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Author: Subject: AlHg On different Nitrostyrenes
BobHawson
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[*] posted on 22-12-2008 at 11:43
AlHg On different Nitrostyrenes


In the procedure below, could 3,4,5-trimethoxy-beta-nitrostyrene be substituted for 2,5-dimethoxynitrostyrene and yield the correponding phenethylamine?

Or would it polymerize? Or would there be some other problematic side reactions?

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http://www.erowid.org/archive/rhodium/chemistry/2cb.synthesi...

Nitrostyrene reduction by Al/Hg.

Recently I was about to reduce 2,5-dimethoxynitrostyrene to the amine 2C-H with Al/Hg and acetic acid. I anticipated a yield of about 50-60% but I got only 35%. Yields are not good, but Shulgin reports 40% for 2C-B and 50% for 2C-H with LAH, so might be interesting to avoid buy / use LAH.

Proportions used:

1 g 2,5-Dimethoxynitrostyrene
10 ml Acetic acid
15 ml 96% Ethanol
5 ml Water
50 mg HgCl2
2 g Aluminum foil
The reaction must be carried at about 60øC, otherwise all of the starting nitrostyrene won't be dissolved. Some tips are:

Make a solution of everything but the Al, then add the foil, cut to oneinch squares at a rate enough to keep the temp around 60øC, and add until the orange colour disappear. About the double weight of nitro will be enough, maybe less.
Filter off the Al sludge, wash it with alcohol, then basify the solution with 25% NaOH. Filter again to remove the crystallized sodium acetate, and wash the filter cake with water.
Remove the solvent under vacuum, dissolve the residue in dilute H2SO4, and wash with 3x20 ml CH2Cl2. Basify with 25% NaOH and extract the solution with 3x25 ml CH2Cl2. Dry the pooled extracts over MgSO4, remove the solvent under vacuum, dissolve the residue in anhydrous ether, and saturate the solution with anhydrous HCl gas to precipitate pure 2C-H hydrochloride. To recover the 2C-H freebase, distill the residue above under vacuum instead.
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BobHawson
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appetsbud
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[*] posted on 22-12-2008 at 13:12


I'm not too versed in the way of aluminum amalgam reductions, but i don't see any reason chemically that it would cause any polymerization. The only significant difference between the two i see is the extra methoxy group, and that doesn't appear to pose much threat to the reaction, do you have any reason to believe that it would?

i think your main problem would be low yields, and nasty toxic side products.

also, i'm fairly sure this kind of discussion will be frowned upon here, especially as you could have figured the answer out yourself with a little bit of reading.

[Edited on 22-12-2008 by appetsbud]
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BobHawson
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[*] posted on 22-12-2008 at 15:13


Quote:
Originally posted by appetsbud The only significant difference between the two i see is the extra methoxy group, and that doesn't appear to pose much threat to the reaction, do you have any reason to believe that it would?

i think your main problem would be low yields, and nasty toxic side products.

also, i'm fairly sure this kind of discussion will be frowned upon here, especially as you could have figured the answer out yourself with a little bit of reading.

[Edited on 22-12-2008 by appetsbud]


I don't have any reason to think it would either, but thought I'd ask to be sure.

What do you mean by low yields? Low as in 5%? 2? Do you consider 35% low? What makes you think it would have "low" yields?

Also, what kind of nasty toxic side products?

Where might I read about this reaction using 3,4,5-trimethoxy-beta-nitrostyrene?




BobHawson
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[*] posted on 22-12-2008 at 16:29


Bob,

It can be tricky to judge sometimes, but this does not appear to be appropriate for sciencemadness. I suggest trying wetdreams instead.




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