{"id":1652,"date":"2018-03-21T15:37:11","date_gmt":"2018-03-21T15:37:11","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/suny-orgbiochemistry\/chapter\/amines-structures-and-names\/"},"modified":"2018-11-08T20:09:30","modified_gmt":"2018-11-08T20:09:30","slug":"amines-structures-and-names","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-monroecc-orgbiochemistry\/chapter\/amines-structures-and-names\/","title":{"raw":"15.11 Amines: Structures and Names","rendered":"15.11 Amines: Structures and Names"},"content":{"raw":"
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Learning Objectives<\/h3>\r\n
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  1. Identify the general structure for an amine.<\/li>\r\n \t
  2. Identify the functional group for amines.<\/li>\r\n \t
  3. Determine the structural feature that classifies amines as primary, secondary, or tertiary.<\/li>\r\n \t
  4. Use nomenclature systems to name amines.<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n

    Amines are classified according to the number of carbon atoms bonded directly to the nitrogen atom. A primary (1\u00b0) amine<\/span>A compound that has only one alkyl or aryl group on the nitrogen atom.<\/span><\/span> has one alkyl (or aryl) group on the nitrogen atom, a <\/span>secondary (2\u00b0) amine<\/span>A compound that has two alkyl or aryl groups on the nitrogen atom.<\/span><\/span> has two, and a <\/span>tertiary (3\u00b0) amine<\/span>A compound that has three alkyl or aryl groups on the nitrogen atom.<\/span><\/span> has three (<\/span>Figure 15.5 \"The Structure of Amines Compared to Water, an Alcohol, and an Ether\"<\/a>).<\/span><\/p>\r\n\r\n

    \r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"1500\"]\"image\" Figure 15.5 The Structure of Amines Compared to Water, an Alcohol, and an Ether.[\/caption]\r\n\r\n<\/div>\r\n
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    \"image\"<\/div>\r\n<\/div>\r\n

    The common names for simple aliphatic amines consist of an alphabetic list of alkyl groups attached to the nitrogen atom, followed by the suffix -amine<\/em>. (Systematic names are often used by some chemists.) The amino group<\/span><\/span> -NH2<\/sub> is named as a substituent in more complicated amines such as those that incorporate other functional groups or in which the alkyl groups cannot be simply named.<\/p>\r\n\r\n

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    Example 9<\/h3>\r\n

    Name each compound and classify as 1o<\/sup>, 2o<\/sup>, or 3o<\/sup>.<\/p>\r\n\r\n

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    1. CH3<\/sub>CH2<\/sub>CH2<\/sub>NH2<\/sub><\/li>\r\n \t
    2. \r\n
      \"image\"<\/div><\/li>\r\n \t
    3. CH3<\/sub>CH2<\/sub>NHCH2<\/sub>CH3<\/sub><\/li>\r\n \t
    4. CH3<\/sub>CH2<\/sub>CH2<\/sub>NHCH3<\/sub><\/li>\r\n<\/ol>\r\n[reveal-answer q=\"675468\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"675468\"]\r\n
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      1. There is only one alkyl group attached to the nitrogen atom, so the amine is primary. A group of three carbon atoms (a propyl group) is attached to the NH2<\/sub> group through an end carbon atom, so the name is propylamine.<\/li>\r\n \t
      2. There are two methyl groups and one ethyl group on the nitrogen atom. The compound is ethyldimethylamine, a tertiary amine.<\/li>\r\n \t
      3. There are two ethyl groups attached to the nitrogen atom; the amine is secondary, so the compound is diethylamine.<\/li>\r\n \t
      4. The nitrogen atom has a methyl group and a propyl group, so the compound is methylpropylamine, a secondary amine.[\/hidden-answer]<\/li>\r\n<\/ol>\r\n<\/div>\r\n
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        Skill-Building Exercise<\/h3>\r\n

        Name and classify each compound.<\/p>\r\n\r\n

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        1. \r\n
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          \"image\"<\/div>\r\n<\/div><\/li>\r\n \t
        2. \r\n
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          \"image\"<\/div>\r\n<\/div><\/li>\r\n \t
        3. \r\n
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          CH3<\/sub>CH2<\/sub>CH2<\/sub>CH2<\/sub>NH2<\/sub><\/p>\r\n\r\n<\/div><\/li>\r\n \t

        4. \r\n
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          CH3<\/sub>CH2<\/sub>CH2<\/sub>NHCH2<\/sub>CH2<\/sub> CH3<\/sub><\/p>\r\n\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n

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          Example 10<\/h3>\r\n

          Draw the structure for each compound and classify as primary, secondary, or tertiary.<\/p>\r\n\r\n

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          1. isopropyldimethylamine<\/li>\r\n \t
          2. dipropylamine<\/li>\r\n<\/ol>\r\n

            [reveal-answer q=\"246990\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"246990\"]<\/p>\r\n

            1. The name indicates that there are an isopropyl group (in red) and two methyl groups (in green) attached to the nitrogen atom; the amine is tertiary.<\/p>\r\n\r\n

            \"image\"<\/div>\r\n

            2. The name indicates that there are two propyl groups attached to the nitrogen atom; the amine is secondary. (The third bond on the nitrogen atom goes to a hydrogen atom.)<\/p>\r\n

            CH3<\/sub>CH2<\/sub>CH2<\/sub>NHCH2<\/sub>CH2<\/sub>CH3\u00a0<\/sub>[\/hidden-answer]<\/span><\/span><\/p>\r\n\r\n<\/div>\r\n

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            Skill-Building Exercise<\/h3>\r\n

