[lancenti]

Hi everyone!

I was hoping if I could get confirmation or objections to my ordering of the base strength of the three nitrogens in histamine. Here's a link to make it easier: http://en.wikipedia.org/wiki/Histamine

Ok, the Aromatic nitrogen with a hydrogen seems to be the least basic to me since its lone pair is delocalized into the aromatic ring so it's not readily available for donation.

I'm thinking that the aliphatic amine is more basic than the previous one but less basic than the last nitrogen, which is in the aromatic ring but has its lone pair in p-orbitals. I think this because the aromatic ring nitrogen can delocalize the negative charge over the whole ring but the aliphatic cannot.

I'm told that its the other way around but can't seem to find any trouble with my reasoning. =(

[stewie griffin]

Ok, the Aromatic nitrogen with a hydrogen seems to be the least basic to me since its lone pair is delocalized into the aromatic ring so it's not readily available for donation.

Sounds reasonable. I think you're really close to the answer (if I understand you correctly then yes you've picked the most basic nitrogen). I would phrase your reasoning in a slightly different way, but you can probably figure it out with a small hint: how about drawing some resonance structures with the aromatic ring and see if something ends up with some negative charge character on it...
More negative charge something has = more basic that something is...

[lancenti]

Thank you for the *delete me*

[lancenti]

... that's odd, I don't remember typing "*delete me*" >.>

Thank you for the assistance!