Chordate
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Preparation of nitrobutane
I'm trying to keep costs down on a little side project, and sigma wants 200 bucks to send me some 1-nitrobutane. I have 1-chlorobutane laying around
n-butylamine as well.
Currently I have two proposed routes, one using Chlorobutane and sodium nitrite in DMF. I have a paper somewhere around here which suggests using
urea as a scavenger of side products. This reaction has the advantage of being almost free, but the disadvantage of needing to be babysat all day.
Anyway, a history search reveals quite a few people have played around with trying to get a nitroethane synth up and running, but does anyone have any
insight into how to tighten up the Sn2 nitration, or any adaptations that need to be made when working with the longer chain alkyl chloride?
The other option is of course oxidation of the butylamine, but peracids are out, and I don't think permanganate will work, (theres some references to
it being used but only with amines connected to a tertiary carbon).
Thats what i'm working on, and any suggestions or advice would be much appreciated.
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DJF90
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How about alkylation of a lower chain nitro compound?
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peach
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This will be the third popper related post in about as many days, but some poppers are butyl nitrite if that would be any help in terms of oxidising
your chain through to the nitrate.
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UnintentionalChaos
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Quote: Originally posted by peach  | | This will be the third popper related post in about as many days, but some poppers are butyl nitrite if that would be any help in terms of oxidising
your chain through to the nitrate. |
They said nitrobutane, not butyl nitrate. The former can a C-N bond, the latter does not.
The suggestion of alkylating a lower nitro compound is interesting. You'd have to use stoichiometric strong base at low temps I suppose, but appending
n-halopropane to nitromethane seems like a good way to go.
Alternately, do longer chain alpha-haloacids react with NaNO2 a la orgsyn for nitromethane? Hell-Volhard-Zelinsky on valeric acid would furnish the
alpha-haloacid needed.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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Nicodem
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Chordate, I would tend to think 1-chlorobutane is of no practical use for the SN2 substitution with NaNO2. Do you have any reference for this
synthesis? I think it is not reactive enough to be of any use and is also too hard electrophile for a good N-alkylation selectivity. It might work by
using AgNO2 though, but it would be more reasonable to just make 1-iodobutane from n-butanol and perform the synthesis as per literature.
I think n-butylamine can be oxidized to 1-nitrobutane with dimethyldioxirane, possibly even made in situ via the usual Oxone based methodology. There
was an article posted on the forum about DMDO oxidation of primary amines.
You mention peracids, but what is the reference for the peracids being used for such a reaction? I think only pertrifluoroacetic acid was ever
reported of being able of such transformation and even that I believe was only for t-alkyl primary amines (except perhaps for the N-oxidation of
anilines?).
| Quote: Originally posted by UnintentionalChaos | | The suggestion of alkylating a lower nitro compound is interesting. You'd have to use stoichiometric strong base at low temps I suppose, but appending
n-halopropane to nitromethane seems like a good way to go. |
Do you have any reference for that?
Generally nitronates that are not additionally stabilized, such as the nitromethane derived nitronate, get O-alkylated rather than C-alkylated
(exceptions are substitutions via SRN1). A dianion can be made from nitroalkanes (e.g., alpha lithiated nitronate) and this can be monoalkylated under
undesirable conditions (in HMPA!). There is an Angewandte article about it, posted somewhere on the forum, but obviously this is of no use for the
original poster here. Additionally stabilized nitronates, like the ethyl nitroacetate derived one, can be C-alkylated with good selectivity.
| Quote: | | Alternately, do longer chain alpha-haloacids react with NaNO2 a la orgsyn for nitromethane? |
alpha-Halopropanoic acid does so in low yields. There is at least one reference in some thread somewhere. The intermediate oxiranones are very
reactive electrophiles and easily alkylate the nitrite anion, though any substitution on the 3 position lowers their reactivity.
