QuestionOrganic / basicity of amines
The relative order of basicity of the following amines is:
- (a) 1 > 2 > 3 > 4
- (b) 4 > 1 > 2 > 3
- (c) 4 > 3 > 2 > 1
- (d) 2 >3 > 1 > 4
Answer: (b) 4 > 1 > 2 > 3
4 Et₃N: aliphatic, sp³ lone pair free → most basic. 1: two ortho CH₃ twist NMe₂ out of the ring plane (steric inhibition of resonance) → lone pair not delocalised → more basic than aniline. 2 aniline > 3 p-nitroaniline (−R of NO₂). 4 > 1 > 2 > 3 → (b).