Pls answer this: 

Dear Student,

Dear Student,

For compound 1, the two methyl groups contribute to +I effect on the nitrogen of the amine group. However, the nitrogen is attached to a benzene ring which has two electron withdrawing nitro groups at the meta position. This leads to delocalization of the lone pair on the nitrogen atom. Thus, compound 1 has very low basic strength.

For compound 2, the nitrogen is bonded to a cyclohexane group which provides +I effect. Thus, this compound has high basic strength.

For compound 3, the nitrogen which is double bonded should have a higher basicity. However, the nitrogen atoms attached to the double bonded carbon lead to -I effect, thus decreasing the overall charge density on the carbon. Also, double bond conjugation is possible in the system , which can lead to decrease in the basic strength of the amine. Thus, this compound is more basic than (I) but less basic than (II).

For compound 4, basicity is similar to that of (II) because of +I effect of the alkyl groups. However, the nucleophilicity of the compound is a little less because of steric hindrance by the alkyl groups. Thus, it is more basic than (III) but less basic than (II).

Thus, the correct order of basic strength is (a).

(II) > (IV) > (III) > (I)

Hope it helps.


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