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Author: Subject: L-PAC cyanamide and enantioselectivity
roamingnome
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[*] posted on 22-6-2012 at 19:51
L-PAC cyanamide and enantioselectivity


Even back in 2009 a member "Turd" did mention in a trashed thread about L-Pac that LPAC would be a interesting way toward
4-methyl-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine aka 4-MAR

and certainly you must agree that using L-PAC for anything other then ephedrine would be interesting at some level.

Back during 2009 I was chasing links and ideas along this theme as well. I read Korean papers reacting Urea with acyloin. I read papers
from The Bulletin of the Chemical Society of Japan. In the end lots of good ideas but no published reactions regarding
alpha-hydroxyketones to 2-amino-2-oxazolines.



So now in 2012 i re-ran some searches regarding this subject mater and came, i think, as close as you can get. Well anything is possible,
but a one pot from L-Pac to oxazoline remains elusive.

http://www.google.com/patents/US3052688

[img]<a href="http://www.google.com/patents?id=he5lAAAAEBAJ&zoom=4&pg=PA2&ci=569%2C874%2C389%2C348&source=bookclip"><img src="http://www.google.com/patents?id=he5lAAAAEBAJ&pg=PA2&img=1&zoom=4&hl=en&sig=ACfU3U3ybgBznZYL6dbXsUpmViQtlzMrxQ&ci=569%2C8 74%2C389%2C348&edge=0"/></a>[/img]



the savvy minded chemist will see that that in the following example the authors at least produce a interesting compound from L-PAC
with cyanamide, but it is not the oxazoline, but has a extra double bond. geometry and isomers fill my cortex......

I question what this compound would be good for? Or knowledge of its toxicity etc....

If someone were to isolate this compound it seems it could be hydrogenated selectively...

Catalytic asymmetric hydrogenation of N-Boc-imidazoles and oxazoles.
Kuwano R, Kameyama N, Ikeda R.
Source

Department of Chemistry, Graduate School of Sciences, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan. rkuwano@chem.kyushu-univ.jp
Abstract

Substituted imidazoles and oxazoles were respectively hydrogenated into the corresponding chiral imidazolines and oxazolines (up to 99% ee). The highly enantioselective hydrogenation was achieved by using the chiral ruthenium catalyst, which is generated from Ru(η(3)-methallyl)(2)(cod) and a trans-chelating chiral bisphosphine ligand, PhTRAP. This is the first successful catalytic asymmetric reduction of 5-membered aromatic rings containing two or more heteroatoms.

© 2011 American Chemical Society



This is were i wish i was a better chemist to plot out the potential isomers of the reaction..
Also, are there more strait forward ways of potentially hydrogenating this to the oxazoline.

Im not holding my breath because the forum is more concerned with whats on EBAY but i still needed to put this out...

thankyou and godspeed with your investigations


[Edited on 23-6-2012 by roamingnome]
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francis
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[*] posted on 24-6-2012 at 19:58


Quote: Originally posted by roamingnome  

If someone were to isolate this compound it seems it could be hydrogenated selectively...

Catalytic asymmetric hydrogenation of N-Boc-imidazoles and oxazoles.
Kuwano R, Kameyama N, Ikeda R.
Source

Department of Chemistry, Graduate School of Sciences, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan. rkuwano@chem.kyushu-univ.jp
Abstract

Substituted imidazoles and oxazoles were respectively hydrogenated into the corresponding chiral imidazolines and oxazolines (up to 99% ee). The highly enantioselective hydrogenation was achieved by using the chiral ruthenium catalyst, which is generated from Ru(η(3)-methallyl)(2)(cod) and a trans-chelating chiral bisphosphine ligand, PhTRAP. This is the first successful catalytic asymmetric reduction of 5-membered aromatic rings containing two or more heteroatoms.

© 2011 American Chemical Society


This is were i wish i was a better chemist to plot out the potential isomers of the reaction..
Also, are there more strait forward ways of potentially hydrogenating this to the oxazoline.

Im not holding my breath because the forum is more concerned with whats on EBAY but i still needed to put this out...

thankyou and godspeed with your investigations


[Edited on 23-6-2012 by roamingnome]


The oxazoles in the paper you cited were 4 or 5 substituted 2-phenyloxazoles.

The 5-substituted oxazole was selectively hydrogenated to form the 5R enantiomer, and the 4-substituted was hydrogenated to form the 4R enantiomer.

2-amino-4-methyl-5-phenyloxazole is trisubstituted - and the Ph is in the 5 position, rather than the 2 position (as in the paper cited).

So does this work for trisubstituted oxazoles, with a 2-NH3 instead of a 2-Ph? Will the catalyst work to allow selective hydrogenation to form the 4R,5R compound?

IF the hydrogenation worked with the 2-amino-4-methyl-5-phenylsubstituted oxazole - you would get the 4R,5R diastereomer.

But since this is rank speculation, to find out, you will have to attempt this asymmetric synthesis yourself, ensuring to abide by all local laws and regulations.
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chemrox
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[*] posted on 30-6-2012 at 01:12


There are a number of patents referenced in the rhodium pemoline article which discuss related oxazolines. http://www.erowid.org/archive/rhodium/chemistry/pemoline.htm... E.g. pemoline can be made with guanidine and mandelic acid. Methylaminorex from norephedrine and cyanogen halide. There was a thread on aminorex: http://www.sciencemadness.org/talk/viewthread.php?tid=8693. The oxazolines are interesting and fun reactions for the wary experimenter. Most of them should be considered nootropics. I'm feeling the need for nootropics lately so if you start playing around with them keep me in mind. For those without fume hoods remember the funnel/aspirator substitute and don't count too much on it completely carrying the evolved cyanide compounds.

[Edited on 30-6-2012 by chemrox]




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[*] posted on 9-7-2012 at 21:06


Quote:
Back during 2009 I was chasing links and ideas along this theme as well[...]

Heheh...I remember this.... Maybe I'll finally find a use for the somewhat unreasonable amounts of Ca cyanamide I prepped after some of our brain storming...
Thanks for the article.




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Nicodem
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12-7-2012 at 03:07

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