Conjugate acid of DMAP

Watch this thread
waldonator
Badges: 0
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
Report Thread starter 6 years ago
#1
I know that DMAP is a very strong base because the conjugate acid would be stabilized by delocalisation of the +ive charge...but which site is there protonation-the N of the -NMe2 group or the N in the heterocycle? It is a derivative of pyridine but I don't know how to work this out! Thanks
0
reply
charco
Badges: 18
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report 6 years ago
#2
(Original post by waldonator)
I know that DMAP is a very strong base because the conjugate acid would be stabilized by delocalisation of the +ive charge...but which site is there protonation-the N of the -NMe2 group or the N in the heterocycle? It is a derivative of pyridine but I don't know how to work this out! Thanks
Both nitrogen atoms will be protonated and each will have a pKb value depending on which is protonated most easily.

There are pros and cons for the amine. It is sterically hindered by the surrounding bulky groups, but the +I effect of two methyl groups boosts the charge density of the lone pair.

The pyridine nitrogen lone pair is easily available and the positive charge is easily conjugated around the ring...

My guess is the ring nitrogen.
0
reply
waldonator
Badges: 0
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
Report Thread starter 6 years ago
#3
(Original post by charco)
Both nitrogen atoms will be protonated and each will have a pKb value depending on which is protonated most easily.

There are pros and cons for the amine. It is sterically hindered by the surrounding bulky groups, but the +I effect of two methyl groups boosts the charge density of the lone pair.

The pyridine nitrogen lone pair is easily available and the positive charge is easily conjugated around the ring...

My guess is the ring nitrogen.
So much to consider! Thanks a lot
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Has advance information helped during your exams?

Yes (68)
66.02%
No (26)
25.24%
I didn't use it to prepare (9)
8.74%

Watched Threads

View All