[Altered State]

Hi guys.
I'm starting to learn organic chemistry and I've bumped into this NMR, and I'm really sick of trying to solve it. The formula is C5H12O
Is there anything wrong or it's me that I don't see it?

[Borek]

9 protons without any coupling is a dead give-away.

[Altered State]

9 protons without any coupling is a dead give-away.

Yes, I've got that part:

······CH3
·······l
CH3-C-
·······l
······CH3

But I don't know how to continue, it doesn't make any sense to me :S

Since there is no any proton coupling in the whole molecule, I can't figure this out...

I tried:


······CH3
·······l
CH3-C-CH2-CHO
·······l
······CH3


or

······CH3
·······l
CH3-C-CH2OH
·······l
······CH3

But there is still coupling between 2 protons anyway..

[Borek]

See what is left of the formula.

I must admit I have no idea why the shift for a single proton is what it is, which can mean I am completely wrong. We will need to wait for someone more wise in the ways of science... I mean, organic chemistry

[Altered State]

See what is left of the formula.

I must admit I have no idea why the shift for a single proton is what it is, which can mean I am completely wrong. We will need to wait for someone more wise in the ways of science... I mean, organic chemistry

I see what is left in the formula... But I still don't see the way it can be wrote without any coupling, and I've bee trying for about 1 hour.

[Altered State]

I've just found this:

http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/cre_frame_disp.cgi?sdbsno=4708

So, that way, isn't there coupling between alcohol proton and CH2 protons? Why?
If there is, I think there is not another option 

[Borek]

So, that way, isn't there coupling between alcohol proton and CH2 protons? Why?

Why should it be? These protons are two atoms apart.

[Babcock_Hall]

Hydroxyl protons don't couple when they exchange rapidly.  My experience has been that the rate of exchange depends upon the solvent.  Do we know what the NMR solvent was?  I did not see it.

[Altered State]

So, that way, isn't there coupling between alcohol proton and CH2 protons? Why?

Why should it be? These protons are two atoms apart.

Well, because the OH proton is just three bonds beyond from the CH2 protons...

But it seems that it doesn't matter in this case in which we have heteroatoms like hydroxyl...

[Altered State]

Hydroxyl protons don't couple when they exchange rapidly.  My experience has been that the rate of exchange depends upon the solvent.

So should I take this like an exception for the "4 bonds beyond" rule (sorry, I'm Spanish, my English isn't so good) to determine if there is coupling or not?

[Borek]

Ah, OK, I don't know what I was thinking about. Apparently I don't know how to count to three.

Yes, hydroxyl protons can be an exception.

[Altered State]

Ah, OK, I don't know what I was thinking about. Apparently I don't know how to count to three.

Yes, hydroxyl protons can be an exception.

OK, thank you both very much, I've just learnt that there is so many exceptions in NMR, and I don't have to overtrust any rule in organic chemistry. Also, I solved this exercise after 2 hours... 

It was a great experience for my first time posting here.

See you!