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

Printable Version  
Author: Subject: Betaine methylation
morsagh
Hazard to Others
***




Posts: 187
Registered: 20-2-2014
Member Is Offline

Mood: No Mood

[*] posted on 8-1-2015 at 14:41
Betaine methylation


Can be betaine used for methylation an amino group (and in which conditions)?
View user's profile View All Posts By User
AvBaeyer
National Hazard
****




Posts: 651
Registered: 25-2-2014
Location: CA
Member Is Offline

Mood: No Mood

[*] posted on 8-1-2015 at 19:10


The simple answer is no.

AvB
View user's profile View All Posts By User
Yugen
Harmless
*




Posts: 23
Registered: 20-12-2014
Member Is Offline

Mood: No Mood

[*] posted on 8-1-2015 at 22:06


Quote: Originally posted by AvBaeyer  
The simple answer is no.

AvB

Actually it might work... people use tetramethylammonium to methylated phenols (using basic conditions & microwave heating), so why not amines with a different quaternary ammonium ion? I doubt you are gonna have much control over the types of products you get (probably all tertiary amines because the more alkyl groups an amine gets, the easier if becomes to add another alkyl group).


But who knows until it's actually tried right? Try adapting this paper's procedure.

http://www.sciencedirect.com/science/article/pii/S0040402008...
View user's profile View All Posts By User
Haber
Harmless
*




Posts: 40
Registered: 13-4-2014
Location: Thule
Member Is Offline

Mood: No Mood

[*] posted on 9-1-2015 at 06:50


Quote: Originally posted by Yugen  
... the more alkyl groups an amine gets, the easier if becomes to add another alkyl group).

...

Are you sure about this? Could you explain why this is the case?

I would have thought of the opposite, mainly because of sterical hindrance, but also wouldn't the alkyl groups reduce the nitrogens nucleophility?
View user's profile View All Posts By User
Dr.Bob
International Hazard
*****




Posts: 2750
Registered: 26-1-2011
Location: USA - NC
Member Is Offline

Mood: No Mood

[*] posted on 9-1-2015 at 08:29


For small alkyl groups, each extra methyl on a nitrogen makes it more nucleophilic in general. That is why it is hard to make methylamine or dimethylamine, as each of those is methylated faster than ammonia. If you add isopropyl groups, for instance, it become more sterically hindered, which is why diisoproylethylamine (DIEA, Hunig's base) is used as a mostly non-reactive base, but even that can react with some alkylating agents under harsh conditions.
View user's profile View All Posts By User
Nicodem
Super Moderator
Thread Moved
9-1-2015 at 12:33

  Go To Top