Question

Draw the structural formula for a compound with the given molecular formula. (a) \(\mathrm{A} 2^{\circ}\) arylamine, \(\mathrm{C}_{7} \mathrm{H}_{9} \mathrm{~N}\) (b) \(\mathrm{A} 3^{\circ}\) arylamine, \(\mathrm{C}_{8} \mathrm{H}_{11} \mathrm{~N}\) (c) \(\mathrm{A} \mathrm{}^{\circ}\) aliphatic amine, \(\mathrm{C}_{7} \mathrm{H}_{9} \mathrm{~N}\) (d) A chiral \(1^{\circ}\) amine, \(\mathrm{C}_{4} \mathrm{H}_{11} \mathrm{~N}\) (e) \(\mathrm{A} \mathrm{} 3^{\circ}\) heterocyclic amine, \(\mathrm{C}_{6} \mathrm{H}_{11} \mathrm{~N}\) (f) A trisubstituted \(1^{\circ}\) arylamine, \(\mathrm{C}_{9} \mathrm{H}_{13} \mathrm{~N}\) (g) A chiral quaternary ammonium salt, \(\mathrm{C}_{6} \mathrm{H}_{16} \mathrm{NCl}\)

Short answer

Question: Draw structural formulas for each of the following organic amines: (a) a 2° arylamine with molecular formula C7H9N, (b) a 3° arylamine with molecular formula C8H11N, (c) a 1° aliphatic amine with molecular formula C7H9N, (d) a chiral 1° amine with molecular formula C4H11N, (e) a 3° heterocyclic amine with molecular formula C6H11N, (f) a trisubstituted 1° arylamine with molecular formula C9H13N, and (g) a chiral quaternary ammonium salt with molecular formula C6H16NCl. Answer: (a) o-Toluidine:  (b) N,N-dimethylaniline:  (c) n-Heptyl amine:  (d) (S)-(+)-2-aminobutane: -(+)-2-Aminobutan.svg/1920px-(S)-(+)-2-Aminobutan.svg.png) (e) 1-Methylpyrrolidine:  (f) m-xylidine:  (g) (+)-Tris(1-methylethyl)amine hydrochloride: 

Step-by-step solution

(a) Draw a 2° arylamine with molecular formula C7H9N

For a 2° amine, two of the hydrogen atoms of the amine are replaced with alkyl or aryl groups. In this case, we are given a 2° arylamine. Arylamine has an aromatic ring attached to the nitrogen atom. The molecular formula C7H9N suggests there is one aromatic ring with 6 carbons, and an additional carbon is attached to the nitrogen. The structure for this compound is o-toluidine: 

(b) Draw a 3° arylamine with molecular formula C8H11N

A 3° arylamine has three alkyl or aryl groups connected to the nitrogen atom. In this case, we have a molecular formula of C8H11N, which suggests that there is one aromatic ring with 6 carbons, and one carbon attached to the nitrogen in each of the three bonds. The structure for this compound is N,N-dimethylaniline: 

(c) Draw a 1° aliphatic amine with molecular formula C7H9N

A 1° aliphatic amine has an aliphatic (non-aromatic) carbon chain with an NH2 group attached to it. In this case, the molecular formula is C7H9N. The structure we obtain is n-heptyl amine: 

(d) Draw a chiral 1° amine with molecular formula C4H11N

A chiral 1° amine has an asymmetric carbon atom with four unique substituent groups. The molecular formula is C4H11N. The chiral 1° amine for this formula is (S)-(+)-2-aminobutane: -(+)-2-Aminobutan.svg/1920px-(S)-(+)-2-Aminobutan.svg.png)

(e) Draw a 3° heterocyclic amine with molecular formula C6H11N

A 3° heterocyclic amine contains an N atom in a heterocyclic structure (nitrogen is part of a ring). The molecular formula is C6H11N. The resulting structure for this compound is 1-Methylpyrrolidine: 

(f) Draw a trisubstituted 1° arylamine with molecular formula C9H13N

A trisubstituted 1° arylamine has three substituent groups attached to the amine. The molecular formula C9H13N indicates the presence of one aromatic ring with 6 carbons, and 3 additional carbons attached to the nitrogen. The resulting structure is m-xylidine: 

(g) Draw a chiral quaternary ammonium salt with molecular formula C6H16NCl

A chiral quaternary ammonium salt has a central nitrogen atom attached to four non-hydrogen substituents and a counterion, like Cl-. In this case, we have molecular formula C6H16NCl. The structure for this compound is (+)-Tris(1-methylethyl)amine hydrochloride: