Atenolol is a $\mathbf{\text{β}}$(beta) blocker, a drug used to treat high blood pressure. Which of the indicated N-H bonds is more acidic? Explain your reasoning.

Atenolol is regarded as a medication employed to cure blood pressure and chest pain related to the heart.

This medication is consumed via the mouth, or it can be provided to the vein by injection.

The Lewis structures of the conjugate bases have to be compared with each other when each hydrogen is removed to understand which of the N-H bonds is highly acidic. The conjugate base that is stable can make the proton acidic.

Let us consider the structure given below:

Removal of the proton from atenolol

In this structure, the resonance stabilizes the negative charge on N. So, this conjugate base is regarded as more stable and is generated by the removal of the highly acidic hydrogen. Hence this proton is considered to be more acidic.

Let us consider the removal of another proton from the molecule atenolol.

Removal of another proton from atenolol

In this structure, no resonance stabilization is created from the weak acid. Hence, this can be considered as the less acidic proton.