budullewraagh
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Nitriles from Aldehydes?
I came up with this today, but it may already be patented. Nonetheless, here it is:
Start with aldehyde, react with hydrazine via imine mechanism. Add a pinch of pure acid (as close to 100% sulfuric as possible) to this in a very
non-nucleophilic solvent (di-isopropylamine, for example) and heat. Chances are, the H+ will add at the SP^3 nitrogen, which is the most basic. This
will draw electron density from the SP^2 nitrogen's lone pair, which will cause the C=N to be more polarized at the N, which will make the C-H very
acidic. The di-isopropylamine then deprotonates the C-H, causing the lone pair to go to form a triple bond with the adjacent N, resulting in an NH3
leaving group, which does well for pH balancing. The best part is that there are no nucleophiles to break the nitrile.
Any other protonation place will yield a reversible reaction.
So, what do you think? Has this been done before? Does it work?
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Dr. Beaker
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I don't know if your suggestion might work, but I synthesized for my research 2-furanitrile from 2-furaldehyde by adding iodine to the reraction
mixture of the aldehyde and ammonia. the mechanism (I think it's oxidation of the imine by I2) was not stated in the article from which I addopted
this methode but it worked great.
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stoichiometric_steve
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i think what you propose is also accomplished using (NH2)2 and SOCl2, but i'd have to look that up.
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transformer
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| Quote: | Originally posted by Dr. Beaker
I don't know if your suggestion might work, but I synthesized for my research 2-furanitrile from 2-furaldehyde by adding iodine to the reraction
mixture of the aldehyde and ammonia. the mechanism (I think it's oxidation of the imine by I2) was not stated in the article from which I addopted
this methode but it worked great. |
Would you bee willing to share your writeup of this procedure or beable to provide more reaction details on your method?
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Epopteia
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a relevant paper
Here is a paper describing the procedure. Remember, if one does this wrong, on a large scale you can form NH3.NI3 which is of course dangerous.
Attachment: aldehydes2amides.pdf (50kB)
This file has been downloaded 909 times
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Dr. Beaker
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Epopteia gave an article of the same author, Fang. the actual procedure of R-CN from R-CHO is givven in this article:
Fang, J.-M. Tetrahedron Lett. 2001, 42, 1103.
I followed the general procedure described there, and used CaO on the crude nitrile (to remove water and acids) and Vacuum distilation to recieve a
practically clean product (verified by 1H NMR).
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Dr. Beaker
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I'm giving here the procedure I pased from my thesis work.
It is written in Hebrew and I translated it in an online translator. the translation is not perfect but I think you can understand the main things.
have fun.
2 Furanitrile was prepared by means of reaction between 2 Furaldehyde and between iodine and amonia similarly to the procedure 105.
Iodine ( 97.32 mmol, 24.7gr ) added within mixing to the solution of 2 furaldehyde ( 88.47mmol, 8.5gr ) and ammonia water ( 900 milliliters of
concentration 25% ) and thf ( 90 milliliters ) that was prepared in 2 liter flask. After about – 5 minutes of mixing the dark solution converted to
the gray, and was left to mixing During about an hour. To the mixture of the reaction added 500 milliliters of a solution of na2s2o3 in the
concentration 5%, and she divides for three equal parts, each washed with three portions of Ether ( 300 milliliters ). the organic fractions were
integrated, and dried by na2so4removal of the solvent under reduced pressure brought to the receipt of the gross nitrile as oil in the yellow shade.
Cleaning of the gross product becomes by means of his drying with cao during about an hour and distillation under reduced pressure. the clean nitrile
( 6.5gr, 79% utility ) collects by the exile of Shlnk as fat yellowish and preserve under an ambience of argon.
1H NMR (300 MHz, Toluene d8): δ = 6.58 (d, 3J = 0.8Hz, 1H, furyl), 6.15 (d, 3J = 1.9Hz, 1H, furyl), 5.58 (dd, 3J = 1.9Hz, 0.8Hz, 1H, furyl). 13C
NMR (300 MHz, Toluene d8): δ = 147.3 (C-O), 126.3 (O-C-CN), 122.0, 111.4 (furyl, CN).
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Sandmeyer
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Ballini, Roberto; Fiorini, Dennis; Palmieri, Alessandro; Syn. Lett.; 12; 2003; 1841 - 1843.
decanal ---NH2OH*HCl/NaI/Acetonitrile/Heat/85 min---> decanenitrile
Yield is 94%
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