Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Secondary amine to alkane?
RebeccaOlson
Harmless
*




Posts: 22
Registered: 9-3-2017
Member Is Offline

Mood: No Mood

[*] posted on 20-5-2017 at 22:37
Secondary amine to alkane?


Hey guys, I was wondering if there is any simple reaction to change a secondary amine to an alkane, for example N-Methylaniline to Ethylbenzene. Thank you :)

View user's profile View All Posts By User
Assured Fish
Hazard to Others
***




Posts: 319
Registered: 31-8-2015
Location: Noo Z Land
Member Is Offline

Mood: Misanthropic

[*] posted on 20-5-2017 at 23:42


Simple reaction? Hell no
You could however demethylate to aniline and then diazatize the amine using NaNO2 and HCl at 0*C and then react that with the appropriate halide salt to get halobenzene and then from there you could react that with haloethane and sodium metal to get ethylbenzene. The whole idea in general is kinda impractical, it would be far easier to merely start from aniline.
http://www.prepchem.com/synthesis-of-chlorobenzene/
http://www.prepchem.com/synthesis-of-ethylbenzene/
The major issue is in the demethylation of aniline, i cannot find much info behond doing so biochemically but to be honest unless you are working from a much larger molecule i would recommend scrapping the idea of working from N-methylaniline and just start at aniline.




Preparation-of-ethylbenzene.png - 45kB

View user's profile View All Posts By User
Melgar
Anti-Spam Agent
*****




Posts: 2004
Registered: 23-2-2010
Location: Connecticut
Member Is Offline

Mood: Estrified

[*] posted on 21-5-2017 at 20:27


But there IS a simple reaction! You just need some thermal neutrons. Oh yeah, and your product is going to be super radioactive, and eventually decay back into what you started with, so don't even THINK of using that ethylbenzene to make drugs.
View user's profile View All Posts By User
Assured Fish
Hazard to Others
***




Posts: 319
Registered: 31-8-2015
Location: Noo Z Land
Member Is Offline

Mood: Misanthropic

[*] posted on 21-5-2017 at 21:41


:o
Bravo Melgar, bravo.
View user's profile View All Posts By User
laserlisa
Hazard to Self
**




Posts: 52
Registered: 5-2-2016
Member Is Offline

Mood: No Mood

[*] posted on 22-5-2017 at 03:02


That Wurtz-Fittig looks really cool. ( https://en.wikipedia.org/wiki/Wurtz%E2%80%93Fittig_reaction )
I would love to be able to make alkylbenzens without having to mess with dangerous organoilithium compounds.

But it seems surprisingly hard to find references of it being used in modern chemistry. Any obvious reasons for this? Harsh conditions and low yields?

View user's profile View All Posts By User
Alice
Hazard to Others
***




Posts: 111
Registered: 11-5-2015
Member Is Offline

Mood: No Mood

[*] posted on 22-5-2017 at 03:59


@laserlisa,
here is a review including the Wurtz-Fittig reaction:

http://pubs.acs.org/doi/full/10.1021/om058054a

The reaction gives usually good yields if the cheaper halogen compound is used in excess. I think its usefulness is limited by the low functional group compatibility. The sodio arenes exhibit a higher reactivity than their lithio counteparts.

[Edited on 23-5-2017 by Alice]
View user's profile View All Posts By User
Melgar
Anti-Spam Agent
*****




Posts: 2004
Registered: 23-2-2010
Location: Connecticut
Member Is Offline

Mood: Estrified

[*] posted on 22-5-2017 at 07:10


Quote: Originally posted by Assured Fish  
:o
Bravo Melgar, bravo.

Oh, you're too kind! Though in all seriousness, that was not all that different from how they were first able to synthesize perbromates. Theory seemed to indicate that they could exist, it's just that nobody could figure out how to make them. Somehow they were successful with the nuclear option before they'd tried using fluorine though; maybe they just had all these extra nuclear isotopes and needed to do something with them before they decayed away?

If you actually want ethylbenzene, hydrogenation of styrene (available OTC as "resin thinner" from boating stores) is probably the most straightforward way to go. You can even depolymerize polystyrene if you're desperate enough, though it's not pretty.
View user's profile View All Posts By User
Nicodem
Super Moderator
Thread Moved
22-5-2017 at 09:34

  Go To Top