            Draw the structure for each compound and classify.<\/p>\r\n\r\n

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            1. \r\n
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              ethylisopropylamine<\/p>\r\n\r\n<\/div><\/li>\r\n \t

            2. \r\n
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              diethylpropylamine<\/p>\r\n\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n

              The primary amine in which the nitrogen atom is attached directly to a benzene ring has a special name\u2014aniline. Aryl amines are named as derivatives of aniline.<\/p>\r\n\r\n

              \"image\"<\/div>\r\n
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              Example 11<\/h3>\r\n

              Name this compound.<\/p>\r\n\r\n

              \"image\"[reveal-answer q=\"364837\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"364837\"]The benzene ring with an amino (NH2<\/sub>) group is aniline. The compound is named as a derivative of aniline: 3-bromoaniline or m-bromoaniline.[\/hidden-answer]<\/div>\r\n<\/div>\r\n
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              Skill-Building Exercise<\/h3>\r\n
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              1. \r\n
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                Name this compound.<\/p>\r\n\r\n

                \"image\"<\/div>\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
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                Example 12<\/h3>\r\n

                Draw the structure for 4-ethylaniline and classify.<\/p>\r\n

                [reveal-answer q=\"16012\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"16012\"]The compound is a derivative of aniline. It is a primary amine having an ethyl group located at carbon 4 when amino (-NH2<\/sub>) group is attached to carbon 1.<\/p>\r\n\r\n

                \"image\"[\/hidden-answer]<\/div>\r\n<\/div>\r\n
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                Skill-Building Exercise<\/h3>\r\n
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                1. \r\n
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                  Draw the structure for 4-isopropylaniline and classify.<\/p>\r\n\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n

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                  Example 13<\/h3>\r\n

                  Draw the structure for 2-amino-3-methylpentane.<\/p>\r\n

                  [reveal-answer q=\"546930\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"546930\"]Always start with the parent compound: draw the pentane chain. Then attach a methyl group at the third carbon atom and an amino group at the second carbon atom.\"image\"<\/p>\r\n

                  [\/hidden-answer]<\/p>\r\n\r\n<\/div>\r\n

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                  Skill-Building Exercise<\/h3>\r\n
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                  1. \r\n
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                    Draw the structure for 2-amino-3-ethyl-1-chloroheptane.<\/p>\r\n\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n

                    Ammonium (NH4<\/sub>+<\/sup>) ions, in which one or more hydrogen atoms are replaced with alkyl groups, are named in a manner analogous to that used for simple amines. The alkyl groups are named as substituents, and the parent species is regarded as the NH4<\/sub>+<\/sup> ion. For example, CH3<\/sub>NH3<\/sub>+<\/sup> is the methylammonium ion. The ion formed from aniline (C6<\/sub>H5<\/sub>NH3<\/sub>+<\/sup>) is called the anilinium ion.<\/p>\r\n\r\n

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                    Example 14<\/h3>\r\n

                    Name each ion.<\/p>\r\n\r\n

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                    1. CH3<\/sub>NH3<\/sub>+<\/sup><\/li>\r\n \t
                    2. (CH3<\/sub>)2<\/sub>NH2<\/sub>+<\/sup><\/li>\r\n \t
                    3. (CH3<\/sub>)3<\/sub>NH+<\/sup><\/li>\r\n \t
                    4. (CH3<\/sub>)4<\/sub>N+<\/sup> (note that this is a quaternary or 4o<\/sup> amine)<\/li>\r\n<\/ol>\r\n

                      [reveal-answer q=\"78377\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"78377\"]<\/p>\r\n

                      The ions have one, two, three, and four methyl (CH3) groups attached to a nitrogen atom. Their names are as follows:<\/p>\r\n\r\n

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                      1. methylammonium ion<\/li>\r\n \t
                      2. dimethylammonium ion<\/li>\r\n \t
                      3. trimethylammonium ion<\/li>\r\n \t
                      4. tetramethylammonium ion[\/hidden-answer]<\/li>\r\n<\/ol>\r\n<\/div>\r\n
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                        Skill-Building Exercise<\/h3>\r\nName each ion.\r\n
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                        1. \r\n
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                          CH3<\/sub>CH2<\/sub>NH3<\/sub>+<\/sup><\/p>\r\n\r\n<\/div><\/li>\r\n \t

                        2. \r\n
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                          (CH3<\/sub>CH2<\/sub>)3<\/sub>NH+<\/sup><\/p>\r\n\r\n<\/div><\/li>\r\n \t

                        3. \r\n
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                          (CH3<\/sub>CH2<\/sub>CH2<\/sub>)2<\/sub>NH2<\/sub>+<\/sup><\/p>\r\n\r\n<\/div><\/li>\r\n \t

                        4. \r\n
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                          (CH3<\/sub>CH2<\/sub>CH2<\/sub>CH2<\/sub>)4<\/sub>N+<\/sup><\/p>\r\n\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n

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                          Concept Review Exercises<\/h3>\r\n
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                          1. \r\n
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                            To what inorganic compound are the amines related?<\/p>\r\n\r\n<\/div><\/li>\r\n \t

                          2. \r\n
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                            How are amines classified?<\/p>\r\n\r\n<\/div><\/li>\r\n<\/ol>\r\n<\/div>\r\n

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                            [reveal-answer q=\"85306\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"85306\"]<\/p>\r\n\r\n

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                            1. ammonia<\/li>\r\n \t
                            2. by the number of hydrocarbon groups on the nitrogen atom: primary amine, one group; secondary amine, two groups; tertiary amine, three groups; quaternary amine, four groups.\u00a0 [\/hidden-answer]<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
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                              Key Takeaways<\/h3>\r\n<\/div>\r\n
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