene.

From the first trial, after evaporating the red toluene extract in vacuo (fridge compressor, +- 50°C), a thick red oil containing orange solid material was obtained, that failed to produce a bisulfite adduct. This was, however, chalked up to inefficient stirring.

In the second trial, heavy overhead stirring was used, so that an almost uniform emulsion was attained during the whole process. Again, the toluene layer was deep red in color, and after concentrating the organic layer in vacuo using the same fridge compressor, a dark red oily residue was obtained instead of a yellow one like described in the above article. This formed a greyish brown solid upon treatment with a saturated bisulfite solution, which was washed several times with water. This was added to a warm sodium carbonate solution, stirred for 20 minutes and extracted with DCM.

The solid should have been washed with alcohol too, but that was forgotten by mistake.

After evaporation of the DCM, about 2 grams of a red oily residue was again obtained. This was diluted with ethanol, an excess of aqueous dimethylamine solution (containing 2 grams Me2NH) was added and the mixture was stirred for an hour in a cold water bath. A gram of NaBH4 was added in small portions while cooling the mixture in a cold water bath, stirring was continued for an hour, and the mixture was acidified with acetic acid.

Standard A/B work-up, extraction of the basic mother-liquor with DCM and evaporation of the solvent yielded... nothing but an unknown red-coloured solid which was certainly not the desired compound  :( .


Maybe it would help to add some kind of polymerization-inhibitor to the organic layer before adding the hypochlorite solution?


Lilienthal

  • Guest
Have you checked the pH?
« Reply #23 on: June 16, 2004, 12:49:00 AM »
Have you checked the pH? Maybe you could even lower the pH to 8 or 9 in order to prevent polymerization?

Vitus_Verdegast

  • Guest
yes
« Reply #24 on: June 16, 2004, 01:10:00 AM »
pH was 9 before addition of hypochlorite.

I was thinking maybe to dilute the hypochlorite solution even more, as it was stated that the dilution is necessary to avoid excessive coloring (polymerisation probably?) of the reaction mixture..


Sunlight

  • Guest
Anhydrous dimethylamine
« Reply #25 on: June 18, 2004, 12:51:00 AM »
May be the problem is the water in the imine formation ... Why the hell you didn't make a bit of anhydrous methylamine for that excelse moment ?

Vitus_Verdegast

  • Guest
because I doubted that I had the correct product
« Reply #26 on: June 18, 2004, 09:15:00 PM »
1. The miserable red goo I got instead of what should have been yellow as stated in the most recent paper, and colorless in the first 1950's Ann. Chim. one.

2. Surely it can not be even when using aqueous dimethylamine that no enamine at all is formed? Lower yields maybe, yes, Barium proved in the past that 40% aqueous methylamine works fine for reductive amination with phenylacetones.

3. I am very busy lately, and I should refrain from chemistry completely instead of trying things in a hurry  ::) .. Ahh, the call of the Sirens  ;)

I'll be back on top of this in a month or so, with anhydrous dimethylamine in alcohol, but meanwhile....

;)