4-dimethylaminopyridine (DMAP; below) is an extremely useful molecule in organic chemistry. One professor here at OSU often comments to graduate students when theirreaction isn't working just to sprinkle a little DMAP into their reaction. Which nitrogen atom of DMAP is most nucleophilic? Use drawingsanda minimumamount of wordsto support your answer.

Nitrogen A would be more nucleophilicity (figure 1.)

Explanation:

In the DMAP molecule we will have 2 nitrogens label as "nitrogen A" and "nitrogen B". For nitrogen B we will have more steric hindrance due to the 2 methyls groups and the benzene ring. What will hinder the attack from this nitrogen (nitrogen B) to an electrophile. On the contrary, the attack of nitrogen A could easily occur.