[r1]

1) can anyone tell how oxygen atoms will decrease/increase the nucleophilicty of NH2 group in 3,4-(Methylenedioxy)aniline?
2) How tert-butyl is increasing the nucleophilicity of amine group in 4-tert-Butylaniline?


Thanks very much

[Dan]

Please read Forum Rules[/u], you must show that you have attempted the question.

The factors involved are inductive effects and mesomeric effects causing relative electron richness in comparison to unsubstituted aniline. Read about these effects in the acid/base chapter of any organic chemistry textbook and see what you can come up with. We can guide you from there.

[r1]

please verify this-

1)resonance stabilization (charge delocalization) due to oxygen atom in 3,4-(Methylenedioxy)aniline is decreasing the nucleophilicity (thus basicity) of the amine.

2) +I effect is increasing the nucleophilicity of NH2 in 4-tert-Butylaniline

[Dan]

please verify this-

1)resonance stabilization (charge delocalization) due to oxygen atom in 3,4-(Methylenedioxy)aniline is decreasing the nucleophilicity (thus basicity) of the amine.

No, explain your reasoning. Are oxygen atoms electron donating or electron withdrawing through resonance?

[r1]

oxygen atoms are donating electrons in resonance

[sjb]

oxygen atoms are donating electrons in resonance

OK, so what happens when you push the electrons on the oxygen attached at the 3-position? Does this increase or decrease the basicity? What about when you push those attached to the 4-position?

[r1]

-  position 3 involving e- donating resonance stabilization is increasing the basicity of the amine.

-at 4th position there will be no conjugation.