Basic Organic Nomenclature

An Introduction

Dave Woodcock,
Associate Professor Emeritus UBC (Okanagan)
©1996,2000, 2008

5. Functional Groups
with Suffix or Prefix

II Alkanamines
(Amines)

Index


Atomic grouping
Suffix-amine
Prefixamino
Position in chainanywhere
General formula CnH2n+3N

Note: since the suffix (-amine) has an initial vowel, the terminal -e of the alkane name is dropped before the suffix is added, even if a locant is placed immediately before the suffix.


One other point about amines: replacing the H atoms in the -NH2 group with other carbon groups does not significantly change the chemistry of the compounds (it is the strong C-N bond and the nitrogen lone pair of electrons which are mainly responsible for the chemistry). Consequently compounds with one, two or three carbon groups attached to nitrogen are all classified as amines. Historically, the designation primary, secondary, and tertiary amine has refered to the number of carbon atoms connected to the nitrogen. Take care to distinguish between a secondary amine (two carbons attached to nitrogen) and secondary alkanol (the OH group is attached to a carbon which itself is attached to two other carbons.
Finally, there are a number of acceptable ways of naming amines. The one given here is the one I prefer.

Examples : Primary Amines

StructureIUPAC NameModel
methanamine
ethanamine
propan-1-amine
propan-2-amine
ethane-1,2-diamine *
cyclopentanamine

* Because the suffix here is -diamine which starts with a consonant, the terminal -e of the alkane name is retained.


Examples : Secondary Amines

The longest chain of carbons takes the root name (alkanamine) and the other chain becomes a substituent with the locant N (italicised). The N is considered to be a lower locant than numerical locants, and so is placed ahead of them.
StructureIUPAC NameModel
N-methylmethanamine
N-methylethanamine
N-ethylethanamine
N-methylpentan-3-amine
N,3-dimethylbutan-2-amine


Examples : Tertiary Amines

The longest chain of carbons takes the root name (alkanamine) and the other chains become a substituents with the locant N (italicised). The N is considered to be a lower locant than numerical locants, and so is placed ahead of them.
StructureIUPAC NameModel
N,N-dimethylmethanamine
N,N-dimethylethanamine
N-ethyl-N-methylethanamine
N-ethyl-N-methylheptan-4-amine
Self Assignment Questions
Review Functional Groups with Prefix or Suffix I Introduction.

Next page : Alkanols.

Index


Main index page of MolecularModels.ca.

page upkeep by Dave: (email) who is solely responsible for the contents.

This document page last modified (mo/day/year) :