Author Topic: Variation on TiHKAL synth  (Read 6442 times)

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Re: Variation on TiHKAL synth
« Reply #20 on: February 24, 2002, 02:51:00 AM »
I've just been reading a comprehensive materials spec on methyl formate and there's a few caveats with using it: It decomposes in water in 8h, and in 24h in acetone. It is moderately toxic: 1.622g /kg ld50, 10000ppm of the vapour.

So, it should definitely be prepared immediately before use, and dry as possible.

It produces 1 atmosphere of gas pressure at 32°C (which figures, seeing as that's its bp). It's quite flammable, and similar to petroleum ether, it is heavier than air. (I toasted myself due to the heavier than air factor with petroleum ether a month ago -scary), so be careful with venting it hot around a source of ignition. Autoignition point is 456°C.

Thus it might be a good idea to freeze the reaction vessel to -18°C in the freezer before putting the methyl formate in it, and don't open the reaction vessel until it's fully back to room temperature.

Also it is incompatible with acids, specifically mentioning oxidising agents. HCl is not a super strong oxidiser like perchoric or nitric acid, but it does oxidise. Anyway, making the ester is very likely a fairly short process, less than an hour. It would need to be salted thoroughly with dehydrated salts to remove all the water from the HCl solution immediately it was ready to reduce the amount of reaction that took place. Might be problematic... Experiments will point the way.

Just looking around a little further, it seems that ethyl formate is a common fragrance chemical, and definitely not watched, and can be substituted for methyl formate. The only thing that puzzles me is that the mp of ethyl formate is lower than methyl formate. this may or may not have implications for the process.

Ethyl formate is about $40US for 500ml, which enough for 7 reactions as I have described in my theoretical synthesis. Which at a hopeful 90% yield is results in about 62g elfspice.

If methyl formate can be made via the method I have described, though it must be done immediately before use, it would prove a lot cheaper than that.

Revisions will be made on the synthesis to add a method of producing catalyst, as well as making methyl formate shortly.

Perhaps an ester makes a poor decarboxylation catalyst. No matter, acetone is freely available. Is there any reason to suspect that the ketone group will mess up any other part of the tryptophan other than the carboxylic acid? If there isn't, then why not just use the ketone alone? Also, somebody answer the question: does decarboxylation require a normal atmospheric pressure in the gas phase or can it get as high as (say) 4atm without significantly interfering with the decarboxylation? Does anyone know? Preliminary experiments with glutamic acid could help (just an amino that I have handy) Tyrosine would be better, would make 4-hydroxy-phenethylamine as a product. Not useful probably, but would confirm the decarboxylation worked if it came out as a freebase waxy thing that boiled somewhere between 60 and 140°. If I use this, I could do a parallel experiment using ethyl acetate made from ethanol and acetic acid with HCl catalyst. And see what happens! The N-Formyl 4-hydroxy phenethylamine would be a bit different, but I would assume it would have some characteristic which would make it identifiable.

Watch this space for experimental writeups of precursor processes.

Here's a quote from a site describing a process of removing water from slurry (peat, etc) to make it into a useful fuel:

When heated under pressure to temperature, carboxylic groups attached to the coal structure decompose to form carbon dioxide, which forces liquid water out of the pores and into the carrier medium

Which suggests that decarboxylation can occur under pressure. ?

I'm having trouble finding proof either way at this point.



  • Guest
Re: Variation on TiHKAL synth
« Reply #21 on: February 24, 2002, 05:09:00 AM »

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