aromaticity

MS 912 - Benzyl Position and Aromaticity Submitted by Matt on August 6, 2011.

Textbook and Chapter: Carey and Giuliano 8th Ed. (2010), Chapter 11

Keywords: aromaticity, benzylic position, heteroaromatic compounds

Description: Goes over benzene, aromaticity, and the benzyl position (1 carbon away from benzene).
Lots of aromatic resonance practice.

Total Problems: 5

Problem # 584

Imidazole (shown below) has two nitrogen atoms, N-1 and N-3. Which nitrogen is more basic?

To answer this problem, draw the product after each nitrogen protonates, and compare their stabilities. Explain your reasoning.

Problem # 583

Pyrrole is an example of a heteroaromatic compound: it contains a heteroatom (atom that is not carbon or hydrogen, such as N, O, S, etc.), and is aromatic.

Because pyrrole is aromatic, we should be able to draw many resonance forms- usually as many resonance forms as sides (in this case, five sides, so five resonane forms).

Draw all resonance forms for pyrrole. (I've started you off.)

Problem # 582
 

Rationalize the follwing pKa values. Explain your answer in terms of the stabilites of the conjugates bases of each acid.

Note: the lower the pKa, the stronger the acid.