a. For the compound above, identify each nitrogen as either a primary, secondary, tertiary, quaternary, or aromatic amine.

Question

Chemical structure of an amine compound with labeled nitrogen atoms for classification as primary, secondary, or tertiary.

Accepted Answer

All right. Hi everyone. So this question says to consider the structure shown below, determine the amine classification of each nitrogen atom as either heterocyclic aromatic primary secondary tertiary or quaternary. And here we have four different answer choices, proposing different designations for all four nitrogen atoms. Now recall first and foremost, right, that a means can be classified as either primary secondary tertiary or ordinary depending on how many carbon atoms are attached to nitrogen directly. Right? An am mean is primary if it has only one carbon atom connecting to nitrogen, it is secondary if there are two carbon atoms attaching to nitrogen, its tertiary, if there are three carbon atoms attached to nitrogen and it's ordinary, if it has four carbon atoms attached to nitrogen. Now a total of four carbon atoms attached to a nitrogen would actually give nitrogen a positive chart, right? So ordinary amines are referred to as instead as ordinary ammonium ions because nitrogen would have a positive charge. However, an amine is considered to be heterocyclic aromatic if you have an aromatic molecule, specifically an aromatic ring with nitrogen embedded in the ring structure. So in this case, right, recall that there are many common recognizable heterocyclic aromatic amines. But in the case where it is not recognizable, then you would have to check the aromatic requirements to see if the hetero cycle is in fact aromatic. But if we start off with the first nitrogen atom, for example, the nitrogen atom is embedded within a ring that looks a lot like benzine. And so benzene is in fact aromatic. So this compound is in fact an a heterocyclic aromatic molecule because it is purity right. So it is very similar to benzene in structure, except you do have a nitrogen atom embedded within the ring. So the first nitrogen or the first amine would be heterocyclic aromatic. And so the second Amin towards the top of the structure has one nitrogen atom with a positive charge and four carbon atoms attached to it directly. So because of this right, the second nitrogen is ordinary and so this functional group would be a ordinary ammonium ion. So slightly to the left of the second nitrogen atom is the third. And I can see that the third nitrogen atom has two carbon atoms on either side of it. Therefore, two carbon atoms connecting to that nitrogen directly. So therefore the third amine or the third nitrogen would be classified as secondary. Whereas the fourth one is slightly tricky, right? Because notice how only two groups are listed on either side of the nitrogen for the fourth nitrogen here. But notice how our methyl group rch three is enclosed in parentheses with a subscript of two. Now, this means that there are actually two methyl groups attached to our nitrogen in addition to the other Ocu group to the left of nitrogen itself. This means there are a total of three carbons attached to the fourth nitrogen, meaning that it is tertiary. And so if I scroll down to consider my answer choices, the correct answer is going to be option B in the multiple choice because the first nitrogen atom is heterocyclic aromatic, where the first amine is, the second is ordinary, the third is secondary and the fourth is tertiary. So with that being said, thank you so very much for watching and I hope you found this helpful.

a. For the compound above, identify each nitrogen as either a primary, secondary, tertiary, quaternary, or aromatic amine.

Verified video answer for a similar problem:

Key Concepts

Amine Classification

Structural Representation

Chemical Properties of Amines