CHEM 30 B    Dr. R. Rinehart         
Chapter 16: AMINES and AMIDES

             Along with Chapter 15, this chapter will help to prepare us for our look at amino acids and proteins in Chapter 19. So this stuff is important!  

I. AMINES: can be thought of as substituted ammonia molecules
           
A. Classification: by # of H in NH3 replaced by R; NOTE differences from alcohol classes
                       
1.
Primary 1o : RNH2
                       
2.
Secondary 2o : RNHR’  or R2NH
                       
3.
Tertiary 3o : RNR’R”  or R3N 
            B. NOMENCLATURE
                       
1.
Common: Name the groups attached to N [in alphabetical order] followed by amine
                        2. IUPAC

   
                             a.  Use the prefix -amino with a number locant; to determine the longest
                        
            relevant chain; the
priority of  the -NH2 group is less than -OH but greater
                        
            than  C=O
                        
         b.
If the amino group is the highest priority group in the compound, locate
   
                                  the longest chain  containing it and
add the suffix –amine to the parent
   
                                  hydrocarbon name [minus the e at the end];  for secondary and tertiary
   
                                  amines, 
identify the other groups attached to nitrogen by name and prefix
   
                                  with N- to show that they are attached to the N 
                       
3. Aromatic amines: usually named as derivatives of aniline, C6H5NH2

            C. Physical properties 
                       
1. b.p. higher than alkanes, less than alcohols of  ~ m.w.
                       
2. <C6 soluble in H2O
                       
3. sharp, unpleasant, “fishy” odors
[check out “putrescine” and “cadaverine”]

            D. Chemical properties and reactions
                       
1.
Basicity: RNH2 + H2O à RNH3+ + OH-; Form salts with acids
                       
2.
Ammonium ions: 1o RNH3+,  2o R2NH2+,  3o R3NH+ ,  4o  R4N+
                       
3. React with carboxylic acids to form
amides [an intermolecular dehydration]

            E . Biologically important amines and “alkaloids”
                       
1. Hormones and neurotransmitters: (nor)epinephrine,dopamine, serotonin,
                        
            histamine, etc.
                       
2. Alkaloids: nitrogen-containing compounds from plants; many with 
                        
            pharmacological activity: opiates, cocaine, mescaline, caffeine, etc.
 

Click on links below to see my: 
table of amines and N-containing heterocycles
table of amino acids
table of neurotransmitters, hormones, and alkaloids
To see Dave Woodcock's Chime structures of amines [new window] go to:
http://www.molecularmodels.ca/molecule/Amines.htm

PowerPoint-type presentation of nitrogen-containing functional groups [amines, amides, etc.] by Warren Gallagher at U Wisconsin Eau Claire is viewable [with Acrobat Reader] at:
http://web.archive.org/web/20060504011433/http://www.chem.uwec.edu/Chem150_S06/Pages/lecture-materials.html
> Lecture 4
 http://www.chem.uwec.edu/Chem150_S06/Pages/lecture-materials.html  > Lecture 4
Or, check http://www.chem.uwec.edu/Chem150_S07/content.html > Unit 7

Amines by Gary Trammell at the University of Illinois, Springfield
http://people.uis.edu/gtram1/organic/aminesmenu.htm

II. AMIDES: RCONH2, RCONHR’, RCONR2
           
A. FORMATION from carboxylic acid [or anhydride] + NH3, RNH2, or R2NH [NOT R3N]
           
B. NOMENCLATURE: based on the acid involved; e.g., N-methyl acetamide
           
C. Physical properties: most are solids @ room temperature; <C6 water-soluble
           
D. CHEMICAL properties:
                       
1. Neutral
                       
2. Hydrolyzed by acid or base, but more stable than esters
                       
3. The amide [“peptide”] bond is the basis of protein formation by the
                        
            polymerization of
a-amino acids
           
E. Biologically and economically important amides 
                       
1. PROTEINS
                       
2. drugs: acetaminophen, salicylamide, barbiturates, benzodiazepines [valium, etc.],
   
                              penicillins,etc.
                       
3. polymers: nylon, Kevlar, Nomex, etc. 

Click on link below to see my: 
table of amides and polyamides
To see Dave Woodcock's Chime structures of amides [new window] go to:
http://www.molecularmodels.ca/molecule/Amides.htm

 

© Ronald W. Rinehart, 2002-2007    Close this window to return to class schedule or click here