What are carboxylic acids, esters, amines, and amides?

1. What are carboxylic acids, esters, amines, and amides? A carboxylic acid contains a carboxyl group, which • is a carbonyl group (C=O) attached to a hydroxyl group (—OH). • is found on carbon 1 in carboxylic acids. O  CH3 —C—OHhydroxyl groupor CH3COOH carbonyl group

2. How to name carboxylic acids? IUPAC names • Replace the -e in the alkane name with -oic acid. CH4 methane HCOOH methanoicacid CH3—CH3 ethane CH3—COOH ethanoicacid • Number substituents from the carboxyl carbon 1. CH3 O | ║ CH3—CH—CH2—C—OH 4 3 2 1 3-methylbutanoic acid three-dimensional models

3. Some common carboxylic acids Methanoic acid (formic acid) O ║ H─C─OH ethanoic acid (acetic acid) O ║ CH3─C─OH

4. Aromatic carboxylic acids Benzoic acid • aromatic carboxylic acid. • locates substituents by numbering the ring from carbon 1 in the carboxyl group. benzoic acid 3-chlorobenzoic acid 4-aminobenzoic acid

5. Polarity of carboxylic acids Carboxylic acids • are strongly polar. • have two polar groups: hydroxyl (−OH) and carbonyl (C=O).

6. Solubility in water Carboxylic acids: • form hydrogen bonds with many water molecules. • with 1-4 carbon atoms are very soluble in water. • as carbon atoms increase in chains, solubility decreases. Water molecules

7. Acidity of carboxylic acids Carboxylic acids • are weak acids. • ionize in water to produce carboxylate ions and hydronium ions.

8. Neutralization of carboxylic acids Carboxylic acid salts • product of neutralization of a carboxylic acid • with a strong base. CH3—COOH + NaOH CH3—COO– Na+ + H2O acetic acid sodium acetate (carboxylic acid salt) • are used as preservatives and flavor enhancers.

9. What are esters? Esters give flowers and fruits their pleasant fragrances and flavors. In an ester, the H in the carboxyl group is replaced with an alkyl group. not learning how to name them! O  CH3 —C—O —CH3 ester group

10. What is esterification? Esterification is the reaction of a carboxylic acid and alcohol in the presence of an acid catalyst to produce an ester. O  H+ CH3—C—OH+H—O—CH2—CH3 O  CH3—C—O—CH2—CH3 +H2O ethyl acetate (an ester)

11. Ester products Aspirin • is used to relieve pain and reduce inflammation. • is an ester of salicylic acid and acetic acid. Oil of wintergreen • is used to soothe sore muscles. • is an ester of salicylic acid and methanol.

12. Base Hydrolysis (Saponification) Base hydrolysis or saponification, • is the reaction of an ester with a strong base. • produces the salt of the carboxylic acid and an alcohol • Salt- “soap” O || CH3—C—O—CH2—CH3 +NaOH O CH3—C—O–Na+ + HO—CH2—CH3 salt of carboxylic acid alcohol

13. Cleaning action of soap A soap • contains a nonpolar end that dissolves in nonpolar fats and oils, and a polar end that dissolves in water. • forms groups of soap molecules called micelles that dissolve in water and are washed away.

14. N H 2 Amines Amines • are derivatives of ammonia, NH3. • contain N attached to one or more alkyl or aromatic groups. CH3 CH3   CH3—NH2 CH3—NH CH3—N—CH3

15. Amines are classified as primary, secondary, or tertiary. • primary (1°) amine, one carbon group is bonded to nitrogen atom. • secondary(2°) amine has two carbon groups bonded to nitrogen atom. • tertiary(3°) amine has three carbon groups bonded to nitrogen atom. H CH3 CH3 ||| CH3—N—HCH3—N—H CH3—N—CH3 1° 2° 3°

16. Naming Amines Simple amines • are named as alkylamines. • List the names of the alkyl groups bonded to the N atom in alphabetical order in front of amine. CH3—CH2—NH2 ethylamine CH3—NH—CH3dimethylamine CH3 | CH3—N—CH2—CH3ethyldimethylamine

17. Aromatic Amines • The amine of benzene is named aniline. • Alkyl groups on the N use the prefix N- with alkyl name. aniline 3-chloroaniline N-methylaniline

18. Hydrogen bonding for amines The N−H bond • provides hydrogen bonding in 1°and 2° amines, but not in 3° amines. • is not as polar as the O-H bonds in alcohols.

19. Solubility in water Amines • with 1-5 carbon atoms are soluble in water. • form hydrogen bonds with the polar O-H bond in water.

20. Amines react as bases Like ammonia, amines are weak bases in water. NH3 + H2O NH4+ + OH– ammonium hydroxide CH3—NH2 + H2O CH3—NH3+ + OH– methylammonium hydroxide • forms when an amine is neutralized by acid.

21. Properties of amine salts Amine salts are • solids at room temperature. • soluble in water and body fluids. • the form used for drugs.

22. Alkaloids Alkaloids are • physiologically active nitrogen-containing compounds. • obtained from plants. • used as anesthetics, antidepressants, and in stimulants such as caffeine. • often addictive.

23. Cocaine Cocaine is • sold illegally as the amine salt. • reacted with NaOH to produce the free amine form known as “crack.”

24. Caffeine Caffeine • is a stimulant of the central nervous system. • is found in coffee beans, tea, chocolate, and soft drinks.

25. N C H 3 Nicotine Nicotine • increases the adrenaline level in the blood. • causes addiction to tobacco.

26. Morphine and Codeine Morphine and codeine are • alkaloids. • obtained from the oriental poppy plant. • used as painkillers. • modified to make heroin.

27. Amides In amides, • an amino group(–NH2) replaces the –OH group of carboxylic acids. • The aromatic amine is benzamide. O O |||| CH3—C—OHCH3—C—NH2 benzamide

28. Some amides in health and medicine • Urea is the end product of protein metabolism. • Saccharin is an artificial sweetener. • Some amides such as phenobarbital, Nembutal and Seconal are barbiturates. • Acetaminophen is used to reduce fever and pain.

29. Physical properties of amides Amides • that are primary (−NH2) or secondary (−NH−)form hydrogen bonds. • that are primary have higher melting points than secondary. • that are tertiary (no H on N) do not form hydrogen bonds and have lower melting points. • all form hydrogen bonds with water. • with 1-5 carbon atoms are soluble in water.

30. Hydrogen bonding of amides O || CH3—C—N—H | H Hydrogen bonding occurs between primary amides. O || CH3—C—N—H | H