Question

Explain why pyrimidine is less basic than pyridine

Short answer

The electron-withdrawing inductive effect of extra nitrogen of pyrimidine removes electron density from the lone pair of nitrogen making the pyrimidine less basic than pyridine.

Step-by-step solution

Inductive effect

Polarization of a bond due to the electron-withdrawing or donating effect of adjacent atoms or groups is known as an inductive effect.

Explanation for less basic nature of pyrimidine

• Electron-donor groups enhance the basic nature of amines whereas electron-withdrawing groups decrease the basicity of amines.

• The electron-withdrawing inductive effect of extra nitrogen of pyrimidine removes electron density from the lone pair of nitrogen making the pyrimidine less basic than pyridine

Basicity order

Hence, pyrimidine is less basic than pyridine.