Topscore 3 ORGO question

[Orgodox]

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Hey so the question is number 84 in topscore test 3 Orgo section. I got a 25 in OChem (by far highest of all the subjects) but I really dont get number 84.

They asked which amine is most basic?

They narrow it down to NH2 on a 6 member ring with 1) methyl groups on both sides of it, or F on both adjacent carbons or just NH2 on the ring

They say that methyl one has 2 electron donating methyl groups and the florine one has 2 withdrawing groups so the most basic one is the one donating electrons. I know this concept but it doesnt apply here

When I read it I was like HUHHH!!! They are not interacting with the NH2 group or even the carbon attached to the NH2 group? There are no pi electrons to move the charge around any hyperconjugative donation of the methyl which is the reason it electron donating doesnt work that far away! Anyone have an idea?

Maybe its just a poor question for trying to teach the point that electron donating groups in the right position can make compound more basic.

 

[osimsDDS]

well you have an anniline with 2 methyl groups para correct, thats way more basic then 2 Flourine groups para to the anniline groups which are electron withdrawing (moderately)....

Doesnt the rule say that if you have electron donating (NH2) and electron donating next to it (CH3) it will make it more basic...

Putting an electron withdrawing group next to the NH2 group will make it less basic because i like to think of the Flourine atom taking away the electrons (withdrawing) of NH2 while CH3 gives electrons (donates) to NH2 making it more basic...

 

[Orgodox]

Sorry its not aniline its just a cyclohexane with an NH2 and ch3 to its left and right. No double bonds so no ineraction

 

[osimsDDS]

o btw orgodox, sharks signed blake, boyle, and lukowich....08/09 is our year!!!! haha

 

[osimsDDS]

Sorry its not aniline its just a cyclohexane with an NH2 and ch3 to its left and right. No double bonds so no ineraction

oh yea i see what your saying now, i thought it was anniline with benzene ring...what is the rule if its not a benzene ring??? do you think maybe the had a typo and accidently didnt draw it as a benzene even tho they prob meant it to be...

 

[Orgodox]

well you have an anniline with 2 methyl groups para correct, thats way more basic then 2 Flourine groups para to the anniline groups which are electron withdrawing (moderately)....

Doesnt the rule say that if you have electron donating (NH2) and electron donating next to it (CH3) it will make it more basic...

Putting an electron withdrawing group next to the NH2 group will make it less basic because i like to think of the Flourine atom taking away the electrons (withdrawing) of NH2 while CH3 gives electrons (donates) to NH2 making it more basic...

Exactly I agree that would be the caze if there were double bonds in the ring but without them the NH2 is isolated and they have no effect at all

 

[Orgodox]

o btw orgodox, sharks signed blake, boyle, and lukowich....08/09 is our year!!!! haha

I KNOW ITS CRAZY!!! If its not this year theres gana be some big time changes more than just a head coach like this past summer. Im surprised they had the patience to go at it again by just firing Wilson but these are great moves, looks promising but were still defending champs and picked up Hossa!

I dont think its a mistake though because they say something about aliphatic amines are more basic than with aromatic groups attached which I agree because the lone pair is tied up in resonance. So now I think they are mixing up differernt concepts
1)More basic if not aromatic
2) more basic if the AROMATIC ring has electron donating group

It shouldnt have any effect if noncojugated ring has electron donating group

 

[DRHOYA]

1.) Pretty cool for your sharks.

2.) So let me get this straight. Based on the rules if it was a real anniline (benzene ring included) with methyl groups.......they are both e-donating and would increase basicity. And if the other ring had a halide instead of methyl, it would be less basic b/c of the slight e-withdrawing/deactivating property of the halides. But since the question only had a hexane ring, then the "ring" properties are out the window, and you are just looking at the NH2's with either methyl or halide. So now you can just say that comparing the two, the NH2 is more acidic thus less basic just based on comparing it alone to a halide??? Or am I completely wrong? What was the correct answer?