PROBLEM 25.37 - Organic Chemistry

Question

Question: Varenicline (trade name Chantix) is a drug used to help smokers quit their habit. 

(a) Which N atom in varenicline is most basic? Explain your choice. 

(b) What product is formed when varenicline is treated with HCl?

Step-by-Step Solution

Answer

Answer

 

a. hybridized nitrogen atom is more basic due to less % s-character.

b. The product is formed when varenicline is treated with HCl - an ammonium chloride salt. 

Basicity of amines

In general, for hybridized nitrogen atom, more the % s-character, the closer the electron is to the nucleus and more available for donation making it a weak base.

More basic nitrogen atom in varenicline

(a) The structure of varenicline is shown as:

Types of N atom

The compound varenicline has two types of nitrogen atoms. 

 

One is sp²  hybridized nitrogen and another is  sp³ hybridized nitrogen.

 

sp² has % s-character than  sp³  . Therefore, sp³  hybridized nitrogen atom is more basic.

(b) Amine react with hydrochloric acid to form an ammonium chloride salt. 

Reaction with HCl