The Vespiary

The Hive => Methods Discourse => Topic started by: Natrix on November 11, 2001, 05:24:00 PM

Title: DOC
Post by: Natrix on November 11, 2001, 05:24:00 PM
D. Ehlers, J. Schäning - Synthese von DOC (2,5-Dimethoxy-4-chloramphetamin):

http://www.gtfch.org/tk/tk68_2/Ehlers.pdf (http://www.gtfch.org/tk/tk68_2/Ehlers.pdf)

Title: Re: DOC
Post by: PrimoPyro on November 11, 2001, 05:32:00 PM
I assume the reaction of the amine with acetic anhydride, forming the acetamide, is done as an amine protecting function for the aromatic nitration step?

Is this the reasoning behind this step?

                                                 PrimoPyro
Vivent Longtemps la Ruche! STRIKE For President!
Title: Re: DOC
Post by: Rhodium on November 11, 2001, 09:42:00 PM
Yes, it is a protection group. It also protects the nitrogen from being oxidized by the nitrous acid in the diazotization step. Good find, Natrix!
Title: Re: DOC
Post by: Aurelius on November 11, 2001, 10:06:00 PM
Rhodium, could you add that to your page (in english?)
Title: Re: DOC
Post by: Rhodium on November 11, 2001, 11:26:00 PM
Yes, I'll translate it when I have the time.
Title: Re: DOC
Post by: Osmium on November 12, 2001, 12:39:00 AM
Well, it's interesting but not very much suited as a production guide. An 8 step synth with sometimes dramatically shitty yields.
But it is the first chemistry ref. I have seen which cited Pihkal!  ;D
Title: Re: DOC
Post by: yellium on November 12, 2001, 12:43:00 AM
It's a shitty synth, but direct chlorination isn't perfect either. The issues with di/trichlorination are for real. And using NCS isn't that much of an improvement if you want to obtain reasonably pure 2C-C/DOC.

Title: Re: DOC
Post by: Rhodium on November 12, 2001, 02:01:00 AM
I believe the protection/deprotecting scheme can be omitted, if the product is carefully puified afterwards, and that a low enough pH is used in the diazotizing step to minimize any reaction of the aliphatic amine with the nitrous acid (aliphatic amines are less reactive at low pH's, but not aromatic amines).
Title: Re: DOC
Post by: moo on November 12, 2001, 10:51:00 PM
If it is so, that even a LAH reduction can be done without damaging the aromatic halogen, then what is wrong with adding the halogen to the benzaldehyde and then proceeding as one wishes. For example, the use of Ca(OCl)2 will only monochlorinate. I would like to know, because it seems there is some reason behind all this I haven't been able to find out. Oh, and there are countries where 2,5-DMA is illegal but DOC is not.
understanding is everything
Title: Re: DOC
Post by: Rhodium on November 13, 2001, 09:06:00 AM
LAH would probably rip off the chlorine substituent if it was present on the nitrostyrene. Either another reducing agent like AlH3 should be used, or the chlorine has to be put there afterwards.

The document is now translated and placed on my page:

https://www.thevespiary.org/rhodium/Rhodium/chemistry/doc.synth.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/doc.synth.html)

(please point out any errors that I may have made)