gemar14
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Does triiodoethanol exist?
Hello, everyone! I've recently decided to try out some trihaloethanol esterifications just to see how quickly these esters cleave after the fact. I'm
aware that 2,2,2-trifluoro, trichloro and even tribromoethanol are all known and commercially available. However, not only have I not seen any
commercial sources of the triiodo variant, but I have also not found it mentioned in any papers anyway. Does it simply not exist at room temp?
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Boffis
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Hi gemar14,
I couldn't find anything on 2,2,2-triiodethanol but it might be possible to prepare it from iodoform and formaldehyde though the three iodine atoms on
one carbon are going to make it pretty crowded but the is a 1,1,1-triiodoethane.
The is a 1,2,2-triiodoethanol though which surprised me but on a quick search I couldn't out much about it.
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BromicAcid
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Usually simpler compounds like that have all been synthesized centuries ago. It's easy to think that perhaps there is some barrier to their
preparation if you can't find anything. After all, generally if someone made 1,1,1-tribromoethanol for the first time their next inclination would be
to try to repeat the process to make the triiodo material. Still, sometimes things like this just fall through the cracks. If think that if there
was some reason why it couldn't be synthesized (randomly underwent dehydration or the like) you'd be more likely to find information on it. But -
like others here, I couldn't find anything on it on Reaxys or just a general search of the ACS journals. So, perhaps it has just never been a
synthesis target.
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gemar14
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Yeah, that seems to be the choices I'm struggling with as well. Is it not reported just because it's not possible to make or because no one has
bothered to make it? I usually lean away from the "no one has bothered" explanation, but who knows in this case
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j_sum1
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Sounds like the prelude to one of those stories where an anatuer does it because he didn't know it couldn't be done.
Seriously though, it would be nice to have some clearer guidance.
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Boffis
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Given that ethanol undergoes the iodoform reaction I suspect you would have great difficulty in preventing the molecule from falling apart  .
I still think the best route to try would be the reaction of formaldehyde with iodoform in ethanol. The iodoform may just act as an oxidizing agent
giving formic acid and diodomethane.
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Bedlasky
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Quote: Originally posted by Boffis  | | Given that ethanol undergoes the iodoform reaction I suspect you would have great difficulty in preventing the molecule from falling apart . |
It does the same with bromine/chlorine to form bromoform/chloroform. Still trichloro/bromoethanol exist.
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gemar14
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What's even weirder is that apparently triiodoacetic acid exists both commercially and in the literature. Yet not a word about the alcohol
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Boffis
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Interestingly and coincidentally today I spotted some information on 1,1,1-tri-iodoethane or as he calls it "methyl-iodoform" in Arun Sethi's
chemistry book where it is described as a pale yellow solid, sparingly soluble in alcohol and Mp 95 C. Unfortunately there is no reference
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clearly_not_atara
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Chloral is not further oxidized by chlorine, which is why it is so easy to make. Only when alkali is added does it decompose into chloroform and
formate. So presumably triiodoacetaldehyde would behave similarly. But the problem is, the diiodoacetaldehyde might not be further oxidized due to the
carbonyl withdrawing electrons from the hydrogen. This doesn't mean that triiodoethanol doesn't exist, but it would make it harder to produce than the
trichloro or tribromo compound, since enol iodination is not available.
Possibly, the reaction of ethanol with iodine monochloride would give triiodoacetaldehyde, this later being reduced to triiodoethanol. The same trick
works for arene iodinations.
[Edited on 04-20-1969 by clearly_not_atara]
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gemar14
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| Quote: Originally posted by clearly_not_atara | Chloral is not further oxidized by chlorine, which is why it is so easy to make. Only when alkali is added does it decompose into chloroform and
formate. So presumably triiodoacetaldehyde would behave similarly. But the problem is, the diiodoacetaldehyde might not be further oxidized due to the
carbonyl withdrawing electrons from the hydrogen. This doesn't mean that triiodoethanol doesn't exist, but it would make it harder to produce than the
trichloro or tribromo compound, since enol iodination is not available.
Possibly, the reaction of ethanol with iodine monochloride would give triiodoacetaldehyde, this later being reduced to triiodoethanol. The same trick
works for arene iodinations. |
What do you feel about triiodoacetic acid to acid chloride with SOCl2, then reduction to the alcohol with borohydride?
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