…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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UnintentionalChaos
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| Quote: Originally posted by Nicodem |
| Quote: Originally posted by UnintentionalChaos | | The suggestion of alkylating a lower nitro compound is interesting. You'd have to use stoichiometric strong base at low temps I suppose, but appending
n-halopropane to nitromethane seems like a good way to go. |
Do you have any reference for that?
Generally nitronates that are not additionally stabilized, such as the nitromethane derived nitronate, get O-alkylated rather than C-alkylated
(exceptions are substitutions via SRN1). A dianion can be made from nitroalkanes (e.g., alpha lithiated nitronate) and this can be monoalkylated under
undesirable conditions (in HMPA!). There is an Angewandte article about it, posted somewhere on the forum, but obviously this is of no use for the
original poster here. Additionally stabilized nitronates, like the ethyl nitroacetate derived one, can be C-alkylated with good selectivity.
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No, I was speculating based on the malonic ester synthesis, but I would appear to be wrong.
Perhaps a nitroalkene (henry reaction/nitroaldol product) can be selectively reduced to the nitroalkane.
http://www.erowid.org/archive/rhodium/chemistry/nitroalkene2...
http://www.erowid.org/archive/rhodium/chemistry/nitroalkene2...
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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Chordate
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My bad @Nicodem! By peracid I meant peroxyacid. I was referring to the use of mCPBA in this case, but it'd likely just give me a mess of the amine
oxide.
Having never done this particular Sn2 reaction I wasn't sure if the chlorine would be poor of a leaving group or the resultant nitro compound too good
a substrate. Thanks for the tip.
The DMDO method seems like it'd be great if I didn't already have the sodium nitrite, as oxone is cheap (even otc!) and easy. As it stands it seems my
cheapest route is going to be just buying some iodobutane and doing Sn2 in DMF.
A second question arises: would it be worth it to convert the sodium nitrite to silver nitrite before proceeding?
[Edited on 24-2-2011 by Chordate]
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Ebao-lu
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I wonder if oxidation of oximes to nitroalkanes is appicable for N-alkylhydroxylamines as well, but for me it seems to be applicable. If it is, then
you can try to make a N-butylhydroxylamine from butylchloride and excess hydroxylamine http://books.google.com/books?id=XKP-mFbCs_0C&pg=PA119&a...
Or you can oxidize butanol to butanal (or Kornblum oxidation of butylchloride with DMSO), then make oxime out of that, then treat it with oxone
(posted by Kinetic)
| Quote: |
When searching for articles on the oxidation of oximes to nitroalkanes yesterday I found a very useful paper.
In Synthetic Communications, 28(24), 4531-4535 (1998), oximes are oxidised to nitroalkanes in good yield using only oxone in aqueous
acetone-acetonitrile at pH 7.5. Primary, secondary and benzylic oximes all give nitroalkanes in good (generally 60-70%) yield. The closest substrate
to acetaldehyde oxime is the oxime of hexanal, giving 1-nitrohexane in 70% yield. |
or by some other method that were discussed here http://www.sciencemadness.org/talk/viewthread.php?tid=909
Also take into consideration this method http://www.organic-chemistry.org/abstracts/literature/262.sh...
[Edited on 25-2-2011 by Ebao-lu]
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Chordate
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So I was checking the 'ol reagent bench for to make sure my ducks were in a row before getting wet, and I stumbled across a jar of sodium iodide.
That chlorobutane chlorine atom isn't a great leaving group, but it should yield to iodine's vigor, and the product should already be slighly favored
just owing to the solubility difference. So I'm not even going to bother with ordering iodobutane. I'm just going to attempt to one-pot the formation
of nitrobutane from chlorobutane using NaI as a catalyst to allow the weaker NaNO<sub>2</sub> to displace chlorine.
Its not pretty, but it doesn't require me to buy anything. Hooray.
Letcha know how it goes in a few weeks.
[Edited on 7-3-2011 by Chordate]
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