Author Topic: n-propylamine - how to get it? (Read 241 times)

no1uno · « **on:** June 19, 2010, 10:38:10 PM »

I'm looking through some old papers (Benkeser mainly) and have noticed that which I ignored once before, that n-propylamine can be used instead of ethylenediamine with lithium for reduction using the Benkeser/Birch Reduction.

Now, we know ethylamine can be used too, but it has a fairly low BP (16.6'C), whereas n-propylamine has a BP of ~48'C (which is much better for our purposes, a normal condenser should handle that).

How to get at it? Can people see if they can find any references to the decarboxylation of gamma-aminobutyric acid (GABA) to give n-propylamine (or the same with B-alanine to give ethylamine).

I'm on it myself, but maybe several hands might lighten the load?

Anyway, good luck

Sedit · « **Reply #1 on:** June 20, 2010, 03:43:59 AM »

Longer chain amines show a marked reduced ability to solvate the Lithium as can be shown in various literature posted across many boards. You will more then likely have to dissolve some NH₃ into the propylamine to achive the desired effect which would be childs play at this point.

We have a thread here devoted to amino acid decarboxylation perhaps the best place to start. It sounds like a wounderful idea so let me know how it turns out and PM me soon please.

Vesp · « **Reply #2 on:** June 20, 2010, 10:00:49 PM »

If N-propanol is not difficult to get, the obvious could be done by turning it into the amine by first halogenation via HBr and then reaction with ammonia. N-Propanol is not easy to get, however, I believe it has been said to be in a cleaner of some sort.

Vanadium · « **Reply #3 on:** June 21, 2010, 05:52:07 AM »

Propylene glycol can be dehydrated to propionaldehyde which can in turn be reductively aminated to propylamine. Coincidentally, I found a ref for doing the latter step in a very easy and OTC manner the other day:

Quote

Amongst the reduction methods used in organic chemistry, there are many
methods using Zn. The zinc is used, either in metal form, or associated
with other metal in the form of a couple: Zn-amalgam (BER 46: 1837 ('13),
Zn-Cu, Zn-Pd and Zn-Pt are described in the literature. The couple Zn-Ni
has not received attention by chemists.

The Zn-Ni couple is only active in the presence of base: ammonia or
hydroxide ions. We've used ammonia as base in most cases.

Preparation of the couple: One can obtain this easily by treating a
ammoniacal solution of a nickel salt, e.g. the sulfate, with powdered zinc.
The nickel is reduced and releases hydrogen, while the zinc is transformed
into the oxide, which dissolve slowly in the ammoniacal solution. In some
cases it's necessary to remove the ionised nickel, either because it'll
form an insoluble complex with the substance to be reduced, or because one
wants to replace the ammonia with sodium/potassium hydroxide.

We've realised the hydrogenation of several functional groups in this work:

Reductive amination of ketones
------------------------------

If a commercial solution of ammonia is used (with added alcohol to
solubilise the ketone), one obtains a moderate yield of the corresponding
amine. Cyclohexanone gives a 60-70% yield of cyclohexylamine.
Methylbenzylketone is transformed in the same way to phenylisopropylamine.

http://www.erowid.org/archive/rhodium/chemistry/znhg.alhg.reductions.txt

Vesp · « **Reply #4 on:** June 21, 2010, 06:37:16 AM »

Quote

Propylene glycol can be dehydrated to propionaldehyde..

Could we see more on that? I thought it produced Propylene oxide, instead of propionaldehyde.

If butanioic acid can be obtain more easily, making the amide, and performing a hoffman on it could be of use here.

SOMA · « **Reply #5 on:** June 21, 2010, 09:29:08 PM »

Under pinacol rearrangment conditions propylene glycol should give propionaldehyde, there is a prep in org. synth. in witch they dehydrate glycerine to acrolein with KHSO4, acrolein is to propionaldehyde what allyl alcohol is to n-propanol.

Beter prepare butyramide with a butyrate esther and aqueos ammonia because butyric acid stinks like hell, vomit like, althogh the amide might smell even worse.

Vesp · « **Reply #6 on:** June 21, 2010, 09:36:45 PM »

http://householdproducts.nlm.nih.gov/index.htm

Searching for butyl acetate, it seems to be found in a few products as high as 30%

On OrgSyn I did not find any synthesis of propionaldehyde from propylene glycol - perhaps someone can provide a link?
I am a bit skeptical that the analogues reaction from glycerol to acrolein will produce propionaldehyde from propylene glycol.

Quote

One of them, Charles Friedel, believed the reaction product to be the epoxide tetramethylethylene oxide [4] in analogy with reactions of ethylene glycol. Finally Butlerov in 1873 came up with the correct structures after he independently synthesised the compound trimethylacetic acid which Friedel had obtained earlier by oxidizing with a dichromate. [5]

-- wiki

Vanadium · « **Reply #7 on:** June 22, 2010, 04:37:19 AM »

Quote from: Vesp on June 21, 2010, 06:37:16 AM

Quote
Propylene glycol can be dehydrated to propionaldehyde..

Could we see more on that? I thought it produced Propylene oxide, instead of propionaldehyde.

