Imidazole and Pyrazole. Where is the Basic Site

Both imidazole and pyrazole are moderately strong bases. 

Electrostatic potential map for imidazole shows negatively-charged regions (in red) as likely protonation sites. 

Draw a Lewis strueture for each molecule that shows the location of all nonbonding electrons. Examine electrostatic potential maps for both imidazole and pyrazole. Predict which is the more basic nitrogen in each molecule. What kind of orbital contains this nitrogen s nonbonding electrons What kind of orbital contains the other nitrogen s nonbonding electrons  

Which nitrogen in each molecule is more basic Compare energies of the alternative conjugate acids (Nprotonated imidazole, NH protonated imidazole, N protonated pyrazole and NH protonated pyrazole). Which compound, imidazole or pyrazole, is more basic Compare the energies of protonation (leading to the favored conjugate acid in each case). Rationalize your result. 

Histidine, one of the 20 natural amino acids, contains an imidazole ring. 

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