question_answer

Which one of the following has the most nucleophilic nitrogen?

A)             

B)  

C)  

D)  

Correct Answer: A

Solution :

Nucleophiles are the species which have excess of electrons. Among the given species, the lone pair of nitrogen of pyrrole is involved in delocalisation of the ring, thus, are not available for donation. In aniline, the tone pair is involved in conjugation with the n electrons of the ring while in pyridine, these are relatively free for donation. Thus, nitrogen of pyridine  is most nucleophilic. (phenyl and \[-COC{{H}_{3}}\] both are electron withdrawing groups, thus decreases the nucleophilicity of nitrogen).