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karlos³
International Hazard
Posts: 1520
Registered: 10-1-2011
Location: yes!
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Mood: oxazolidinic 8)
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Well, zed, I think it is because of the quality of the Pd/C.
I bought it from a well known auction site, without an original package, without any guarantee, just because it was cheap.
As I am a bit short of money, and have too many projects running around, I haven´t tried another substrate with this catalyst yet.
Because I am not sure if it is worth it, maybe another substrate will do fine, but maybe the catalyst is bad and it will be frustrating.
I wish I had prepared it myself... just a bit NaBH4, active charcoal and PdCl2. Then I would have at least known it would work.
But for the nitriles, I recently found out that mandelonitrile is dirt-cheap, and can even be reduced with Na in alcohol, preferably n-BuOH.
So if everything else is not satisfying, I will buy like 25ml of mandelonitrile and work with this.
Sodium alkoxides are very cheap and good reducing agents and this route looks also very appealing to me.
I like working with sodium as reducing agent, that is a very neat one if it can be used.
Also cheap and easy to prepare and work-up afterwards.
So many options, so little time. But everyone here helped me a great deal with it, so I´ll have a lot to do and try out, and hopefully a lot of
personal experience to add here soon!
With good results I hope(crossing my fingers/pressing my thumb/any gesture else to hope for luck).
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Chemi Pharma
Hazard to Others
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Karlos, you'd better try Nickel Boride made in situ reacting not expensive NaBH4 with NiCl2.6H2O in methanol to reduce 2-nitrophenylethanol. See the
paper below:
Attachment: Reduction Of Aliphatic Nitro Compounds To Amines Using NaBH4_NiCl2 and Ultrasound.pdf (157kB)
This file has been downloaded 413 times
Attachment: sodium borohydride-nicl2.pdf (399kB)
This file has been downloaded 426 times
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karlos³
International Hazard
Posts: 1520
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I did it now using the epoxide of styrene and with succinimide, the yield was as expected lousy, but it was very pure then after cleavage. A second
run using the epoxide and hexamine was much better, but took a longer time and the solvents were more expensive.
But thank you for your suggestion, it will be worthwhile when I am doing it with the para-fluoro substituted nitroalcohol.
Sadly, when I tried to prepare more epoxide and wanted to pour out the styrene into a beaker, nothing came out... I shook the can, nothing happened...
no sound of liquid in there... banged on the can, still nothing :-D
So now I have a can full of glass-like polymer, it happened very fast, suprisingly fast even!
Maybe the stabilisator was out of capacity to inhibit any polymerisation? (The monostyrene was like 2-3 years old)
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Organikum
resurrected
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Location: Europe
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Mood: frustrated
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Two Efficient Enantioselective Syntheses of 2-Amino-1-phenylethanol.
Tanielyan, S. K., Marin, N., Alvez, G., & Augustine, R. L.
Organic Process Research & Development, 10(5), 893–898. (2006).
doi:10.1021/op060122x
The article discloses also a superior way to hydrolyze the succinimido alcohol (compared to the German article where the this compound is derived from
styrene oxide and succinimide) with excellent yields.
The reaction of succinimide and styrene oxide can for sure also be optimized and together with the better hydrolysis it seems the method of choice for
Phenylethanolamine.
Also in the article: Resolution of the stereoisomeres can be done by di-O-toluoyltartaric acid or dehydroabietic acid.
[Edited on 24-2-2023 by Organikum]
Attachment: Two Efficient Enantioselective Syntheses of 2-Amino-1-phenylethanol.pdf (121kB)
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