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7.8: Amines

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    The word "amine" is derived from ammonia, and the class of compounds known as amines therefore are commonly named as substituted ammonias. In this system, primary amines (\(RNH_2\)), having only one substituent on nitrogen, are named with the substituent as a prefix. More systematic nomenclature appends -amine to the longest chain, as for alcohols:

    From left to right: C H 3 N H 2; labeled methanamine (methylamine). Benzene ring with a N H 2 substituent; labeled benzenamine (phenylamine, aniline). C H 3 C H 2 C H 2 C (with C H 3 substituent) H N H 2; labeled 1-methylbutanamine (1-methylbutylamine). H 2 N (C H 2) 6 N H 2; labeled 1,6-hexanediamine.

    Secondary (\(R_2NH\)) and tertiary amines (\(R_3N\)), which have two and three substituents on nitrogen, commonly are named as N-substituted amines. As for substituted amides, N is included to indicate that the substituent is on the nitrogen atom unless there is no ambiguity as to where the substituent is located. Systematic nomenclature of secondary and tertiary amines is related to the systematic ether nomenclature discussed in Section 7-3:

    Top left: (C H 3) 2 N H; labeled N-methylmethanamine (dimethylamine). Top middle: cyclohexane with a N H C H 3 substituent; labeled N-methylcyclohexanamine (N-methylcyclohexylamine). Top right: (C L C H 2 C H 2) 2 N H; labeled 2-chloro-N-(2-chloroethyl) ethanamine [bis(2-chloroethyl)amine]. Bottom left: cyclohexane with a N (C H 3) 2 substituent; labeled N,N-dimethylcyclohexanamine (N,N-dimethylcyclohexylamine). Bottom right: benzene ring with a N C H 2 C H 3 substituent. C H 3 attached to the nitrogen. Labeled N-ethyl-N-methylbenzeneamine (N-ethyl-N-methylaniline).

    As a substituent, the \(-NH_2\) group is called amino. N-Substituted amino groups are named accordingly:

    Left: C H 3 N H dash; labeled N-methylamino. Right: (C 6 H 5) 2 N dash; N,N-diphenylamino.

    \(^1\)Alphabetical order puts chloro- ahead of chloroethyl-.

    Contributors and Attributions

    John D. Robert and Marjorie C. Caserio (1977) Basic Principles of Organic Chemistry, second edition. W. A. Benjamin, Inc. , Menlo Park, CA. ISBN 0-8053-8329-8. This content is copyrighted under the following conditions, "You are granted permission for individual, educational, research and non-commercial reproduction, distribution, display and performance of this work in any format."

    This page titled 7.8: Amines is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by John D. Roberts and Marjorie C. Caserio.