Which of the following is the correct IUPAC name for a compound with a cyclohexyl group attached to the nitrogen atom of $3-\mathrm{hexanamine}$?

• A. $3-\mathrm{cyclohexylhexan}-1-\mathrm{amine}$
• B. $N_{}$-cyclohexyl-$3-\mathrm{hexanamine}$
• C. $N_{}$-hexylcyclohexanamine
• D. $3-\mathrm{hexylcyclohexanamine}$

Answer: (B)

Verified step by step guidance

1. Identify the parent structure: The base compound is 3-hexanamine, which means a six-carbon chain (hexane) with an amino group (-NH2) attached to carbon 1, and a substituent at carbon 3.
2. Determine the substituent attached to the nitrogen atom: The problem states there is a cyclohexyl group attached to the nitrogen, not to the carbon chain. This means the cyclohexyl group is an N-substituent.
3. Apply IUPAC nomenclature rules for amines with N-substituents: When a substituent is attached to the nitrogen atom of an amine, it is indicated by the prefix 'N-' followed by the substituent name, then the name of the parent amine.
4. Write the correct name by placing the N-substituent first: The name should be formatted as N-cyclohexyl-3-hexanamine, indicating the cyclohexyl group is on the nitrogen and the amino group is on carbon 1 of the hexane chain with a substituent at carbon 3.
5. Avoid incorrect naming that implies the cyclohexyl group is attached to the carbon chain: Names like 3-cyclohexylhexan-1-amine or 3-hexylcyclohexanamine suggest the cyclohexyl group is on the carbon chain, which is not the case here.