The key difference between azomethines and ketimines is that the azomethines are a type of secondary aldimine which contains the carbon atom in the functional group attached to one hydrocarbyl group and a hydrogen atom whereas the ketimines are a type of imines which contains the carbon atom of the functional group attached to two hydrocarbyl groups.
An imine can be either a functional group or a chemical compound consisting of a carbon-nitrogen double bond (C=N bond). Since the maximum number of neutral bonds a nitrogen atom can make is 3, the nitrogen atom is bonded to a hydrogen atom or an organic group other than this C=N bond. We can relate imines to ketones and aldehydes by replacing the oxygen atom in the aldehyde or ketone with the NR group. Therefore, there are two types of imines; they are the aldimines and ketimines. In those, the aldimines contain an R group and a hydrogen atom bonded to the carbon atom of the N=C group while the ketimine contains two hydrocarbyl groups attached to this carbon atom.
CONTENTS
1. Overview and Key Difference
2. What are Azomethines
3. What are Ketimines
4. Similarities Between Azomethines and Ketimines
5. Side by Side Comparison – Azomethines vs Ketimines in Tabular Form
6. Summary
What are Azomethines?
Azomethines are secondary aldimines. These are imine compounds containing one hydrocarbyl group and one hydrogen group attached to the carbon atom of the N=C bond and a hydrocarbyl group attached to the nitrogen atom.
Figure 01: General Structure of a Secondary Aldimine
What are Ketimines?
Ketimines are a type of imines where two hydrocarbyl groups are attached to the carbon atom of the N=C bond. There are two types of ketimines as primary ketimines and secondary ketimines.
Figure 02: General Structure of a Primary Ketimine
Figure 03: General Structure of a Secondary Ketimine
The primary ketimines contain a hydrogen atom attached to the nitrogen atom whereas the secondary ketimines contain a hydrocarbyl group attached to the nitrogen atom.
What are the Similarities Between Azomethines and Ketimines?
- Azomethines and ketimines are two types of imines.
- And both contain hydrocarbyl groups.
What is the Difference Between Azomethines and Ketimines?
Azomethines are secondary aldimines while ketimines are a type of imines where two hydrocarbyl groups are attached to the carbon atom of the N=C bond. Therefore, the key difference between azomethines and ketimines is their structure. Azomethines are a type of secondary aldimine that contains a carbon atom in the functional group attached to one hydrocarbyl group and a hydrogen atom whereas ketimines are a type of imines that contains a carbon atom of the functional group attached to two hydrocarbyl groups. Moreover, azomethine is a chemical analogue of aldehyde while the ketimine is a chemical analogue of ketone.
The following infographic summarizes the differences between azomethines and ketimines in tabular form.
Summary – Azomethines vs Ketimines
An imine can be either a functional group or a chemical compound consisting of a carbon-nitrogen double bond (C=N bond). Azomethines and ketimines are two types of imines. However, the key difference between azomethines and ketimines is that the azomethines are a type of secondary aldimine which contains the carbon atom in the functional group attached to one hydrocarbyl group and a hydrogen atom whereas the ketimines are a type of imines which contains the carbon atom of the functional group attached to two hydrocarbyl groups.
Reference:
1. “Ketimine.” ScienceDirect Topics, Available here.
2. Collins, Sonya. “What Is Ketamine? How It Works and Helps Severe Depression.” WebMD, WebMD, 27 Feb. 2018, Available here.