1. Chapter 12. Amines

2.  Organic derivatives of ammonia, NH 3,  Nitrogen atom with a lone pair of electrons, making amines both basic and nucleophilic  Occur in plants and animals

3.  Alkyl-substituted (alkylamines) or aryl-substituted (arylamines)  Classified: 1° (RNH 2 ), methyl (CH 3 NH 2 ), 2° (R 2 NH), 3° (R 3 N)  A nitrogen atom with four attached groups is positively charged....

4.  For simple amines, the suffix -amine is added to the name of the alkyl substituent.  Consider the  NH 2 as an amino substituent on the parent molecule.

5.  Symmetrical secondary and tertiary amines are named by adding the prefix di- or tri- to the alkyl group  Named as N-substituted primary amines  Largest alkyl group is the parent name, and other alkyl groups are considered N-substituents

6.  If the nitrogen atom occurs as part of a ring, the compound is designated as being heterocyclic  Each ring system has its own parent name

7.  Bonding to N is similar to that in ammonia ◦ N is sp 3 -hybridized ◦ C–N–C bond angles are close to 109° tetrahedral value  Amines with fewer than five carbons are water-soluble  Primary and secondary amines form hydrogen bonds, increasing their boiling points

8.  The lone pair of electrons on nitrogen makes amines basic and nucleophilic.

9.  Amines are stronger bases than alcohols, ethers, or water Larger pK b Smaller pK b

11.  The N lone-pair electrons in arylamines are delocalized by interaction with the aromatic ring  electron system and are less able to accept H + than are alkylamines  Amides (RCONH 2 ) in general are not proton acceptors.  Resonance form (resonance stabilization is lost upon protonation)

12. Purification of amines Acidic properties of primary and secondary amines

13.  Reduction of Nitriles and Amides

14.  Ammonia and other amines are good nucleophiles.  Unfortunately, these reactions don`t stop cleanly after a single alkylation.

15.  Azide ion, N 3  displaces a halide ion from a primary or secondary alkyl halide to give an alkyl azide, RN 3  Alkyl azides are not nucleophilic (but they are explosive)  Reduction gives the primary amine

16.  Treatment of an aldehyde or ketone with ammonia or an amine in the presence of a reducing agent

17.  Ammonia, primary amines, and secondary amines yield primary, secondary, and tertiary amines, respectively

18. Biological Pathway

19.  Reduction of nitro-compounds

20.  Alkylation and acylation have already been presented

21.  A heterocycle is a cyclic compound that contains atoms of two or more elements in its ring, usually C along with N, O, or S

22.  Pyrrole is an amine and a conjugated diene, however its chemical properties are not consistent with either of structural features  Aromatic compounds, 4n+2 rule..

23. Imidazole and Thiazole

24. Pyridine: Basic..

26. 12.7 Alkaloids: Naturally Occurring Amines Derived from Plant Source ‘Vegetable alkali’ (basic in aqueous solution) Less than 1% of all living species have been characterized