Organic Chemistry: Acid Base Question

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xjoohn

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Hello can any one answer this question for me?

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ACS Organic Chemistry

Thanks.

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The answer should be B if i'm not mistaken. The sp2 hybridized nitrogen is going to be more basic because it is in a position to donate it's lone pair and pick up an electrophile, the lone pair is perpendicular to the π system, making it less likely to donate into making the ring aromatic. The sp3 hybridized nitrogen is in a position to donate it's pair into making the imidazole ring aromatic, and thus will do so, and its lone pair will not be available to an electrophile.
 
I don't know the answer but I can say that all atoms are SP2 and this is an aromatic ring.
 
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I don't know the answer but I can say that all atoms are SP2 and this is an aromatic ring.

If you made me pick I choose A. There is resonance of the aromatic Nitrogen atoms so the positive charge of the protonated form could spread the charge and be more stable.

Yea, I guess they are all sp2 hybridized, but I do know that the lone pair of the NH nitrogen is actually part of the aromaticity, but the other N contributes a single electron into the ring system, but the lone pair sticks out perpendicular and is available for bonding to an electrophile. I still think B is the correct answer haha, but I could be completely off base.
 
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Cawolf,

I thought resonance in ring = make it more stable . Therefore it's a weak conjugated base or strong acid. is that the wrong logic to think???

I'd pick B also
 
I honestly don't know.

All I know is that it is aromatic. I am just starting Organic 2 right now. I hope the OP has a solution to provide.

All the posts I have read have sound logic - seem good to me.
 
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