10-06-04 08:06
No 534644
SWIW has just finished his first Henry condensation, used 50 g 2,5-DMBA, procedure almost exactly like Pihkal # 20. After dissolving in IPA, filtering, washing the filter cake with IPA, repeat till filtrate not dark, got aproximately 65 g of a nice, homogeneous carrot colored substance, nice color, needles seen but kind of amorphous look. Still a bit wet with IPA.
My problem, the yield is close or higher than 100 %. Obviously there are impurities and/or IPA mixed in. My question, can I input this as it is for reduction ?
According to Shulgin, what he got was of sufficient purity to input to the reduction step. I am just hoping the impurities are not going to affect the reduction yield. Of course, I am sure Shulgin got better product than I did, but am just hoping impurities might not adversely affect reduction step yield, at least not too much. I hope to have enough to distill the 2C-H ( and hopefully the 2C-B also ).
Also, what would be a typical yield for the Henry condensation would be ?
Worth re-xtalizing this from IPA ? Or use as it is OK ?
Just in case, 2,5-DMBA 98 % pure; nitro from RC fuel; ammonium acetate reagent grade.
I am still overloaded with work, but hope to find time to try to reduce this to 2C-H, maybe next week.
(Chief Bee)
10-06-04 17:31
No 534682
You need to dry the nitrostyrene to a crisp first, especially if you are going for a hydride-based reduction. Check ../rhodium /2cb.syn
The Hive - Clandestine Chemists Without Borders
(Hive Bee)
10-06-04 22:25
No 534726
Thanks Rhodium. No, I am not planning to use LAH or something like that. Will tell you what happened later. Will try to dry it, still too clumpy and wet.
(Hive Bee)
10-07-04 20:40
No 534848
After drying, now nitrostyrene looks dry, powdery, IPA smell almost totally gone, weight went down to 39.6 g. This corresponds to 62 % yield, a bit less I guess.
(Hive Bee)
10-14-04 16:07
No 535812
SWIW has reduced 19 g of the above nitrostyrene with zinc dust 5:1 by weight, with good results. Got 13.1 g of a white powdery substance, just slightly yellow, hopefully 2C-H.HCl. Will try to brominate later on. Still want to reduce the remaining nitrostyrene first.
(Newbee)
10-14-04 21:16
No 535854
Where did you substitute the LAH for?
And did you mean 5:1 Zn didn't you use Zn+MeOH.
(Hive Bee)
10-14-04 22:02
No 535859
With nitroethenes, Zn/HCl substitutes for LAH...
(it reduces both the C=C bond and the nitro group, but doesn't work with longer alkyl chains like nitropropenes)
(edit: Yes, what you did is the Leminger reduction... but Zn/NH4Cl can reduce oximes - a modification of the Zn/formic reduction posted by Lego (Post 477266 (Lego: "Reduction of oximes with zinc/ammonium formate", Novel Discourse) I just got confused as there is currently a thread in the novel discourse dealing with Zn reductions, too... (Post 535551 (pablos: "Oxime", Novel Discourse)), and besides, Zn/HCOOH also reduces nitro groups.. sorry.)
indole_amine
(Hive Bee)
10-15-04 03:45
No 535900
As far as I know, the reducing agent is Zn dust only. Look in the Rhodium site, there is one paper under 2C-B, the autor is Leminger. I used MeOH as the solvent with some HCl excess. Temperature control under 30 C only OK. Got this from The Hive, private communication.
Worst part is the work up, but OK if done correctly. I cloggeg my sep funnel with Zn(OH)2, then decided to extract with toluene + big plastic container + stirrer, worked fine.
So far looks OK, clean, I will know for sure if bromination works as expected.
(Hive Bee)
10-15-04 07:29
No 535913
BTW you could also reduce the nitrostyrene to the nitroethane with NaBH4 (that is, if you have some), and then to the phenethylamine with Zn/NH4COOH - 2 steps vs. one, but maybe with more ease (and maybe higher yields?).
Usually the results are better if two reductions are done with two different reactions; but in this case Leminger is almost perfect.
indole_amine
(Hive Bee)
10-15-04 16:20
No 535970
I have asked someone here about doing it with two reductions or one, I was advised to do it with one reduction. BTW, my yield is already 65 % ( coarse crystallization, not distilled yet ) and to beat that you would need something like 90 % followed by 75 % or so.
For instance, if you have say 0.9 * 0.7 = 0.63 it is less than 0.65.
Also, like to hear you say Leminger it is almost perfect for this reduction. I think it is very clean, no tar, final product looks like it has been gassed out.
Also, modifications to paper procedure include maximum temperature 30 C and also to add all nitrostyrene after the MeOH and HCl, then add the Zn in small portions.
I will tell you whatever happened later.
(Hive Bee)
10-15-04 23:14
No 536001
Hey, can you please post your proceedure for the reduction of the nitrostryene, swim has had aweful results when attempting it.
(Hive Bee)
10-15-04 23:42
No 536004
Keep your temperature under control at all times. Ice bath is good idea.
