Chemistry · Ch 13 — Organic Nitrogen Compounds
Nomenclature of Amines
Nomenclature of Amines
Amines are named two ways. In the COMMON system, an aliphatic amine is named by prefixing the alkyl group to 'amine' (isopropylamine, benzylamine), with di-/tri-/tetra- prefixes for two, three or four identical substituents. In the IUPAC system, the amine is named as an '-amine' suffix on the parent chain, with the position given a locant where needed (propan-2-amine for isopropylamine; prop-2-en-1-amine for allylamine) and any additional N-substituents cited as N-alkyl/N-aryl prefixes (N-methylpropan-2-amine for methylisopropylamine; N,N-diethylbutan-1-amine for diethylbutylamine; N-ethyl-N-methylpropan-2-amine for ethylmethylisopropylamine). A symmetric diamine is named with locants for both -NH2 groups, e.g. hexane-1,6-diamine for hexamethylenediamine. Aromatic amines follow the same suffix logic on 'benzenamine' (N,N-dimethylbenzenamine for N,N-dimethyl …
| Compound (common name) | Structural formula | IUPAC name |
|---|---|---|
| Isopropylamine | (CH3)2CH-NH2 | Propan-2-amine |
| Allylamine | CH2=CH-CH2-NH2 | Prop-2-en-1-amine |
| Hexamethylene diamine | H2N-(CH2)6-NH2 | Hexane-1,6-diamine |
| Methyl isopropyl amine | CH3-NH-CH(CH3)2 | N-Methylpropan-2-amine |
| Diethyl butylamine | (C2H5)2N-CH2CH2CH2CH3 | N,N-Diethylbutan-1-amine |
| Ethyl methyl isopropylamine | CH3(C2H5)N-CH(CH3)2 | N-Ethyl-N-methylpropan-2-amine |
| N,N-Dimethyl aniline | C6H5-N(CH3)2 | N,N-Dimethylbenzenamine |
Worked out. Book's practice box (no printed solution): draw the structures of (i) neopentylamine, (ii) tert-butylamine, (iii) alpha-aminopropionaldehyde, (iv) tribenzylamine, (v) N-ethyl-N-methylhexan-3-amine. Working through them: (i) neopentylamine is (CH3)3C-CH2-NH2 (a primary amine on the CH2 next to a quaternary carbon); (ii) tert-butylamine is (CH3)3C-NH2; (iii) alpha-aminopropionaldehyde is CH3-CH(NH2)-CHO (an amino group on the carbon alpha to the aldehyde); (iv) tribenzylamine is (C6H5CH2)3N (a tertiary amine with three identical benzyl groups); (v) N-ethyl-N-methylhexan-3-amine is CH3-CH2-CH(N(CH3)(C2H5))-CH2-CH2-CH3 (a tertiary amine on C3 of a hexane chain, bearing an N-ethyl and an N-methy …
Worked out. Book's practice box (no printed solution): give the correct IUPAC names for (i) CH3-CH2-CH2-CH(NH2)-CH3, (ii) CH3-CH2-CH(NHCH3)-CH3, (iii) a drawn aniline-type ring (a primary aromatic amine), (iv) a drawn hydroxyl + amino substituted ring, and (v) a drawn cyclic/heteroaromatic amine. Working through them: (i) pentan-2-amine (the 5-carbon chain numbered to give -NH2 the lower locant, 2); (ii) N-methylbutan-2-amine (a secondary amine, -NHCH3 on C2 of a butane chain); (iii) benzenamine (aniline, the simplest aromatic primary amine); (iv) 4-aminophenol (or 2-aminophenol, depending on the relative ring positions of -OH and -NH2 as drawn); (v) pyridin-... -amine or a similarly numbered heterocyclic amine name, depending on the exact ring …