If butanioic acid can be obtain more easily, making the amide, and performing a hoffman on it could be of use here.

Personally I'm more interested in that OTC reductive amination (

) but here's a paper that you don't need access to (info is in the first paragraph) that backs up my claim:

The 9th result from a google search for "propylene glycol dehydration":

Quote

Propylene glycol dehydrates and rearranges in concetrated sulfuric acid to a mixture of allyl alcohol and the enolic form of propionaldehyde.

http://pubs.acs.org/doi/abs/10.1021/ac60128a032

The difference in BP for allyl alcohol (a very useful side product

and propionaldehyde is ~50 degrees. I see no reason why bisulfite couldn't be used instead of sulfuric acid for reasons of cost; the acid is but a catalyst.

EDIT 1: Dimerization seems possible, though. :/ Probably not that big of a problem.
EDIT 2: Ooooh, the dimer is a popular fragrance product. Can you say retro-aldol?
EDIT 3: http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0015
The OrgSyn link, courtesy of SOMA from that other thread.

Obviously the same precautions against polymerization don't need to be taken.

Vesp · « **Reply #8 on:** June 22, 2010, 09:31:35 PM »

Oh excellent, thanks for those links - Allyl Alcohol is indeed a very useful chemical as well.

no1uno · « **Reply #9 on:** June 29, 2010, 07:18:43 PM »

Sodium Dithionite is supposedly the tool of choice in the specific reduction of double=bonds and also for the reduction of carbonyls to alcohols, thus allyl alcohol would give n-propanol with dithionite (which contrary to popular opinion is OTC), like most things, it just takes some finding.

The n-propanol could then be converted to the n-propyl halide (Lucas reagent or the easier version dissolving the wet salt in strong HCl and gassing the piss out of it), from there the amine is rather simple (Separation of the primary, secondary, ternary & Quaternary amines shouldn't pose major problems - the difference in weight should make for easy separation via distillation).

There is also at least one patent (attached) which I don't have the equipment presently to play with, but which beats the Rhodium/Lyceum preparation of sodium hydrosulfite/dithionite hands down. It involves reacting Aluminium metal with 2M-13M HCl, till H2 is given off, then reacting the mix with SO2 to form Aluminium Hydrosulfite/dithionite. Addition of NaOH to this will give sodium aluminate and sodium hydrosulfite, which beats shit out of using zinc powder or sodium formate for mine.

Tsathoggua · « **Reply #10 on:** July 03, 2010, 08:04:12 PM »

I would be inclined to avoid acrolein like the plague, it is apparently prone to explosive polymerization byproduct formation, and god damn, it is an effective lachrymator to boot, I made some when I was just a nipper via dehydration of glycerine with bisulfate.

Lets just say the result was it being poured down the drain quick style, and running like hell, cursing the air blue. its a lot worse than chloroacetone, this was on a test tube scale, any large scale up would alert nosy neighbours if it wasn't scrubbed efficiently.

Vanadium · « **Reply #11 on:** July 04, 2010, 06:00:09 AM »

^Then it's a good thing nobody was as stupid as to recommend getting propylamine from acrolein.

Anyway, as a half-on-topic for the process OP has in mind, since 1,2 diaminoethane works very well in such reductions, perhaps 1,3-diaminopropane could be made from propylene glycol as well. Birch reductions aren't my specialty but I see no obvious reason why this molecule couldn't work in such a reaction.

EDIT: Besides isomerization to acetaldehyde if you use an acidic reagent.

b6baddawg · « **Reply #12 on:** July 04, 2010, 07:20:14 AM »

not wishing to debunk the thread, but would phenylpropylamine otc be sufficient for where you wish to go? youd have to separate it from a glucose solution thats all.
then its a jump either way to a coupla nasties.

are source products ok to discuss?

Vesp · « **Reply #13 on:** July 04, 2010, 07:36:23 AM »

Quote

are source products ok to discuss?

RULES

b6baddawg · « **Reply #14 on:** July 04, 2010, 08:40:42 AM »

oki read the rules vesp,

so to say its available as a vetinery product ( without naming the brand/s) to tighten the bladder muscle for treatment of incontinence in bitches, cheaply,otc. would suffice.

i would assume you could work backwards if one wished to do so to n-propylamine from there. or forwards. depends what u want it for? meth? ice?

Author Topic: n-propylamine - how to get it? (Read 241 times)

no1uno

n-propylamine - how to get it?

Sedit

Re: n-propylamine - how to get it?

Vesp

Re: n-propylamine - how to get it?

Vanadium

Re: n-propylamine - how to get it?

Vesp

Re: n-propylamine - how to get it?

SOMA

Re: n-propylamine - how to get it?

Vesp

Re: n-propylamine - how to get it?

Vanadium

Re: n-propylamine - how to get it?

Vesp

Re: n-propylamine - how to get it?

no1uno

Re: n-propylamine - how to get it?

Tsathoggua

Re: n-propylamine - how to get it?

Vanadium

Re: n-propylamine - how to get it?

b6baddawg

Re: n-propylamine - how to get it?

Vesp

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b6baddawg

Re: n-propylamine - how to get it?