President of the Iraqi Chemical Weapons of Mass Destruction Development Society
(Hive Bee)
10-16-04 05:14
No 536035
Dear Amine, and others, there it is. I have not contacted the person who gave me the hints on this, but I assume he would not object. If he agrees, I will of course include his name later on. One word of caution, this still not finished, but, I have this fellow word it works, I have seen the amine on top, fishy smell, got it after the A/B, etc, looks right.
Reduction with Zinc Dust / Al ( by Wolfx )
- Setup:
- Place a 2 l BF over a stirrer, with a fitting funnel on top and
also a thermometer. Don't let the thermometer to hit the spin-
ning bar. Cool the BF with ice. During the zinc addition and
after, do not let temperature to exceed 30 C.
Reagents :
- 2,5-dimethoxynitrostyrene ( 20 g )
- Zinc dust ( 100 g )
- MeOH ( 200 ml )
- HCl 31 % ( 300 ml )
Procedure :
- Add 200 ml MeOH to the BF. Slowly add 300 ml 31 % HCl. Watch the
temperature, let it cool down to under 30 C.
- Add all of the 2,5-dimethoxynitrostyrene all at once. It should
dissolve easily, everything then a nice uniform orange color.
- Start dropping in the zinc dust in small ammounts. It will foam
a bit, but soon stops, foaming decreases. Watch the temperature
at every zinc dust addition. Don't let it go over 30 C. Should
take one hour or more.
- After addition complete, drip inside BF a small ammount of MeOH
to wash orange foamed in sides of BF. Glass will look clear now.
- Stir for a total reaction time of 7 h, including zinc addition.
At the end, the orange color is completely gone, there is a clear
watery liquid with some zinc at the bottom. Color yellow-gray,
clear, transparent.
- Filter out zinc. Should now have some 700 ml of a clear yellow
liquid, looks like white wine.
- Workup :
- Setup for distillation, distill out HCl and most of the MeOH.
- Dissolve 200 g NaOH in 600 ml water. It will heat up, let it cool
down to RT or close.
- With cooling, stirring, slowly drip in the filtrate in small
increments. Newly formed Zn(OH)2 will make solution thick milk
white. Keep stirring.
- After all filtrate added in, add some 150 ml of toluene and stir
for a few minutes. Place in fridge ( optional ) and wait one hour
or so. Now, most of the Zn(OH)2 on bottom. Carefully decant the
top water + toluene layer. Filter out any Zn(OH)2 carried over.
- Separate the toluene, it will be on top of the water layer. Wash
the toluene if you feel like.
- Now, gas it or back extract with dilute HCl and dry on low heat.
- Should have now 2C-H.HCl.
- Comments :
- This is a modification of the Leminger reduction, hints on the
reduction procedure and workup given to me as private com-
munication.
- Previous post has been edited. Changed title, added reagent ammounts, also added distilling out HCl + MeOH before dripping in NaOH. Have not tried workup whithout distilling out the HCl + MeOH first, but it should work, I think there is NaOH enough. In the original Leminger paper it is not done.
(Hive Bee)
10-16-04 08:04
No 536050
BTW you could also reduce the nitrostyrene to the nitroethane with NaBH4 (that is, if you have some), and then to the phenethylamine with Zn/NH4COOH - 2 steps vs. one, but maybe with more ease (and maybe higher yields?).
Is this from personal experience or are you theorizing? In my experience, Zn/formate reductions of nitroalkanes work but it's tricky to get good yields on a consistent basis. Other methods have been found to perform better.
(Stunning)
10-16-04 08:50
No 536053
Why don't you wanna try Al instead of all pain in the butt, you're have with other Reductians???
Original procedure: ../rhodium /nitrost
Everything works very well.
Good luck.
-who dares, wins-
(Hive Bee)
10-16-04 15:55
No 536083
The original one has been edited, but no major changes.
Added removing HCl + MeOH before dripping in NaOH solution.
Answering to Tricky, never tried the Al reduction, but this is nice and easy to do, the worst part is the Zn(OH)2 but easy to deal with. I have been told you can get 75 % yield.
(Hive Bee)
10-16-04 19:15
No 536095
Starlight:
There are threads about experiences with Zn/NH4COOH, one I remember is by SpicyBrown: it is about 4-fluoroamphetamine and has the words "full report" in its title (or at least something similar
). If you search for SBs posts, you will find it very quickly...indole_amine
(Hive Bee)
10-18-04 20:30
No 536395
I'm aware of the thread you are talking about (I've read most of the posts here over the last four or five years), but others (including very experienced bees) have experienced inconsistent yields using the Zn/NH4COOH method.
10-19-04 14:55
(Rated as: redundant)
(Hive Bee)
10-19-04 15:23
No 536589
The nitro reduction using Zn/HCOOH or Zn/NH4COOH is indeed and unofortunateley very inconsistent.
Has anyone tried to freebase the lemminger post reaction with aq NH3? This might improve the ease of workup.
Hippler