TMO
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Aldehyde to nitrile
There are a few articles about using Iodine and ammonia water to do this however I cannot find any actual procedures that go into detail on the exact
conditions, amounts and yield. I was wondering if anyone had tried this out and could share some info.
Some refs. are (J. Org. Chem. 2003, 68, 1158. DOI) and
Talukdar, S.; Hsu, J.-L.; Chou, T.-C.; Fang, J.-M.. Direct transformation of aldehydes to nitriles using iodine in ammonia water. Tetrahedron Letters
(2001), 42(6), 1103-1105
If anyone could find the articles that would be great too I can only view the outlines of them 
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ziqquratu
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Here we go:
Direct Conversion of Aldehydes to Amides, Tetrazoles, and Triazines in Aqueous Media by One-Pot Tandem Reactions
Jiun-Jie Shie and Jim-Min Fang
J Org Chem, 2003, 68:1158 - 1160
Attachment: Aldehydes to amides, tetrazoles, triazines w NH3 I2.pdf (50kB)
This file has been downloaded 970 times
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ziqquratu
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And:
Direct transformation of aldehydes to nitriles using iodine in ammonia water
Sanjay Talukdar, Jue-Liang Hsu, Tzu-Chi Chou and Jim-Min Fang
Tet Lett, 2001, 42:1103-1105
Attachment: Aldehydes to nitriles w NH3 I2.pdf (59kB)
This file has been downloaded 1364 times
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TMO
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Thank you very much that was exactly what I was looking for.
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Sauron
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I'm highly skeptical of the transformation of aldehyde to nitrile with these reagents and especially in an aqueous medium
The transformation of aldoxime to nitrile (Beckmann rearrangement) accomplishes this but, in nonaqueous media.
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Nicodem
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Since this is at least the second time I see you calling the dehydration of aldoximes as "Beckmann rearrangement", it is time for a correction. The
Beckmann rearrangement is something quite different. It is a real rearrangement as opposed to your H2O elimination from the aldoxime to form a
nitrile. Its mechanism can be seen here. With aldoximes the dehydration is almost always a very major side reaction of the Beckmann rearrangement while with the appropriate reagents
it is possible to make the dehydration the main reaction.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Sauron
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See:
Beckmann Rearrangement of Oximes under Very Mild Conditions
L. De Luca, G. Giacomelli, A. Porcheddu, J. Org. Chem., 2002, 67, 6272-6274
which has been posted in References and by me in one of the threads for some time.
Feel free to write a LOC to the editors of JOC if you disagree with Dr DeLuca's use of the named-reaction Beckmann Rearrangement to encompass the
aldoxime to nitrile transformation rather than scorning it as a mere side reaction.
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Dr. Beaker
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| Quote: | Originally posted by Sauron
I'm highly skeptical of the transformation of aldehyde to nitrile with these reagents and especially in an aqueous medium
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It works. and very nicely.
http://www.sciencemadness.org/talk/viewthread.php?tid=8067&a...
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Sauron
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Fine, I'll give it a closer look.
It's of no use for my immediate oxime to nitrile project as the product is immediately destroyed by water, so the medium needs to be anhydrous.
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TMO
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Dr. Beaker it was your post that got me interested in it.  I sent you a U2U a
long time ago you just never replied.  Glad to here it works and will be testing
it soon. Those articles are very nice thank you again Ziqquratu.
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Dr. Beaker
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Glad Ziqquratu was able to give you the pdf's. I just didn't had the time, sorry.
Anyway, if you want and have the time I'll be interested to hear if you tried it on other aromatic aldehydes then the ones in the article or mine.
I'll also be glad to try answer questions about the rxn if you have any.
one thing about safty - don't use the same funnel you used to add iodine to pour the ammonia solution - NI3 will be formed on the funnel, and will
likely explode. it's not enough for real damage but still a very loud bang...I made this mistake and it was pretty frightening.
[Edited on 2-6-2007 by Dr. Beaker]
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Nicodem
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| Quote: | Originally posted by Sauron
See:
Beckmann Rearrangement of Oximes under Very Mild Conditions
L. De Luca, G. Giacomelli, A. Porcheddu, J. Org. Chem., 2002, 67, 6272-6274
which has been posted in References and by me in one of the threads for some time.
Feel free to write a LOC to the editors of JOC if you disagree with Dr DeLuca's use of the named-reaction Beckmann Rearrangement to encompass the
aldoxime to nitrile transformation rather than scorning it as a mere side reaction. |
The authors of that paper never claimed their method for aldoxime dehydration is a Beckmann rearrangement even though they speculate about the
possibility of it having a similar mechanism (a 1,2-hydride shift instead of the usual E2 mechanism). But how could it even be a rearrangement if
nothing rearranges? Anyway, all I wanted was for you to stop spreading this misinformation. I do not care if it was unintentional or not. All I do
care about is the reliability of information, a value I naively believed you had in common.
To keep on the thread's topic:
I can give another second hand confirmation that the I2/NH3 oxidation of a certain alpha,alpha-dimethylpropanal does in fact yield the corresponding
nitrile.
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TMO
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One more quick question has anyone tried using a lower concentration of ammonia? The paper stated they used 28%. I was wondering if 4% or 10% could
possibly substitute so long as it was compensated for. If no one knows I will give it a try and post back but will be a bit.
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Dr. Beaker
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I have'nt tried but as stated in the J. Org. Chem. 2003 article the intermediate is an N iodo imine and then NH3 causes it to eliminate HI to make the
C-N triple bond. If you use dilute solution of ammonia you have less NH3 and more NH4+OH-. and you need 2 equivalents of NH3 per 1 of the aldehyde...
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